Derivatives - Cumulative Basis Adjustment for Fair Value Hedges (Details) - Fair value hedges - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Derivatives | ||
| Hedged Liability, Fair Value Hedge | $ 598 | $ 1,274 |
| Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) | 11 | 22 |
| Short-term borrowings and current portion of long-term debt | ||
| Derivatives | ||
| Hedged Liability, Fair Value Hedge | 373 | 499 |
| Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) | 5 | |
| Long-term debt | ||
| Derivatives | ||
| Hedged Liability, Fair Value Hedge | 225 | 775 |
| Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) | $ 6 | $ 22 |