Short-term Borrowings and Long-term Debt (Schedule of Long-term Debt Instruments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Long-term debt due within one year
Balances as of February 1, 2020	$ 5,362
Repayments of long-term debt	(2,937)
Reclassifications of long-term debt	3,125
Other	3
Balances as of July 31, 2020	5,553	$ 4,396
Long-term debt
Balances as of February 1, 2020	43,714
Repayments of long-term debt	0
Reclassifications of long-term debt	(3,125)
Other	370
Balances as of July 31, 2020	40,959	44,404
Total
Balances as of February 1, 2020	49,076
Proceeds from issuance of long-term debt	0	$ 4,020
Repayments of long-term debt	(2,937)
Reclassifications of long-term debt	0
Other	373
Balances as of July 31, 2020	$ 46,512