Leases - Summary of Operating and Finance Lease Maturities (Details) $ in Millions	Jun. 30, 2019 USD ($)
Operating
Remaining 2019	$ 101
2020	165
2021	151
2022	132
2023	88
Thereafter	119
Total lease payments	756
Less interest	(67)
Present value of lease liabilities	689
Finance Lease Liabilities, Payments, Due [Abstract]
Remaining 2019	5
2020	11
2021	11
2022	3
2023	0
Thereafter	0
Total lease payments	30
Less interest	(2)
Present value of lease liabilities	$ 28