Leases - Summary of Operating and Finance Lease Maturities (Details) $ in Millions	Sep. 30, 2019 USD ($)
Operating
Remaining 2019	$ 48
2020	172
2021	155
2022	136
2023	91
Thereafter	117
Total lease payments	719
Less interest	(60)
Present value of lease liabilities	659
Finance
Remaining 2019	3
2020	10
2021	11
2022	3
2023	0
Thereafter	0
Total lease payments	27
Less interest	(2)
Present value of lease liabilities	$ 25