Commitments and Contingencies - Narrative (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2020
USD ($)
| |
| Operating Leased Assets [Line Items] | |
| Purchase commitment, due 2021 | $ 5,000 |
| Purchase commitment, due 2022 and 2023 | 4,500 |
| Purchase commitment, due 2024 and 2025 | 2,400 |
| Purchase commitment, due thereafter | 1,700 |
| Lease and service credit commitment, due 2021 | 338 |
| Lease and service credit commitment, due 2022 and 2023 | 675 |
| Lease and service credit commitment, due 2024 and 2025 | 594 |
| Lease and service credit commitment, due thereafter | 5,100 |
| Maximum remaining commitment | 92 |
| Merger commitment, due 2021 | 23 |
| Merger commitment, due in 2022 and 2023 | 37 |
| Merger commitment, due in 2024 and 2025 | $ 13 |
| Minimum | |
| Operating Leased Assets [Line Items] | |
| Commitment term | 15 years |
| Maximum | |
| Operating Leased Assets [Line Items] | |
| Commitment term | 30 years |