Taxes (Schedule of Deferred Tax Balances) (Details) - USD ($) $ in Millions	Jan. 31, 2022	Jan. 31, 2021
Deferred tax assets:
Loss and tax credit carryforwards	$ 9,456	$ 9,179
Accrued liabilities	2,752	2,582
Share-based compensation	231	224
Lease obligations	4,320	4,450
Other	893	589
Total deferred tax assets	17,652	17,024
Valuation allowances	(9,542)	(8,782)
Deferred tax assets, net of valuation allowances	8,110	8,242
Deferred tax liabilities:
Property and equipment	4,414	4,802
Acquired intangibles	1,065	1,071
Inventory	1,588	1,235
Lease right of use assets	4,355	4,390
Mark-to-market investments	1,825	2,678
Other	307	675
Total deferred tax liabilities	13,554	14,851
Net deferred tax liabilities	$ 5,444	$ 6,609