Leases - Cash Flow From Lease Transactions (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Cash paid for amounts included in the measurement of lease liabilities | |||
| Operating cash outflows from finance leases | $ 8 | $ 8 | $ 7 |
| Financing cash outflows from finance leases | 42 | 25 | 4 |
| Operating cash outflows from operating leases | 1,135 | 1,212 | 1,154 |
| ROU assets obtained in exchange for new finance lease liabilities | 46 | 50 | 68 |
| ROU assets obtained in exchange for new operating lease liabilities | $ 779 | $ 785 | 5,102 |
| ROU assets obtained in exchange for new operating lease liabilities - post adoption | $ 1,383 | ||