Leases - Schedule of Maturities of Lease Liabilities (Details) $ in Millions	Dec. 31, 2020 USD ($)
Operating Leases
Remaining three months of 2019	$ 199
2020	160
2021	124
2022	98
2023	79
Thereafter	282
Total lease payments	942
Less: Interest	85
Total lease obligations	857
Finance Leases
Remaining three months of 2019	4
2020	3
2021	3
2022	1
2023	1
Total lease payments	14
Less: Interest	2
Thereafter	2
Finance lease liability	$ 12