Intangible Assets - Definite-Lived Intangible Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Finite-Lived Intangible Assets | ||
| Gross carrying value | $ 976 | $ 976 |
| Accumulated amortization | (873) | (862) |
| Marketing agreements | ||
| Finite-Lived Intangible Assets | ||
| Gross carrying value | 730 | 730 |
| Accumulated amortization | (692) | (687) |
| Contracts | ||
| Finite-Lived Intangible Assets | ||
| Gross carrying value | 193 | 193 |
| Accumulated amortization | (128) | (122) |
| Other | ||
| Finite-Lived Intangible Assets | ||
| Gross carrying value | 53 | 53 |
| Accumulated amortization | $ (53) | $ (53) |