Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Note 1 – Summary of Significant Accounting Policies Basis of Presentation The unaudited condensed consolidated financial statements of T-Mobile US, Inc. (“T-Mobile,” “we,” “our,” “us” or the “Company”) include all adjustments of a normal recurring nature necessary for the fair presentation of the results for the interim periods presented. The results for the interim periods are not necessarily indicative of those for the full year. The condensed consolidated financial statements should be read in conjunction with our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019. On April 29, 2018, we entered into a Business Combination Agreement (the “Business Combination Agreement”) to merge with Sprint Corporation (“Sprint”) in an all-stock transaction at a fixed exchange ratio of 0.10256 shares of T-Mobile common stock for each share of Sprint common stock, or 9.75 shares of Sprint common stock for each share of T-Mobile common stock (the “Merger”). On April 1, 2020, we completed the Merger and acquired Sprint (see Note 2 - Business Combination). On July 26, 2019, pursuant to the requirement as set forth in the U.S. Department of Justice’s (the “DOJ”) complaint and proposed final judgement (the “Consent Decree), T-Mobile entered into an Asset Purchase Agreement (the “Asset Purchase Agreement”) with Sprint and DISH Network Corporation (“DISH”). Pursuant to the Asset Purchase Agreement and upon the terms and subject to the conditions thereof, on July 1, 2020 DISH acquired the prepaid wireless business operated under the Boost Mobile and Sprint prepaid brands (excluding the Assurance brand Lifeline customers and the prepaid wireless customers of Shenandoah Telecommunications Company and Swiftel Communications, Inc.), including customer accounts, inventory, contracts, intellectual property and certain other specified assets (the “Prepaid Business”) and assumed certain related liabilities (the “Prepaid Transaction”). Upon closing of the Prepaid Transaction, we received $1.4 billion from DISH, subject to a working capital adjustment. The assets and liabilities of the Prepaid Business are presented as held for sale as of June 30, 2020 and revenues and expenses are presented as discontinued operations for the three and six months ended June 30, 2020. The condensed consolidated financial statements include the balances and results of operations of T-Mobile and our consolidated subsidiaries. We consolidate majority-owned subsidiaries over which we exercise control, as well as variable interest entities (“VIEs”) where we are deemed to be the primary beneficiary and VIEs which cannot be deconsolidated, such as those related to our obligations to pay for the management and operation of certain of our wireless communications tower sites. Intercompany transactions and balances have been eliminated in consolidation. The preparation of financial statements in conformity with United States (“U.S.”) generally accepted accounting principles (“GAAP”) requires our management to make estimates and assumptions which affect the financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and other assumptions which our management believes are reasonable under the circumstances, including but not limited to the valuation of assets acquired and liabilities assumed through the Merger with Sprint and the potential impacts arising from the COVID-19 pandemic. These estimates are inherently subject to judgment and actual results could differ from those estimates. Significant Accounting Policies Upon the close of our Merger with Sprint, we have adopted or applied the significant accounting policies below to the applicable transactions and activities of the consolidated company. Spectrum Leases Through the Merger, the Company acquired lease agreements (the “Agreements”) with various educational and non-profit institutions that provide us with the right to use Federal Communications Commission (“FCC”) spectrum licenses (Educational Broadband Services or “EBS spectrum”) in the 2.5 GHz band. In addition to the Agreements with educational institutions and private owners who hold the license, the Company also acquired direct ownership of spectrum licenses previously acquired by Sprint through government auctions or other acquisitions. The Agreements with educational and certain non-profit institutions are typically for five to ten years with automatic renewal provisions, bringing the total term of the agreement up to 30 years. Majority of the Agreements include a right of first refusal to acquire, lease or otherwise use the license at the end of the two automatic renewal periods. Leased FCC spectrum licenses are recorded as executory contracts whereby, as a result of business combination accounting, an intangible asset or liability is recorded reflecting the extent to which contractual terms are favorable or unfavorable to current market rates. These intangible assets or liabilities are amortized over the estimated remaining useful life of the lease agreements. Contractual lease payments are recognized on a straight-line basis over the remaining term of the arrangement, including renewals, and are presented in Costs of services within our Condensed Consolidated Statements of Comprehensive Income. Owned FCC spectrum licenses are classified as indefinite-lived intangible assets which are assessed for impairment annually, or more frequently, if facts and circumstances warrant. The Agreements enhance the value of the Company’s owned spectrum licenses as the collective value is higher than the value of individual bands of spectrum within a specific geography. This value is derived from the ability to provide wireless service to customers across large geographic areas and maintain the same or similar wireless connectivity quality. This enhanced value from combining owned and leased spectrum licenses to create contiguous spectrum is referred to as an aggregation premium. We recognized the aggregation premium as part of the FCC spectrum licenses indefinite-lived intangible assets which are assessed for impairment annually or more frequently if facts and circumstances warrant. Brightstar Distribution We have arrangements with Brightstar US, Inc. (“Brightstar”), a subsidiary of Softbank, whereby Brightstar provides supply chain and inventory management services to us in our indirect channels. T-Mobile may sell devices through Brightstar to T-Mobile indirect dealers. The supply chain and inventory management arrangement includes, among other things, that Brightstar may purchase inventory from the original equipment manufacturers (“OEM”) to sell directly to our indirect dealers. As compensation for these services, we remit per unit fees to Brightstar for each device sold to these indirect dealers. Devices sold from T-Mobile to Brightstar do not meet the criteria for a sale, as control is not transferred until devices are sold through to indirect dealers, and in some cases, end customers. Devices transferred from T-Mobile to Brightstar remain in inventory until control is transferred to the indirect dealers or end customers. For service subscribers who choose to lease a device previously sold to the dealer, T-Mobile will repurchase the device from the dealer and originate a lease directly with the service subscriber. Repurchase activity from the dealer is estimated and treated as a right of return, reducing equipment revenue at the time of sale to the dealer. Upon lease to the end customer, T-Mobile recognizes lease revenue over the associated lease term within Equipment revenues in our Condensed Consolidated Statements of Comprehensive Income. Device Leases Through the Merger, we acquired device lease contracts in which Sprint is the lessor, substantially all of which are classified as operating leases, and the associated fixed assets. These leased devices were recorded as fixed assets at their acquisition date fair value and presented within Property and equipment, net on our Condensed Consolidated Balance Sheets. These devices are depreciated using the group method over the estimated remaining useful life to their estimated residual value. The estimated useful life reflects the period for which we estimate the group of leased