Derivative Financial Instruments (Balance Sheet Classification Of Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2013	Jan. 31, 2013
Fair Value Hedging [Member]
Derivative [Line Items]
Derivative Assets	$ 11	$ 60
Derivative Liabilities	0
Fair Value Hedging [Member] | PrepaidExpensesandandOther [Member]
Derivative [Line Items]
Derivative Assets	11	29
Fair Value Hedging [Member] | OtherAssetsandDeferredCharges [Member]
Derivative [Line Items]
Derivative Assets		31
Net Investment Hedging [Member]
Derivative [Line Items]
Derivative Assets	139	223
Nonderivative Hedging Instruments	6,040	6,963
Net Investment Hedging [Member] | OtherAssetsandDeferredCharges [Member]
Derivative [Line Items]
Derivative Assets	139	223
Net Investment Hedging [Member] | LongTermDebtDueWithinOneYear(HedgedItem) [Member]
Derivative [Line Items]
Nonderivative Hedging Instruments	1,015	818
Net Investment Hedging [Member] | Long-term Debt [Member]
Derivative [Line Items]
Nonderivative Hedging Instruments	5,025	6,145
Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative Assets	577	327
Derivative Liabilities	2	95
Cash Flow Hedging [Member] | OtherAssetsandDeferredCharges [Member]
Derivative [Line Items]
Derivative Assets	577	327
Cash Flow Hedging [Member] | Accrued Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities	1	4
Cash Flow Hedging [Member] | DeferredIncomeTaxesandOther [Member]
Derivative [Line Items]
Derivative Liabilities	$ 1	$ 91