Lease, Cost (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Lease cost		$ 40	$ 79
Variable lease cost	[1]	35	72
Total lease cost		$ 75	$ 151

[1] (a)    Includes short-term leases, which are immaterial.