devices will provide utility to us, which may be longer than the initial lease term based on customer options in the Sprint Flex Lease program to renew the lease on a month-to-month basis after the initial lease term concludes. Revenues associated with the leased wireless devices, net of lease incentives, are generally recognized straight-line over the lease term. T-Mobile depreciates leased devices on a group basis using the straight-line method over the estimated useful life of the device, which considers the lease term (e.g., 18 months and month-to-month renewal options for the Sprint Flex Lease program), trade-in activity and write-offs for lost and stolen devices. Lost and stolen devices are incorporated into the estimates of depreciation expense and recognized as an adjustment to accumulated depreciation when the loss event occurs. The Company’s policy using the group method of depreciation has been applied to acquired leased devices as well as leases originated subsequent to the Merger close. Acquired leased devices are grouped based on the age of the device. Upon device upgrade or at lease end, customers in the Jump on Demand lease program must return or purchase their device. Customers in the Sprint Flex Lease program have the option to return or purchase their device or to renew their lease on a month-to-month basis at the end of the lease term. Returned devices are transferred from Property and equipment, net to Inventory on our Condensed Consolidated Balance Sheets and are valued at the lower of cost or net realizable value, with any write-down recognized as Cost of equipment sales in our Condensed Consolidated Statements of Comprehensive Income. Cost to Acquire a Contract T-Mobile capitalizes postpaid sales commissions for service activation as costs to acquire a contract and amortizes them over 24 months. Prepaid commissions are expensed as incurred as their estimated period of benefit does not extend beyond 12 months. Commissions paid upon device upgrade are not capitalized if a customer contract is less than one year. Commissions paid when the customer has a lease are treated as initial direct costs and recognized over the lease term. T-Mobile policies for the capitalization and amortization of costs to acquire a contract are applied to the Sprint, Boost and Assurance Wireless brands subsequent to Merger close. Device Purchases Cash Flow Presentation T-Mobile classifies all device purchases as operating cash outflows as T-Mobile’s predominant strategy is to sell devices to customers rather than lease them. Devices acquired for sale or lease to Sprint, Boost and Assurance Wireless customers are similarly classified as operating cash outflows. Imputed Interest on EIP Receivables T-Mobile records the effects of financing on all equipment installment plan (“EIP”) loans regardless as to whether the financing is considered to be significant or not. The imputation of interest results in a discount of the EIP receivable thereby adjusting the transaction price of the contract with the customer, which is then allocated to the performance obligations of the arrangement. For indirect channel loans to the end service customer in which the sale of the device was to the dealer (sell-in basis), the effect of imputing interest is recognized as a reduction to service revenue, the only performance obligation with the service customer as the device sale was recognized when transferred to the dealer, and over the service contract period. T-Mobile policies for imputed interest on EIP receivables are applied to loans originated for Sprint and Boost customers subsequent to Merger close. Cell Tower Lease-Out and Leaseback Arrangement Prior to the Merger, Sprint entered into a lease-out and leaseback agreement with a tower operator (Global Signal, Inc. a third party that was subsequently acquired by Crown Castle International Corp. (“CCI”)). The tower operator was granted exclusive rights to lease 6,600 communications towers (lease-out) for 32 years, which were originally constructed by Sprint on land that Sprint leased from individual landowners. Sprint received upfront proceeds in 2005 of $1.2 billion and obtained the right to use a portion of the space on the towers with a stipulated monthly payment (leaseback), generally with a 10-year initial term with five-year renewal options. The arrangement is accounted for as a financing with the cell towers owned by Sprint included in Property and equipment and a financing obligation for the amounts contractually due to CCI included in Tower obligations in our Condensed Consolidated Balance Sheets. The tower assets are depreciated to their estimated residual value and payments to CCI are recognized as interest expense and a reduction to the financing obligation. See Note 9 – Tower Obligati ons for further information on this arrangement. Wireline revenue Performance obligations related to our Wireline customers involve the provision of services to corporate customers. Wireline service performance obligations are typically satisfied over a period between 24 and 36 months. Amounts due for services are invoiced and collected periodically over the relevant service period. Wireline contracts are not subject to significant amounts of variable consideration, other than charges intended to partially recover taxes imposed on the Company, including fees related to the Universal Service Fund. Such fees are based on the customer's monthly usage and are therefore included in the corresponding distinct months of Wireline services. Our Wireline contracts do provide the customer with monthly options to purchase goods or services at prices commensurate with the standalone selling prices for those goods or services, as determined at contract inception. Wireline revenues are included within Roaming and other service revenues in our Condensed Consolidated Statements of Comprehensive Income. Sprint Retirement Pension Plan Through the Merger, we acquired the assets and assumed the liabilities associated with the Sprint Retirement Pension Plan (the “Pension Plan”), which is a defined benefit pension plan providing postretirement benefits to certain employees. As of December 31, 2005, the Pension Plan was amended to freeze benefit plan accruals for participants. The investments in the Pension Plan are measured at fair value on a recurring basis each quarter using quoted market prices or the net asset value per share as a practical expedient. The projected benefit obligations associated with the Pension Plan are determined based on actuarial models utilizing mortality tables and discount rates applied to the expected benefit term. Restricted Cash Certain provisions of our debt agreements require us to maintain specified cash collateral balances. Amounts associated with these balances are considered to be restricted cash. Advertising and Search Revenues Effective April 1, 2020, certain of our advertising and search revenues are now presented within Roaming and other service revenues, resulting in a reclassification of $133 million of revenue for the three months ended March 31, 2020, and $120 million and $234 million for the three and six months ended June 30, 2019, respectively. These revenues were previously presented within Other revenues in our Condensed Consolidated Statements of Comprehensive Income. Prior periods have been reclassified to conform to current period presentation. Accounting Pronouncements Adopted During the Current Year Receivables and Expected Credit Losses In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” and has since modified the standard with several ASUs (collectively, the “new credit loss standard”). The new credit loss standard requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions and reasonable and supportable forecasts that affect the collectibility of the reported amount. The new credit loss standard became effective for us, and we adopted the standard, on January 1, 2020. The new credit loss standard required a cumulative-effect adjustment to Accumulated deficit at the date of initial application, and as a result, we did not restate prior periods presented in the condensed consolidated financial statements. Under the new credit loss standard we recognize lifetime