Leases - Future Lease Payments for Operating and Finance Leases (Details) $ in Millions	Feb. 29, 2020 USD ($)
Finance lease
2020 (Remaining period)	$ 48
2021	95
2022	92
2023	89
2024	89
2025	87
Later	1,218
Total undiscounted minimum lease payments	1,718
Less: Present value discount	(640)
Lease liability	1,078
Operating lease
2020 (Remaining period)	1,712
2021	3,340
2022	3,176
2023	3,021
2024	2,865
2025	2,690
Later	14,682
Total undiscounted minimum lease payments	31,486
Less: Present value discount	(7,249)
Operating lease liability	$ 24,237