Leases - Schedule of Future Minimum Operating and Finance Lease Payments (Details) $ in Millions	Mar. 31, 2019 USD ($)
Operating Leases
2019 (excluding the three months ended March 31, 2019)	$ 13
2020	15
2021	12
2022	10
2023	8
Thereafter	24
Total lease payments	82
Less imputed interest	13
Total lease liabilities	69
Finance Leases
2019 (excluding the three months ended March 31, 2019)	2
2020	3
2021	14
2022	3
2023	3
Thereafter	38
Total lease payments	63
Less imputed interest	18
Total lease liabilities	$ 45