Leases - Maturities of Lease Liabilities (Details) $ in Millions	Mar. 31, 2019 USD ($)
Operating Leases
2019 (remaining nine months)	$ 26
2020	29
2021	27
2022	23
2023	19
Thereafter	33
Total lease payments	157
Less: interest	(32)
Total	125
Less: current portion	(32)
Long-term portion	93
Financing Leases
2019 (remaining nine months)	7
2020	5
2021	1
2022	1
2023	1
Thereafter	4
Total lease payments	19
Less: interest	(2)
Total	17
Less: current portion	(9)
Long-term portion	$ 8