Goodwill, Spectrum License Transactions and Other Intangible Assets - Schedule of Fair Value of Intangible Assets Acquired in the Sprint Merger (Details) - Sprint $ in Millions |
Apr. 01, 2020
USD ($)
|
|---|---|
| Finite-Lived Intangible Assets [Line Items] | |
| Total intangible assets acquired | $ 51,680 |
| Tradenames | |
| Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Useful Life (in years) | 2 years |
| Finite-lived, fair value | $ 207 |
| Customer relationships | |
| Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Useful Life (in years) | 8 years |
| Finite-lived, fair value | $ 4,900 |
| Favorable spectrum leases | |
| Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Useful Life (in years) | 18 years |
| Finite-lived, fair value | $ 745 |
| Other intangible assets | |
| Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Useful Life (in years) | 7 years |
| Finite-lived, fair value | $ 428 |
| Spectrum Licenses | |
| Finite-Lived Intangible Assets [Line Items] | |
| Indefinite-lived, Fair Value (in millions) | $ 45,400 |