Short-term Borrowings and Long-term Debt (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2021
Debt Instrument [Line Items]
Short-term borrowings	$ 372	$ 410
Average interest rate	6.60%	2.90%
Letters of credit, drawn	$ 1,800	$ 1,700
Loss on extinguishment of debt	0	2,410	$ 0
Premiums paid to extinguish debt	$ 0	2,317	$ 0
Fronted and Syndicated Lines of Credit \| Minimum
Debt Instrument [Line Items]
Commitment fee	0.00015
Fronted and Syndicated Lines of Credit \| Maximum
Debt Instrument [Line Items]
Commitment fee	0.00040
Fronted and Syndicated Lines of Credit \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate \| Minimum
Debt Instrument [Line Items]
Variable rate commitment	0.0060
Letter of Credit
Debt Instrument [Line Items]
Principal Amount	$ 2,100	$ 1,800

Face (par) amount of debt instrument at time of issuance.

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