expected credit losses at the inception of our credit risk exposures whereas we previously recognized credit losses only when it was probable that they had been incurred. We also recognize expected credit losses on our EIP receivables, which are inclusive of all installment receivables acquired in the Merger or issued thereafter, separately from, and in addition to, any unamortized discount on those receivables. Prior to the adoption of the new credit loss standard, we had offset our estimate of probable losses on our EIP receivables by the amount of the related unamortized discounts on those receivables. We have developed an expected credit loss model incorporating forward-looking loss indicators. The cumulative effect of initially applying the new credit loss standard on our receivables portfolio on January 1, 2020 was an increase to our allowance for credit losses of $91 million, a decrease to our net deferred tax liabilities of $24 million and an increase to our Accumulated deficit of $67 million. For EIP receivables acquired in the Merger, we also recognize expected credit losses separately from, and in addition, to the acquisition date fair value of the acquired EIP receivables. Accounts Receivable Portfolio Segment Accounts receivable consists primarily of amounts currently due from customers (e.g., for wireless services and monthly device lease payments), handset insurance administrators, wholesale partners, other carriers and third-party retail channels. Accounts receivable are presented in our Condensed Consolidated Balance Sheets at the amortized cost basis (i.e., the receivables’ outstanding principal balance adjusted for any write-offs), net of the allowance for expected credit losses. We have an arrangement to sell certain of our customer service accounts receivable on a revolving basis, which are treated as sales of financial assets. EIP Receivables Portfolio Segment We offer certain retail customers the option to pay for their devices and other purchases in installments, generally over a period of 24 months using an EIP. EIP receivables are presented in our Condensed Consolidated Balance Sheets at the amortized cost basis (i.e., the receivables’ outstanding principal balance adjusted for any write-offs and unamortized discounts), net of the allowance for expected credit losses. At the time of an installment sale, we impute a discount for interest if the EIP term exceeds 12 months as there is no stated rate of interest on the EIP receivables. The EIP receivables are recorded at their present value, which is determined by discounting expected future cash payments at the imputed interest rate. The difference between the recorded amount of the EIP receivables and their unpaid principal balance (i.e., the contractual amount due from the customer) results in a discount which is allocated to the performance obligations of the arrangement and recorded as a reduction in transaction price in Total service revenues and Equipment revenues in our Condensed Consolidated Statements of Comprehensive Income. We determine the imputed discount rate based primarily on current market interest rates and the estimated credit risk on the EIP receivables. The imputed discount on EIP receivables is amortized over the financed installment term using the effective interest method and recognized as Other revenues in our Condensed Consolidated Statements of Comprehensive Income. At the time that we originate EIP loans to customers, we recognize an allowance for credit losses that we expect to incur over the lifetime of such assets. This allowance represents the portion of the amortized cost basis of EIP receivables that we do not expect to collect. The current portion of the EIP receivables is included in Equipment installment plan receivables, net and the long-term portion of the EIP receivables is included in Equipment installment plan receivables due after one year, net in our Condensed Consolidated Balance Sheets. We have an arrangement to sell certain EIP receivables on a revolving basis, which are treated as sales of financial assets. Allowance for Credit Losses We maintain an allowance for expected credit losses and determine its appropriateness through an established process that assesses the lifetime credit losses that we expect to incur related to our receivable portfolio. We develop and document our allowance methodology at the portfolio segment level for the accounts receivable portfolio and EIP receivables portfolio segments. While we attribute portions of the allowance to our respective accounts receivable and EIP portfolio segments, the entire allowance is available to absorb expected credit losses related to the total receivable portfolio. Our process involves procedures to appropriately consider the unique risk characteristics of our accounts receivable and EIP receivable portfolio segments. For each portfolio segment, losses are estimated collectively for groups of receivables with similar characteristics. Our allowance levels are influenced by receivable volumes, receivable delinquency status, historical loss experience and other conditions influencing loss expectations, such as changes in credit and collections policies and forecasts of macro-economic conditions. Total imputed discount and allowances, which includes all accounts receivable and EIP receivables acquired in the Merger or issued thereafter, were approximately 7.8% and 7.0% of the total amount of gross accounts receivable, including EIP receivables, at June 30, 2020 and December 31, 2019, respectively. We consider a receivable past due when a customer has not paid us by the contractually specified payment due date. We write-off account balances if collection efforts are unsuccessful and the receivable balance is deemed uncollectible, based on customer credit quality and the aging of the receivable. Cloud Computing Arrangements In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract.” The standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The standard also requires the presentation of the amortization of the capitalized implementation costs in the same line item in the Condensed Consolidated Statements of Comprehensive Income as the fees associated with the hosting arrangement. The standard became effective for us, and we adopted the standard, on January 1, 2020. We adopted the standard on a prospective basis applying it to implementation costs incurred subsequent to January 1, 2020 and as a result did not restate the prior periods presented in the condensed consolidated financial statements. The adoption of the standard did not have a material impact on our condensed consolidated financial statements for the six months ended June 30, 2020. Income Taxes In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” The standard removes certain exceptions to the general principles in Topic 740. We early adopted the standard on January 1, 2020 and have applied the standard retrospectively to all periods presented. The adoption of this standard did not have an impact on our condensed consolidated financial statements. Guarantor Financial Information On March 2, 2020, the Securities and Exchange Commission (the “SEC”) adopted amendments to the financial disclosure requirements for guarantors and issuers of guaranteed securities, as well as for affiliates whose securities collateralize a registrant’s securities. The amendments revise Rules 3-10 and 3-16 of Regulation S-X, and relocate part of Rule 3-10 and all of Rule 3-16 to the new Article 13 in Regulation S-X, which is comprised of new Rules 13-01 and 13-02. We early adopted the requirements of the amendments on January 1, 2020, which included replacing guarantor condensed consolidating financial information with summarized financial information for the consolidated obligor group (Parent, Issuer, and Guarantor Subsidiaries) as well as no longer requiring guarantor cash flow information, financial information for non-guarantor subsidiaries, and a reconciliation to the consolidated results. Accounting Pronouncements Not Yet Adopted Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not have, or are not expected to have, a significant impact on our present or future condensed consolidated financial statements.

