Leases Leases - Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating Lease, Cost	$ 18	$ 35
Short-term Lease, Cost	30	49
Variable Lease, Cost	5	6
Lease, Cost	$ 53	$ 90