Leases Supplemental Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 44	$ 51
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Operating Lease, Liability, Current	$ 8	$ 8
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Operating Lease, Liability, Noncurrent	$ 36	$ 43
Operating Lease, Liability	44	51
Finance Lease, Right-of-Use Asset	145	150
Finance Lease, Liability, Current	16	16
Finance Lease, Liability, Noncurrent	129	135
Finance Lease, Liability	$ 145	$ 151