Lease Obligations - Lessee - Other Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Lease obligations other information [Line Items]
Finance lease weighted average discount rate, percent	4.30%
Operating lease weighted average discount rate, percent	3.19%
Operating lease weighted average remaining lease term	9 years 5 months 23 days
Finance lease weighted average remaining lease term	14 years 2 months 1 day
Lease liability
Lease obligations other information [Line Items]
Gains on sale and leaseback transactions, net	$ 5
Operating cash flows from operating leases	97
Operating cash flows from finance leases	1
Financing cash flows from finance leases	$ 5