Adoption of New Leasing Standard - Lessee - Components of Lease Expense (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended	12 Months Ended
		Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease expense		$ 31	$ 97	$ 147
Short-term lease expense		6	16
Variable lease expense	[1]	12	37
Sublease income		0	(1)
Total Lease expense		$ 49	$ 149

[1] Variable lease expense is related to our leased real estate for offices and warehouses and primarily includes labor and operational costs as well as taxes and insurance.