Leases - Future Minimum Capital Lease Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Capital Leases
2019	$ 24
2020	19
2021	16
2022	13
2023	8
Years thereafter	16
Total minimum lease payments	96
Interest portion	(23)
Present value of net minimum lease payments	73
Less current portion	18
Noncurrent portion	55
Operating Leases
2019	34
2020	36
2021	34
2022	30
2023	28
Years thereafter	127
Total minimum lease payments	$ 289