Tower Obligations - Future Minimum Payments (Details) $ in Millions |
Dec. 31, 2020
USD ($)
|
|---|---|
| Leases [Abstract] | |
| Tower obligation payments, due 2021 | $ 397 |
| Tower obligation payments, due 2022 and 2023 | 716 |
| Tower obligation payment, due 2024 and 2025 | 598 |
| Tower obligation payments due thereafter | $ 624 |