Lease Obligations - Lessee - Other Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Leases [Abstract]
Operating leases, weighted average remaining lease term	9 years 5 months 26 days		8 years 11 months 1 day
Finance leases, weighted average remaining lease term	14 years 9 months 3 days		14 years 8 months 12 days
Operating leases, weighted average discount rate	2.87%		2.88%
Finance leases, weighted average discount rate	2.69%		2.74%
Cash paid for amounts included in the measurement of lease liabilities:(a)
Operating cash flows from operating leases	$ 22	$ 22
Operating cash flows from finance leases	1	1
Financing cash flows from finance leases	$ 4	$ 3