Additional Financial Information - Schedule of Related Party Transactions (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Accounts Payable and Accrued Liabilities [Line Items] | |||
| Dividends on common stock | $ 3,300 | $ 747 | $ 0 |
| 2023-2024 Stockholder Return Program | |||
| Accounts Payable and Accrued Liabilities [Line Items] | |||
| Dividends on common stock | 3,300 | 747 | |
| 2023-2024 Stockholder Return Program | DT | |||
| Accounts Payable and Accrued Liabilities [Line Items] | |||
| Dividends on common stock | 1,700 | 393 | |
| Affiliates | |||
| Accounts Payable and Accrued Liabilities [Line Items] | |||
| Fees incurred for use of the T-Mobile brand | 80 | 80 | 80 |
| International long distance agreement | 19 | 20 | 25 |
| Reimbursement of certain administrative expenses | $ 4 | $ 4 | $ 4 |