Derivative Financial Instruments - Cumulative Basis Adjustments for Fair Value Hedges (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Short-term debt | ||
| Amounts recorded in the Consolidated Statement of Financial Position related to cumulative basis adjustments for fair value hedges | ||
| Carrying amount of the hedged item | $ (1,878) | |
| Cumulative hedging adjustments included in the carrying amount-assets/(liabilities) | (4) | |
| Hedging adjustments on discontinued hedging relationships | (6) | |
| Long-term debt | ||
| Amounts recorded in the Consolidated Statement of Financial Position related to cumulative basis adjustments for fair value hedges | ||
| Carrying amount of the hedged item | $ (3,411) | (6,004) |
| Cumulative hedging adjustments included in the carrying amount-assets/(liabilities) | (440) | (333) |
| Hedging adjustments on discontinued hedging relationships | $ (404) | $ (213) |