Employee Stock and Savings Plans Summary of Weighted Average Grant Date Fair Values (Details) (USD $)	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Weighted average grant date fair value of nonvested restricted stock units granted in period	$ 16.74
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Weighted average grant date fair value of options granted	$ 7.18	$ 5.43	$ 5.02
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Weighted average grant date fair value of nonvested restricted stock units granted in period	$ 16.74	$ 10.91	$ 9.61
Employee Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Weighted average grant date fair value of nonvested restricted stock units granted in period	$ 3.82	$ 3.19	$ 2.17