Restructuring and Impairments - Restructuring Liability (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014 Employee Severance [Member]	Jan. 31, 2013 Employee Severance [Member]	Jan. 31, 2014 Employee Relocation [Member]	Jan. 31, 2013 Employee Relocation [Member]	Jan. 31, 2014 Lease Vacancy [Member] [Domain]	Jan. 31, 2013 Lease Vacancy [Member] [Domain]	Jan. 31, 2014 Other Restructuring [Member]	Jan. 31, 2013 Other Restructuring [Member]	Oct. 31, 2013 Voluntary Separation Program [Member] Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 3	$ 2									$ 11
Restructuring liability at beginning of year	34	89	15	72	0	0	18	17	1	0
Additions	3	3	2	0	1	1	0	1	0	1
Payments	(9)	(30)	(5)	(27)	(1)	(1)	(2)	(2)	(1)	0
Adjustments	0	(1)	(1)	(2)	0	0	0	1	1	0
Restructuring liability at end of year	$ 28	$ 61	$ 11	$ 43	$ 0	$ 0	$ 16	$ 17	$ 1	$ 1