Leases - Lease Maturity (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019
Lease Maturity [Abstract]
2019	$ 80
2020	94
2021	57
2022	34
2023	4
Thereafter	1
Total undiscounted lease payments	270
Less: Amount representing interest	16
Total operating lease liabilities	254	$ 160
Current portion of long-term lease liability as of March 31, 2019	92
Long-term lease liability as of March 31, 2019	$ 162