Short-Term Borrowings And Long-Term Debt (Information On Significant Long-Term Debt Issued) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2013
Debt Instrument [Line Items]
Principal Amount	$ 5,000
April 15, 2014 [Member]
Debt Instrument [Line Items]
Issue Date	Apr. 18, 2011
Debt Instrument, Maturity Date	Apr. 15, 2014
Interest Rate	1.625%
Principal Amount	1,000
April 15, 2016 [Member]
Debt Instrument [Line Items]
Issue Date	Apr. 18, 2011
Debt Instrument, Maturity Date	Apr. 15, 2016
Interest Rate	2.80%
Principal Amount	1,000
April 15, 2021 [Member]
Debt Instrument [Line Items]
Issue Date	Apr. 18, 2011
Debt Instrument, Maturity Date	Apr. 15, 2021
Interest Rate	4.25%
Principal Amount	1,000
April 15, 2041 [Member]
Debt Instrument [Line Items]
Issue Date	Apr. 18, 2011
Debt Instrument, Maturity Date	Apr. 15, 2041
Interest Rate	5.625%
Principal Amount	$ 2,000