The unaudited condensed consolidated financial statements of T-Mobile US, Inc. (“T-Mobile,” “we,” “our,” “us” or the “Company”) include all adjustments of a normal recurring nature necessary for the fair presentation of the results for the interim periods presented. The results for the interim periods are not necessarily indicative of those for the full year. The condensed consolidated financial statements should be read in conjunction with our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019.

On April 29, 2018, we entered into a Business Combination Agreement (the “Business Combination Agreement”) to merge with Sprint Corporation (“Sprint”) in an all-stock transaction at a fixed exchange ratio of 0.10256 shares of T-Mobile common stock for each share of Sprint common stock, or 9.75 shares of Sprint common stock for each share of T-Mobile common stock (the “Merger”). On April 1, 2020, we completed the Merger and acquired Sprint (see Note 2 - Business Combination).

On July 26, 2019, pursuant to the requirement as set forth in the U.S. Department of Justice’s (the “DOJ”) complaint and proposed final judgement (the “Consent Decree), T-Mobile entered into an Asset Purchase Agreement (the “Asset Purchase Agreement”) with Sprint and DISH Network Corporation (“DISH”). Pursuant to the Asset Purchase Agreement and upon the terms and subject to the conditions thereof, on July 1, 2020 DISH acquired the prepaid wireless business operated under the Boost Mobile and Sprint prepaid brands (excluding the Assurance brand Lifeline customers and the prepaid wireless customers of Shenandoah Telecommunications Company and Swiftel Communications, Inc.), including customer accounts, inventory, contracts, intellectual property and certain other specified assets (the “Prepaid Business”) and assumed certain related liabilities (the “Prepaid Transaction”). Upon closing of the Prepaid Transaction, we received $1.4 billion from DISH, subject to a working capital adjustment.

