Leases - Lease Maturities (Details) $ in Millions	Jun. 30, 2019 USD ($)
Finance Leases
July 1, 2019 - December 31, 2019	$ 3
2020	10
2021	6
2022	2
2023	50
Thereafter	4
Total lease payments	75
Less: imputed interest	(12)
Total	63
Operating Leases
July 1, 2019 - December 31, 2019	7
2020	14
2021	13
2022	10
2023	8
Thereafter	56
Total lease payments	108
Less: imputed interest	(28)
Total	$ 80