Lease Obligations - Lessee - Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating leases, weighted average remaining lease term	8 years 11 months 1 day	9 years 21 days
Finance leases, weighted average remaining lease term	14 years 8 months 12 days	12 years 11 months 4 days
Operating leases, weighted average discount rate	2.88%	3.05%
Finance leases, weighted average discount rate	2.74%	2.39%
Cash paid for amounts included in the measurement of lease liabilities:(a)
Operating cash flows from operating leases	$ 88	$ 91	$ 97
Operating cash flows from finance leases	4	3	1
Financing cash flows from finance leases	16	11	5
Gains on sale and leaseback transactions	$ 2	$ 3	$ 5