The condensed consolidated financial statements include the balances and results of operations of T-Mobile and our consolidated subsidiaries. We consolidate majority-owned subsidiaries over which we exercise control, as well as variable interest entities (“VIEs”) where we are deemed to be the primary beneficiary and VIEs which cannot be deconsolidated, such as those related to our obligations to pay for the management and operation of certain of our wireless communications tower sites. Intercompany transactions and balances have been eliminated in consolidation.

The preparation of financial statements in conformity with United States (“U.S.”) generally accepted accounting principles (“GAAP”) requires our management to make estimates and assumptions which affect the financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and other assumptions which our management believes are reasonable under the circumstances, including but not limited to the valuation of assets acquired and liabilities assumed through the Merger with Sprint and the potential impacts arising from the COVID-19 pandemic. These estimates are inherently subject to judgment and actual results could differ from those estimates.

Through the Merger, the Company acquired lease agreements (the “Agreements”) with various educational and non-profit institutions that provide us with the right to use Federal Communications Commission (“FCC”) spectrum licenses (Educational Broadband Services or “EBS spectrum”) in the 2.5 GHz band. In addition to the Agreements with educational institutions and private owners who hold the license, the Company also acquired direct ownership of spectrum licenses previously acquired by Sprint through government auctions or other acquisitions.

