Leases - Schedule of Maturities of Operating and Finance Leases Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Leases
2019	$ 14		$ 54
2020	45		42
2021	34		34
2022	25		26
2023	20		21
Thereafter	127		117
Total lease payments	265		294
Less imputed interest	(61)
Total operating lease liabilities	204	$ 220
Finance Lease, Liability, Payment, Due [Abstract]
2019	2		5
2020	2		5
2021	2		5
2022	2		4
2023	2		4
Thereafter	5		6
Total lease payments	15		$ 29
Less imputed interest	(2)
Total finance lease liabilities	$ 13