Leases - Future Maturities of Lease Liabilities (Details) $ in Millions	Sep. 30, 2019 USD ($)
Operating Leases
2019 (excluding the nine months ended September 30, 2019)	$ 11
2020	45
2021	39
2022	31
2023	21
Thereafter	114
Total lease payments	261
Less: imputed interest	(55)
Total	206
Finance Leases
2019 (excluding the nine months ended September 30, 2019)	6
2020	3
2021	3
2022	3
2023	4
Thereafter	23
Total lease payments	42
Less: imputed interest	(7)
Total	$ 35