Fair Value Measurements (Notional Amounts and Fair Values of Derivatives) (Details) - USD ($) $ in Millions	Oct. 31, 2022	Jan. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	$ 13,456	$ 15,876
Fair value hedging | Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	8,021	8,021
Cash flow hedges | Cross-currency swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	5,435	7,855
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	(2,632)	(1,095)
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	(869)	(47)
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	$ (1,763)	$ (1,048)