The Agreements with educational and certain non-profit institutions are typically for five to ten years with automatic renewal provisions, bringing the total term of the agreement up to 30 years. Majority of the Agreements include a right of first refusal to acquire, lease or otherwise use the license at the end of the two automatic renewal periods.

Leased FCC spectrum licenses are recorded as executory contracts whereby, as a result of business combination accounting, an intangible asset or liability is recorded reflecting the extent to which contractual terms are favorable or unfavorable to current market rates. These intangible assets or liabilities are amortized over the estimated remaining useful life of the lease agreements. Contractual lease payments are recognized on a straight-line basis over the remaining term of the arrangement, including renewals, and are presented in Costs of services within our Condensed Consolidated Statements of Comprehensive Income.

The Agreements enhance the value of the Company’s owned spectrum licenses as the collective value is higher than the value of individual bands of spectrum within a specific geography. This value is derived from the ability to provide wireless service to customers across large geographic areas and maintain the same or similar wireless connectivity quality. This enhanced value from combining owned and leased spectrum licenses to create contiguous spectrum is referred to as an aggregation premium.

The supply chain and inventory management arrangement includes, among other things, that Brightstar may purchase inventory from the original equipment manufacturers (“OEM”) to sell directly to our indirect dealers. As compensation for these services, we remit per unit fees to Brightstar for each device sold to these indirect dealers.

Devices sold from T-Mobile to Brightstar do not meet the criteria for a sale, as control is not transferred until devices are sold through to indirect dealers, and in some cases, end customers. Devices transferred from T-Mobile to Brightstar remain in inventory until control is transferred to the indirect dealers or end customers.

For service subscribers who choose to lease a device previously sold to the dealer, T-Mobile will repurchase the device from the dealer and originate a lease directly with the service subscriber. Repurchase activity from the dealer is estimated and treated as a right of return, reducing equipment revenue at the time of sale to the dealer. Upon lease to the end customer, T-Mobile recognizes lease revenue over the associated lease term within Equipment revenues in our Condensed Consolidated Statements of Comprehensive Income.

Through the Merger, we acquired device lease contracts in which Sprint is the lessor, substantially all of which are classified as operating leases, and the associated fixed assets. These leased devices were recorded as fixed assets at their acquisition date fair value and presented within Property and equipment, net on our Condensed Consolidated Balance Sheets. These devices are depreciated using the group method over the estimated remaining useful life to their estimated residual value. The estimated useful life reflects the period for which we estimate the group of leased devices will provide utility to us, which may be longer than the initial lease term based on customer options in the Sprint Flex Lease program to renew the lease on a month-to-month basis after the initial lease term concludes. Revenues associated with the leased wireless devices, net of lease incentives, are generally recognized straight-line over the lease term.

T-Mobile depreciates leased devices on a group basis using the straight-line method over the estimated useful life of the device, which considers the lease term (e.g., 18 months and month-to-month renewal options for the Sprint Flex Lease program), trade-in activity and write-offs for lost and stolen devices. Lost and stolen devices are incorporated into the estimates of depreciation expense and recognized as an adjustment to accumulated depreciation when the loss event occurs. The Company’s policy using the group method of depreciation has been applied to acquired leased devices as well as leases originated subsequent to the Merger close. Acquired leased devices are grouped based on the age of the device.

Upon device upgrade or at lease end, customers in the Jump on Demand lease program must return or purchase their device. Customers in the Sprint Flex Lease program have the option to return or purchase their device or to renew their lease on a month-to-month basis at the end of the lease term. Returned devices are transferred from Property and equipment, net to Inventory on our Condensed Consolidated Balance Sheets and are valued at the lower of cost or net realizable value, with any write-down recognized as Cost of equipment sales in our Condensed Consolidated Statements of Comprehensive Income.

T-Mobile capitalizes postpaid sales commissions for service activation as costs to acquire a contract and amortizes them over 24 months. Prepaid commissions are expensed as incurred as their estimated period of benefit does not extend beyond 12 months. Commissions paid upon device upgrade are not capitalized if a customer contract is less than one year. Commissions paid when the customer has a lease are treated as initial direct costs and recognized over the lease term.

