Fair Value Measurements (Notional Amounts And Fair Values Of Interest Rate Swaps) (Details) - USD ($) $ in Millions	Jan. 31, 2022	Jan. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	$ 15,876	$ 9,573
Fair Value Hedging [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	8,021	3,250
Net Investment Hedging [Member] | Cross-currency interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	0	1,250
Cash Flow Hedging [Member] | Cross-currency interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional Amount	7,855	5,073
Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	(1,095)	83
Recurring [Member] | Fair Value Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	(47)	166
Recurring [Member] | Net Investment Hedging [Member] | Cross-currency interest rate swaps [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	311
Recurring [Member] | Cash Flow Hedging [Member] | Cross-currency interest rate swaps [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ (1,048)	$ (394)