Taxes (Narrative) (Details) - USD ($) $ in Millions	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Taxes [Line Items]
Deferred tax liability	$ 3,000
Operating loss and capital loss carryforwards	39,300
Valuation allowances	9,542	$ 8,782
Unrecognized tax benefits	3,245	3,135	$ 1,817	$ 1,305
Unrecognized tax benefits that would impact effective tax rate	1,800	$ 1,700
Operating loss and capital loss carryforward expiring by 2040 [Member]
Taxes [Line Items]
Operating loss and capital loss carryforwards	$ 26,600