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.

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=tmus_SeniorNotesDue20224.000Member
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Name:	us-gaap_DebtInstrumentAxis=tmus_SeniorNotesDue20255.125Member
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Guarantor Financial Information Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2017	Mar. 16, 2017	Jan. 31, 2017	Jan. 25, 2017
Incremental Term Loan Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt			$ 4,000
Refinanced Secured Term Loans [Member]
Condensed Financial Statements, Captions [Line Items]
Secured debt			$ 1,980	$ 1,980
4.000% Senior Notes Due 2022 [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt		$ 500
Interest rate, stated percentage		4.00%
4.000% Senior Notes Due 2022 [Member] \| Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt	$ 500
Interest rate, stated percentage	4.00%
5.125% Senior Notes due 2025 [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt		$ 500
Interest rate, stated percentage		5.125%
5.125% Senior Notes due 2025 [Member] \| Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt	$ 500
Interest rate, stated percentage	5.125%
5.375% Senior Notes Due 2027 [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt		$ 500
Interest rate, stated percentage		5.375%
5.375% Senior Notes Due 2027 [Member] \| Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt	$ 500
Interest rate, stated percentage	5.375%