Share Based Compensation (Details) (USD $)	6 Months Ended
	Jul. 30, 2011
Stock option activity
Outstanding at January 29, 2011,Number of Shares	2,316,648
Outstanding at January 29, 2011,Weighted average Exercise Price	$ 39.51
Exercised, Number of Shares	(776,328)
Exercised, Weighted average Exercise Price	$ 32.22
Forfeited or cancelled, Number of Shares	(19,600)
Forfeited or cancelled, Weighted-Average Exercise Price	$ 42.31
Outstanding at July 30, 2011,Number of Shares	1,520,720
Outstanding at July 30, 2011,Weighted average Exercise Price	$ 43.20
Outstanding at July 30, 2011,Aggregate Intrinsic Value	$ 47,009,327
Outstanding at July 30, 2011,Weighted- Average Remaining Contractual Life	2.8
Stock options exercisable at July 30, 2011, Number of Shares	1,427,670
Stock options exercisable at July 30, 2011, Weighted-Average Exercise Price	$ 42.20
Stock options exercisable at July 30, 2011, Aggregate Intrinsic Value	45,328,427
Stock options exercisable at July 30, 2011, Weighted-Average Remaining Contractual Life	2.5
Stock options expected to become exercisable at July 30, 2011, Number of Shares	88,757
Stock options expected to become exercisable in the future as of July 30, 2011, Weighted Average Exercise Price	$ 58.46
Stock options expected to become exercisable in the future as of July 30, 2011, Aggregate Intrinsic Value	$ 1,602,972
Stock options expected to become exercisable in the future as of July 30, 2011, Weighted Average Remaining Contractual Life	6.9