Leases - Maturities of Operating and Finance Lease Liabilities (Details) $ in Millions	Dec. 31, 2019 USD ($)
Finance Leases
2020	$ 84
2021	82
2022	79
2023	77
2024	76
Thereafter	1,056
Total lease payments	1,454
Less: imputed interest	(646)
Total lease liabilities	808
Operating Leases
2020	2,699
2021	2,598
2022	2,444
2023	2,335
2024	2,103
Thereafter	15,654
Total lease payments	27,833
Less: imputed interest	(7,311)
Total lease liabilities	20,522
Total
2020	2,783
2021	2,680
2022	2,523
2023	2,412
2024	2,179
Thereafter	16,710
Total lease payments	29,287
Less: imputed interest	(7,957)
Total lease liabilities	21,330
Future noncancelable subleases, future minimum payments	315
Leases, amount due in excess of remaining estimated economic life	$ 2,200