T-Mobile records the effects of financing on all equipment installment plan (“EIP”) loans regardless as to whether the financing is considered to be significant or not. The imputation of interest results in a discount of the EIP receivable thereby adjusting the transaction price of the contract with the customer, which is then allocated to the performance obligations of the arrangement.

For indirect channel loans to the end service customer in which the sale of the device was to the dealer (sell-in basis), the effect of imputing interest is recognized as a reduction to service revenue, the only performance obligation with the service customer as the device sale was recognized when transferred to the dealer, and over the service contract period.

Prior to the Merger, Sprint entered into a lease-out and leaseback agreement with a tower operator (Global Signal, Inc. a third party that was subsequently acquired by Crown Castle International Corp. (“CCI”)). The tower operator was granted exclusive rights to lease 6,600 communications towers (lease-out) for 32 years, which were originally constructed by Sprint on land that Sprint leased from individual landowners. Sprint received upfront proceeds in 2005 of $1.2 billion and obtained the right to use a portion of the space on the towers with a stipulated monthly payment (leaseback), generally with a 10-year initial term with five-year renewal options.

The arrangement is accounted for as a financing with the cell towers owned by Sprint included in Property and equipment and a financing obligation for the amounts contractually due to CCI included in Tower obligations in our Condensed Consolidated Balance Sheets. The tower assets are depreciated to their estimated residual value and payments to CCI are recognized as interest expense and a reduction to the financing obligation. See Note 9 – Tower Obligati ons for further information on this arrangement.

Performance obligations related to our Wireline customers involve the provision of services to corporate customers. Wireline service performance obligations are typically satisfied over a period between 24 and 36 months. Amounts due for services are invoiced and collected periodically over the relevant service period. Wireline contracts are not subject to significant amounts of variable consideration, other than charges intended to partially recover taxes imposed on the Company, including fees related to the Universal Service Fund. Such fees are based on the customer's monthly usage and are therefore included in the corresponding distinct months of Wireline services. Our Wireline contracts do provide the customer with monthly options to

Through the Merger, we acquired the assets and assumed the liabilities associated with the Sprint Retirement Pension Plan (the “Pension Plan”), which is a defined benefit pension plan providing postretirement benefits to certain employees. As of December 31, 2005, the Pension Plan was amended to freeze benefit plan accruals for participants.

The investments in the Pension Plan are measured at fair value on a recurring basis each quarter using quoted market prices or the net asset value per share as a practical expedient. The projected benefit obligations associated with the Pension Plan are determined based on actuarial models utilizing mortality tables and discount rates applied to the expected benefit term.

Effective April 1, 2020, certain of our advertising and search revenues are now presented within Roaming and other service revenues, resulting in a reclassification of $133 million of revenue for the three months ended March 31, 2020, and $120 million and $234 million for the three and six months ended June 30, 2019, respectively. These revenues were previously presented within Other revenues in our Condensed Consolidated Statements of Comprehensive Income. Prior periods have been reclassified to conform to current period presentation.

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” and has since modified the standard with several ASUs (collectively, the “new credit loss standard”). The new credit loss standard requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions and reasonable and supportable forecasts that affect the collectibility of the reported amount. The new credit loss standard became effective for us, and we adopted the standard, on January 1, 2020. The new credit loss standard required a cumulative-effect adjustment to Accumulated deficit at the date of initial application, and as a result, we did not restate prior periods presented in the condensed consolidated financial statements.

Under the new credit loss standard we recognize lifetime expected credit losses at the inception of our credit risk exposures whereas we previously recognized credit losses only when it was probable that they had been incurred. We also recognize expected credit losses on our EIP receivables, which are inclusive of all installment receivables acquired in the Merger or issued thereafter, separately from, and in addition to, any unamortized discount on those receivables. Prior to the adoption of the new credit loss standard, we had offset our estimate of probable losses on our EIP receivables by the amount of the related unamortized discounts on those receivables. We have developed an expected credit loss model incorporating forward-looking loss indicators. The cumulative effect of initially applying the new credit loss standard on our receivables portfolio on January 1, 2020 was an increase to our allowance for credit losses of $91 million, a decrease to our net deferred tax liabilities of $24 million and an increase to our Accumulated deficit of $67 million.

Accounts receivable consists primarily of amounts currently due from customers (e.g., for wireless services and monthly device lease payments), handset insurance administrators, wholesale partners, other carriers and third-party retail channels. Accounts receivable are presented in our Condensed Consolidated Balance Sheets at the amortized cost basis (i.e., the receivables’ outstanding principal balance adjusted for any write-offs), net of the allowance for expected credit losses. We have an arrangement to sell certain of our customer service accounts receivable on a revolving basis, which are treated as sales of financial assets.

