Leases - Lease Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Leases [Abstract] | ||
| Other current liabilities | $ (60) | $ (62) |
| Other non-current liabilities | (177) | (176) |
| Total | $ 237 | $ 238 |
| Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] | us-gaap:OtherLiabilitiesCurrent | us-gaap:OtherLiabilitiesCurrent |
| Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] | us-gaap:OtherLiabilitiesNoncurrent | us-gaap:OtherLiabilitiesNoncurrent |
| Operating Lease, Liability, Statement of Financial Position [Extensible List] | us-gaap:OtherLiabilities | us-gaap:OtherLiabilities |