Lease Obligations - Lessee - Other Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Leases [Abstract]
Operating leases, weighted average remaining lease term	9 years 9 months 29 days		8 years 11 months 1 day
Finance leases, weighted average remaining lease term	15 years 3 months 18 days		14 years 8 months 12 days
Operating leases, weighted average discount rate	2.93%		2.88%
Finance leases, weighted average discount rate	2.81%		2.74%
Cash paid for amounts included in the measurement of lease liabilities:(a)
Operating cash flows from operating leases	$ 44	$ 44
Operating cash flows from finance leases	2	2
Financing cash flows from finance leases	10	9
Gains on sale-leaseback transactions	$ 4	$ 2