Leases - Lease Maturity (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Lease Maturity [Abstract]
2019	$ 61,000,000
2019		$ 62,000,000
2020	106,000,000
2020		54,000,000
2021	62,000,000
2021		35,000,000
2022	35,000,000
2022		12,000,000
2023	5,000,000
2023		5,000,000
Thereafter	1,000,000
Thereafter		49,000,000
Total undiscounted lease payments	270,000,000
Less: amount representing interest	15,000,000
Total operating lease liabilities	255,000,000
Less: current portion of long-term lease liability as of June 30, 2019	104,000,000
Long-term lease liability as of June 30, 2019	$ 151,000,000
Sublease rentals		0
Total minimum lease payments		217,000,000
Future minimum commitments for capital lease obligations		$ 0