Leases Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		$ 15
2020		20
2021		13
2022		26
2023		9
2024 and thereafter		1
Total minimum payments		84
Less: Amount representing interest		18
Present value of minimum payments		66
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remaining six months of 2019	$ 16
2020	25
2021	20
2022	14
2023	11
2024 and thereafter	78
Total lease payments	164
Less: Amount representing interest	69
Operating Lease, Liability	95
Operating Leases [Abstract]
2019		33
2020		24
2021		20
2022		13
2023		10
2024 and thereafter		61
Total minimum payments		$ 161
Finance Lease, Liability, Payment, Due [Abstract]
Remaining six months of 2019	2
2020	8
2021	1
2022	0
2023	0
2024 and thereafter	1
Total lease payments	12
Less: Amount representing interest	1
Finance Lease, Liability	$ 11