Retirement-Related Benefits (Schedule of Contribution Expense Related to Defined Contribution Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Contribution expense from retirement plans [Line Items]
Total contribution expense for defined contribution plans	$ 1,480	$ 1,490	$ 1,361
UNITED STATES [Member]
Contribution expense from retirement plans [Line Items]
Total contribution expense for defined contribution plans	1,441	1,290	1,184
Foreign Plan [Member]
Contribution expense from retirement plans [Line Items]
Total contribution expense for defined contribution plans	$ 39	$ 200	$ 177