Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Balances - Beginning of Period	$ (587)	$ (562)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,614)
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	18
Balances - End of Period	(2,183)	(562)
Currency Translation And Other [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balances - Beginning of Period	47
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,893)
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	0
Balances - End of Period	(1,846)
Derivative Instruments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balances - Beginning of Period	129
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	168
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	12
Balances - End of Period	309
Minimum Pension Liability [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balances - Beginning of Period	(763)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	111
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	6
Balances - End of Period	$ (646)