Taxes (Schedule of Income Tax Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Current:
U.S. federal	$ 2,991	$ 2,794	$ 2,763
U.S. state and local	742	587	493
International	1,127	1,205	1,495
Total current tax provision	4,860	4,586	4,751
Deferred:
U.S. federal	2,316	663	(361)
U.S. state and local	23	35	(16)
International	(341)	(369)	(93)
Total deferred tax expense (benefit)	1,998	329	(470)
Total provision for income taxes	$ 6,858	$ 4,915	$ 4,281