Asset Acquisition, Noncash Consideration Transferred

No definition available.

Name:	tmus_AssetAcquisitionNoncashConsiderationTransferred
Namespace Prefix:	tmus_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increase (Decrease) to Cash Tax Liability

+ References

No definition available.

+ Details

Name:	tmus_IncreaseDecreaseToCashTaxLiability
Namespace Prefix:	tmus_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

License Purchase Agreement, Minimum Period

+ References

No definition available.

+ Details

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

- Definition

Amount of consideration transferred in asset acquisition. Includes, but is not limited to, cash, liability incurred by acquirer, and equity interest issued by acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 55
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479908/805-50-55-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480060/805-50-25-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 30
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480027/805-50-30-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 30
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480027/805-50-30-2

+ Details

Name:	us-gaap_AssetAcquisitionConsiderationTransferred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of contingent consideration recognized as part of consideration transferred in asset acquisition.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480060/805-50-25-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 30
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480027/805-50-30-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 30
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480027/805-50-30-2

+ Details

Name:	us-gaap_AssetAcquisitionConsiderationTransferredContingentConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of assets held-for-sale that are not part of a disposal group.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482309/360-10-15-4

+ Details

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment in the future.

+ References

+ Details

Name:	us-gaap_DepositsAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

+ Details

Name:	us-gaap_GainLossOnDispositionOfAssets1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-3

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 38
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-38

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 31
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-31

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-31

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-14

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-14

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479876/805-20-55-14

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Name Accounting Standards Codification
-Section 55
-Paragraph 40
-SubTopic 30
-Topic 350
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482640/350-30-55-40

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482686/350-30-45-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-2

+ Details

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

- Definition

Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the capitalized costs to acquire rights under a license arrangement (for example, to sell specified products in a specified territory) having an indefinite period of benefit.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(15))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-6

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-2

+ Details

Name:	us-gaap_IndefiniteLivedLicenseAgreements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow to acquire asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_AssetAcquisitionAxis=tmus_SpectrumAuctionLicensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	tmus_TypeOfExchangeAxis=tmus_SpectrumExchangeTransactionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AssetAcquisitionAxis=tmus_NonCashSpectrumLicenseAcquisitionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=tmus_ComcastCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=tmus_GrainManagementLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementOfFinancialPositionLocationBalanceAxis=us-gaap_OtherAssetsCurrent
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementOfFinancialPositionLocationBalanceAxis=us-gaap_OtherAssetsNoncurrent
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

Spectrum License Transactions - Narrative (Details) - USD ($) $ in Millions							1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 24, 2026	Jul. 10, 2026	Jun. 02, 2026	May 30, 2025	Jan. 13, 2025	Sep. 12, 2023	Jun. 30, 2026	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Apr. 30, 2026	Dec. 31, 2025
Indefinite-lived Intangible Assets [Line Items]
Purchase of spectrum licenses								$ 484	$ 842	$ 510	$ 915
Spectrum licenses							$ 98,178	98,178		98,178			$ 98,032
Spectrum Auction Licenses
Indefinite-lived Intangible Assets [Line Items]
Consideration transferred							278
Deposits assets							25	25		25		$ 25
Spectrum Auction Licenses \| Subsequent Event
Indefinite-lived Intangible Assets [Line Items]
Purchase of spectrum licenses		$ 31
Licensing Agreements \| Spectrum Exchange Transactions
Indefinite-lived Intangible Assets [Line Items]
Spectrum licenses held-for-sale							486	486		486			$ 3
Gain on spectrum exchange transactions								22	1	24	13
Licensing Agreements \| Non-Cash Spectrum License Acquisitions \| Spectrum Exchange Transactions
Indefinite-lived Intangible Assets [Line Items]
Consideration transferred, exchange of licenses								43	$ 1	48	$ 173
Licensing Agreements \| Comcast Corporation
Indefinite-lived Intangible Assets [Line Items]
Consideration transferred			$ 46
License purchase agreement, minimum period before termination allowed						2 years
Licensing Agreements \| Grain Management, LLC \| Spectrum Licenses
Indefinite-lived Intangible Assets [Line Items]
Total cash consideration				$ 2,900
Spectrum licenses							3,600	3,600		3,600
Increase our cash tax liability				$ 850
Licensing Agreements \| Grain Management, LLC \| Spectrum Licenses \| Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent
Indefinite-lived Intangible Assets [Line Items]
Spectrum licenses held-for-sale							2,900	2,900		2,900
Licensing Agreements \| Grain Management, LLC \| Spectrum Licenses \| Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent
Indefinite-lived Intangible Assets [Line Items]
Spectrum licenses held-for-sale							$ 690	$ 690		$ 690
Spectrum Auction Licenses \| Subsequent Event
Indefinite-lived Intangible Assets [Line Items]
Purchase of spectrum licenses	$ 222
Minimum \| Licensing Agreements \| Comcast Corporation
Indefinite-lived Intangible Assets [Line Items]
Total cash consideration					$ 1,200	$ 1,200
Minimum \| Optional Sale Licenses \| Comcast Corporation
Indefinite-lived Intangible Assets [Line Items]
Total cash consideration						2,100
Maximum \| Licensing Agreements \| Comcast Corporation
Indefinite-lived Intangible Assets [Line Items]
Total cash consideration					$ 3,400	$ 3,300