Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019	Feb. 18, 2021	Feb. 01, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par (in USD per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	11,000	11,000
Sale of subsidiary stock	$ 3,239	$ 140	$ 52
Share-based compensation expense	1,163	1,169	854
Tax benefit	$ 300	$ 300	200
Compensation awards (in shares)						260
2021 Share Repurchase Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase program					$ 20,000
Flipkart [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate ownership, percent		83.00%
Sale of Stock, Percentage of Ownership after Transaction	75.00%
Sale of Stock, Percentage of Ownership after Transaction	75.00%
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, issued (in shares)	2,800	2,800
Shares, outstanding (in shares)	2,800	2,800
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 659	$ 742	$ 553
Expected dividend rate	3.80%	4.40%	4.90%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend rate	4.20%	4.50%	5.10%
Restricted Stock And Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 321	$ 277	$ 270
Annual [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			25.00%
Vesting period			4 years
Three Years from Grant Date [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage				50.00%
Five Years from Grant Date [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage				50.00%
[Minimum] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
[Minimum] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	0.00%
[Minimum] | Restricted Stock And Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
[Maximum] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				5 years
[Maximum] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	150.00%
[Maximum] | Restricted Stock And Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years