Lease Obligations - Lessee - Other Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Other Information
Finance Lease Weighted Average Discount Rate, Percent	4.78%
Operating Lease Weighted Average Discount Rate, Percent	3.24%
Operating Lease Weighted Average Remaining Lease Term	9 years 4 months 6 days
Finance Lease Weighted Average Remaining Lease Term	11 years 4 months 6 days
Gains and losses on sale and leaseback transations, net	$ 5
Lease liability
Other Information
Operating Cash Flows from Operating Leases	72
Operating Cash Flows from Finance Leases	1
Financing Cash Flows from Finance Leases	$ 3