Device Upgrade Period

No definition available.

Name:	tmus_DeviceUpgradePeriod
Namespace Prefix:	tmus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Equipment Installment Plan, Payment Term

+ References

No definition available.

+ Details

Name:	tmus_EquipmentInstallmentPlanPaymentTerm
Namespace Prefix:	tmus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Licenses Issued, Fixed Period

+ References

No definition available.

+ Details

Name:	tmus_LicensesIssuedFixedPeriod
Namespace Prefix:	tmus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Spectrum Leasing, Lease Term

+ References

No definition available.

+ Details

Name:	tmus_SpectrumLeasingLeaseTerm
Namespace Prefix:	tmus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Spectrum Leasing, Total Lease Term

+ References

No definition available.

+ Details

Name:	tmus_SpectrumLeasingTotalLeaseTerm
Namespace Prefix:	tmus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-SubTopic 35
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

+ Details

Name:	us-gaap_AdvertisingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortization period of cost capitalized in obtaining or fulfilling contract with customer, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131251-203054

+ Details

Name:	us-gaap_CapitalizedContractCostAmortizationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of excise and sales taxes included in sales and revenues, which are then deducted as a cost of sales. Includes excise taxes, which are applied to specific types of transactions or items (such as gasoline or alcohol); and sales, use and value added taxes, which are applied to a broad class of revenue-producing transactions involving a wide range of goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportingUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=tmus_SprintCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=tmus_SpectrumLicensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TransactionTypeAxis=tmus_EIPSecuritizationArrangementMember
Namespace Prefix:
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Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) customer	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Device upgrade period	18 months
Number of reporting units \| customer	1
Federal Universal Service Fund and other fees	$ 216	$ 267	$ 93
Average amortization period, deferred contract costs (in months)	24 months
Advertising expense	$ 2,200	$ 1,800	$ 1,600
Sprint
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total term of agreement	30 years
Sprint \| Spectrum Licenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Fixed period	15 years
Minimum \| Sprint
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Agreements with educational and certain non-profit institutions, term	5 years
Maximum \| Sprint
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Agreements with educational and certain non-profit institutions, term	10 years
EIP Securitization Arrangement \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equipment installment plan, maximum payment term	24 months