We offer certain retail customers the option to pay for their devices and other purchases in installments, generally over a period of 24 months using an EIP. EIP receivables are presented in our Condensed Consolidated Balance Sheets at the amortized cost basis (i.e., the receivables’ outstanding principal balance adjusted for any write-offs and unamortized discounts), net of the allowance for expected credit losses. At the time of an installment sale, we impute a discount for interest if the EIP term exceeds 12 months as there is no stated rate of interest on the EIP receivables. The EIP receivables are recorded at their present value, which is determined by discounting expected future cash payments at the imputed interest rate. The difference between the recorded amount of the EIP receivables and their unpaid principal balance (i.e., the contractual amount due from the customer) results in a discount which is allocated to the performance obligations of the arrangement and recorded as a reduction in transaction price in Total service revenues and Equipment revenues in our Condensed Consolidated Statements of Comprehensive Income. We determine the imputed discount rate based primarily on current market interest rates and the estimated credit risk on the EIP receivables. The imputed discount on EIP receivables is amortized over the financed installment term using the effective interest method and recognized as Other revenues in our Condensed Consolidated Statements of Comprehensive Income.

The current portion of the EIP receivables is included in Equipment installment plan receivables, net and the long-term portion of the EIP receivables is included in Equipment installment plan receivables due after one year, net in our Condensed Consolidated Balance Sheets. We have an arrangement to sell certain EIP receivables on a revolving basis, which are treated as sales of financial assets.

We maintain an allowance for expected credit losses and determine its appropriateness through an established process that assesses the lifetime credit losses that we expect to incur related to our receivable portfolio. We develop and document our allowance methodology at the portfolio segment level for the accounts receivable portfolio and EIP receivables portfolio segments. While we attribute portions of the allowance to our respective accounts receivable and EIP portfolio segments, the entire allowance is available to absorb expected credit losses related to the total receivable portfolio.

Our process involves procedures to appropriately consider the unique risk characteristics of our accounts receivable and EIP receivable portfolio segments. For each portfolio segment, losses are estimated collectively for groups of receivables with similar characteristics. Our allowance levels are influenced by receivable volumes, receivable delinquency status, historical loss experience and other conditions influencing loss expectations, such as changes in credit and collections policies and forecasts of macro-economic conditions.

Total imputed discount and allowances, which includes all accounts receivable and EIP receivables acquired in the Merger or issued thereafter, were approximately 7.8% and 7.0% of the total amount of gross accounts receivable, including EIP receivables, at June 30, 2020 and December 31, 2019, respectively.

In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract.” The standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The standard also requires the presentation of the amortization of the capitalized implementation costs in the same line item in the Condensed Consolidated Statements of Comprehensive Income as the fees associated with the hosting arrangement. The standard became effective for us, and we adopted the standard, on January 1, 2020. We adopted the standard on a prospective basis applying it to implementation costs incurred subsequent to January 1, 2020 and as a result did not restate the prior periods presented in the condensed consolidated financial statements. The adoption of the standard did not have a material impact on our condensed consolidated financial statements for the six months ended June 30, 2020.

In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” The standard removes certain exceptions to the general principles in Topic 740. We early adopted the standard on January 1, 2020 and have applied the standard retrospectively to all periods presented. The adoption of this standard did not have an impact on our condensed consolidated financial statements.

On March 2, 2020, the Securities and Exchange Commission (the “SEC”) adopted amendments to the financial disclosure requirements for guarantors and issuers of guaranteed securities, as well as for affiliates whose securities collateralize a registrant’s securities. The amendments revise Rules 3-10 and 3-16 of Regulation S-X, and relocate part of Rule 3-10 and all of Rule 3-16 to the new Article 13 in Regulation S-X, which is comprised of new Rules 13-01 and 13-02. We early adopted the requirements of the amendments on January 1, 2020, which included replacing guarantor condensed consolidating financial information with summarized financial information for the consolidated obligor group (Parent, Issuer, and Guarantor Subsidiaries) as well as no longer requiring guarantor cash flow information, financial information for non-guarantor subsidiaries, and a reconciliation to the consolidated results.

Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not have, or are not expected to have, a significant impact on our present or future condensed consolidated financial statements.