Lease Obligations - Lessee - Other Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Leases [Abstract]
Operating leases, weighted average remaining lease term	10 years 10 months 24 days		10 years 9 months 18 days
Finance leases, weighted average remaining lease term	15 years 3 months 10 days		15 years 3 months 21 days
Operating leases, weighted average discount rate	3.54%		3.35%
Finance leases, weighted average discount rate	3.02%		2.94%
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 46	$ 44
Operating cash flows from finance leases	2	2
Financing cash flows from finance leases	8	10
Gains on sale-leaseback transactions	$ 1	$ 4