Leases Other Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Short-term Lease, Cost	$ 1
Variable Lease, Cost	6
Operating cash flows from finance leases	0
Operating cash flows from operating leases	2
Financing cash flows from finance leases	0
Right-of-use assets obtained in exchange for new operating lease liabilities	6
Right-of-use assets obtained in exchange for new financing lease liabilities	$ 1