v3.22.0.1
Additional Financial Information - Related Party Transactions (Details) - USD ($)
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Aug. 23, 2021
Accounts Payable and Accrued Liabilities [Line Items]        
Principal Amount $ 1,234,000,000      
Affiliates        
Accounts Payable and Accrued Liabilities [Line Items]        
Discount related to roaming expenses (2,000,000) $ (5,000,000) $ (9,000,000)  
Fees incurred for use of the T-Mobile brand 80,000,000 83,000,000 88,000,000  
International long distance agreement 37,000,000 47,000,000 39,000,000  
Reimbursement of certain administrative expenses 5,000,000 $ 6,000,000 $ 11,000,000  
Senior Notes | Affiliates        
Accounts Payable and Accrued Liabilities [Line Items]        
Principal Amount $ 1,000,000,000      
4.500% Senior Notes due 2026        
Accounts Payable and Accrued Liabilities [Line Items]        
Interest rate, stated percentage 4.50%      
4.500% Senior Notes due 2026 | Affiliates        
Accounts Payable and Accrued Liabilities [Line Items]        
Interest rate, stated percentage 4.50%      
4.500% Senior Notes due 2026 | Senior Notes        
Accounts Payable and Accrued Liabilities [Line Items]        
Principal Amount $ 1,000,000,000      
4.500% Senior Notes due 2026 | Senior Notes | Affiliates        
Accounts Payable and Accrued Liabilities [Line Items]        
Principal Amount $ 1,000,000,000     $ 1,000,000,000
Interest rate, stated percentage       4.50%