Leases Assets and Liabilities, Lessee (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Right-of-Use Asset	[1]	$ 103	$ 110
Finance Lease, Right-of-Use Asset	[2]	13	10
Total leased assets		116	120
Operating Lease, Liability, Current		19	20
Finance Lease, Liability, Current		2	4
Operating Lease, Liability, Noncurrent		76	82
Finance Lease, Liability, Noncurrent		6	3
Total leased liabilities		103	109
Favorable leasehold interest		8	9
Finance lease, Accumulated Amortization		$ 3	$ 1

[1] (1)    Operating lease assets include $8 and $9 of favorable leasehold interests as of December 31, 2020 and 2019, respectively.

[2] (2)    Finance lease assets are recorded net of accumulated amortization of $3 and $1 as of December 31, 2020 and 2019, respectively.