Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2024
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, 2023. 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”) for which 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 that affect the financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and other assumptions that management believes are reasonable under the circumstances. Estimates are inherently subject to judgment and actual results could differ from those estimates. Foreign Currency Transactions On May 8, 2024, we issued €2.0 billion of euro (“EUR”) denominated debt. T-Mobile’s functional currency is the U.S. dollar (“USD”). Each period, we convert activity and balances in EUR into USD using average exchange rates for the period for income statement amounts and using end-of-period or spot exchange rates for assets and liabilities. We record transaction gains and losses resulting from the conversion of transaction currency to functional currency as a component of Other (expense) income, net on our Condensed Consolidated Statements of Comprehensive Income. Derivative and Hedging Instruments The Company manages its exposure to foreign exchange rates and interest rates through a risk management program that includes the use of derivative financial instruments, including cross-currency swaps. We designate certain derivatives as accounting hedge relationships. We do not hold derivatives for trading or speculative purposes. We record derivatives on our Condensed Consolidated Balance Sheets and recognize them as either assets or liabilities at fair value. Fair value is derived primarily from observable market data, and our derivatives are classified as Level 2 in the fair value hierarchy. Cash flows associated with qualifying hedge derivative instruments are presented in the same category on our Condensed Consolidated Statements of Cash Flows as the item being hedged. For fair value hedges, other than foreign currency hedges, the change in the fair value of the derivative instruments is recognized in earnings through the same income statement line item as the change in the fair value of the hedged item. For cash flow hedges, as well as fair value foreign currency hedges, the change in the fair value of the derivative instruments is reported in Accumulated other comprehensive loss and recognized in earnings when the hedged item is recognized in earnings, again, through the same income statement line item. Accounting Pronouncements Not Yet Adopted Segment Reporting Disclosures In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” The standard expands reportable segment disclosure requirements for public business entities primarily through enhanced disclosures about significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit (referred to as the “significant expense principle”). The standard will become effective for us for our fiscal year 2024 annual financial statements and interim financial statements thereafter and will be applied retrospectively for all prior periods presented in the financial statements, with early adoption permitted. We plan to adopt the standard when it becomes effective for us beginning in our fiscal year 2024 annual financial statements. We are currently evaluating the impact this guidance will have on the disclosures included in the Notes to the Consolidated Financial Statements. Income Tax Disclosures In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” The standard enhances income tax disclosure requirements for all entities by requiring specified categories and greater disaggregation within the rate reconciliation table, disclosure of income taxes paid by jurisdiction, and providing clarification on uncertain tax positions and related financial statement impacts. The standard will be effective for us for our fiscal year 2025 annual financial statements with early adoption permitted. We plan to adopt the standard when it becomes effective for us beginning in our fiscal year 2025 annual financial statements, and we expect the adoption of the standard will impact certain of our income tax disclosures in the Notes to the 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, 2023.

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”) for which 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 that affect the financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and other assumptions that management believes are reasonable under the circumstances. Estimates are inherently subject to judgment and actual results could differ from those estimates.

On May 8, 2024, we issued €2.0 billion of euro (“EUR”) denominated debt. T-Mobile’s functional currency is the U.S. dollar (“USD”). Each period, we convert activity and balances in EUR into USD using average exchange rates for the period for income statement amounts and using end-of-period or spot exchange rates for assets and liabilities. We record transaction gains and losses resulting from the conversion of transaction currency to functional currency as a component of Other (expense) income, net on our Condensed Consolidated Statements of Comprehensive Income.

The Company manages its exposure to foreign exchange rates and interest rates through a risk management program that includes the use of derivative financial instruments, including cross-currency swaps. We designate certain derivatives as accounting hedge relationships. We do not hold derivatives for trading or speculative purposes.

We record derivatives on our Condensed Consolidated Balance Sheets and recognize them as either assets or liabilities at fair value. Fair value is derived primarily from observable market data, and our derivatives are classified as Level 2 in the fair value hierarchy.

Cash flows associated with qualifying hedge derivative instruments are presented in the same category on our Condensed Consolidated Statements of Cash Flows as the item being hedged. For fair value hedges, other than foreign currency hedges, the change in the fair value of the derivative instruments is recognized in earnings through the same income statement line item as the change in the fair value of the hedged item. For cash flow hedges, as well as fair value foreign currency hedges, the change in the fair value of the derivative instruments is reported in Accumulated other comprehensive loss and recognized in earnings when the hedged item is recognized in earnings, again, through the same income statement line item.

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” The standard expands reportable segment disclosure requirements for public business entities primarily through enhanced disclosures about significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit (referred to as the “significant expense principle”). The standard will become effective for

us for our fiscal year 2024 annual financial statements and interim financial statements thereafter and will be applied retrospectively for all prior periods presented in the financial statements, with early adoption permitted. We plan to adopt the standard when it becomes effective for us beginning in our fiscal year 2024 annual financial statements. We are currently evaluating the impact this guidance will have on the disclosures included in the Notes to the Consolidated Financial Statements.

In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” The standard enhances income tax disclosure requirements for all entities by requiring specified categories and greater disaggregation within the rate reconciliation table, disclosure of income taxes paid by jurisdiction, and providing clarification on uncertain tax positions and related financial statement impacts. The standard will be effective for us for our fiscal year 2025 annual financial statements with early adoption permitted. We plan to adopt the standard when it becomes effective for us beginning in our fiscal year 2025 annual financial statements, and we expect the adoption of the standard will impact certain of our income tax disclosures in the Notes to the Consolidated Financial Statements.