CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Millions	Total	Common stock and additional paid-in-capital	Accumulated other comprehensive income (loss)	Retained earnings	Total stockholders' equity
Balance at Jan. 31, 2010		$ 1,204.3	$ (3.5)	$ 272.7	$ 1,473.5
Balance (in shares) at Jan. 31, 2010		228.9
Common shares issued under stock award and stock purchase plans, Shares		7.1
Common shares issued under stock award and stock purchase plans, Value		120.9			120.9
Compensation expense related to stock options	80.7				80.7
Tax benefits from employee stock plans		(0.4)			(0.4)
Net income	212.0			212.0	212.0
Other Comprehensive Income (Loss), Net of Tax			2.9		2.9
Stock Repurchased and Retired During Period, Shares	9.0	(9.0)
Stock Repurchased and Retired During Period, Value		(138.3)		(142.0)	(280.3)
Balances at Jan. 31, 2011		1,267.2	(0.6)	342.7	1,609.3
Balance (in shares) at Jan. 31, 2011		227.0
Common shares issued under stock award and stock purchase plans, Shares		8.6
Common shares issued under stock award and stock purchase plans, Value		176.1			176.1
Compensation expense related to stock options	108.8				108.8
Tax benefits from employee stock plans		24.3			24.3
Net income	285.3			285.3	285.3
Other Comprehensive Income (Loss), Net of Tax			6.5		6.5
Stock Repurchased and Retired During Period, Shares		(9.7)
Stock Repurchased and Retired During Period, Value		(211.0)		(116.4)	(327.4)
Balances at Jan. 31, 2012	1,882.9	1,365.4	5.9	511.6	1,882.9
Balance (in shares) at Jan. 31, 2012	225.9	225.9
Common shares issued under stock award and stock purchase plans, Shares		10.2
Common shares issued under stock award and stock purchase plans, Value		220.2			220.2
Compensation expense related to stock options	139.8				139.8
Tax benefits from employee stock plans		(4.3)			(4.3)
Net income	247.4			247.4	247.4
Other Comprehensive Income (Loss), Net of Tax			(11.6)		(11.6)
Stock Repurchased and Retired During Period, Shares		(12.5)
Stock Repurchased and Retired During Period, Value		(271.3)		(159.9)	(431.2)
Balances at Jan. 31, 2013	$ 2,043.2	$ 1,449.8	$ (5.7)	$ 599.1
Balance (in shares) at Jan. 31, 2013	223.6	223.6