Fair Value Measurements (Notional Amounts and Fair Values of Derivatives) (Details) - USD ($) $ in Millions	Apr. 30, 2025	Jan. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	$ 10,674	$ 10,223
Fair value hedging \| Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	4,771	4,771
Cash flow hedges \| Cross-currency swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	5,903	5,452
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	(1,488)	(1,999)
Recurring \| Fair value hedging \| Interest rate swap \| Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	(458)	(611)
Recurring \| Cash flow hedges \| Cross-currency swaps \| Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ (1,030)	$ (1,388)

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Nominal or face amount used to calculate payment on derivative.

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