Condensed Consolidated Statement of Stockholders' Equity (Parenthetical) $ in Millions	6 Months Ended
Jun. 30, 2020 USD ($)
Par Value and Additional Paid-in Capital
Payment received to facilitate SoftBank Monetization	$ 300

Master Framework Agreement, Proceeds Received to Facilitate Stock Transaction

No definition available.

Name:	tmus_MasterFrameworkAgreementProceedsReceivedToFacilitateStockTransaction
Namespace Prefix:	tmus_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration