Leases - Maturities of Operating and Finance Lease Liabilities (Details) $ in Millions	Jun. 30, 2019 USD ($)
Financing Leases
2019 (remaining six months)	$ 34
2020	68
2021	65
2022	61
2023	59
Thereafter	825
Total financing lease payments	1,112
Less: imputed interest	(527)
Total lease liabilities	585
Operating Leases
2019 (remaining six months)	1,356
2020	2,645
2021	2,516
2022	2,356
2023	2,244
Thereafter	16,857
Total operating lease payments	27,974
Less: imputed interest	(7,332)
Total lease liabilities	20,642
Total
2019 (remaining six months)	1,390
2020	2,713
2021	2,581
2022	2,417
2023	2,303
Thereafter	17,682
Total lease payments	29,086
Less: imputed interest	(7,859)
Less: imputed interest	21,227
Future noncancelable subleases, future minimum payments	327
Leases, amount due in excess of remaining estimated economic life	$ 2,200