Commitments and Contingencies (Details) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended		24 Months Ended
	Jul. 31, 2016 USD ($) derivativeactions	May 01, 2016 USD ($)	Jul. 31, 2016 USD ($) derivativeactions	Jan. 31, 2016 USD ($) derivativeactions	Feb. 01, 2015 USD ($)	Jul. 31, 2016 USD ($) derivativeactions
Insurance [Abstract]
Network Security Insurance Coverage			$ 100.0	$ 100.0	$ 100.0
Network Security Insurance Deductible			10.0	10.0	$ 7.5
Data Breach [Member]
Loss Contingency Accrual [Roll Forward]
Data Breach, Accrued Liabilities, Beginning Balance	$ (27.0)	$ (34.0)	(34.0)
Data Breach, Accrued Liabilities, Expenses Incurred	(2.0)	(2.0)	(4.0)			$ (265.0)
Data Breach, Accrued Liabilities, Payments Made		9.0
Data Breach, Accrued Liabilities, Ending Balance	(29.0)	(27.0)	(29.0)	(34.0)		(29.0)
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]
Data Breach, Insurance Receivable, Beginning Balance	55.0	70.0	70.0
Data Breach, Insurance Receivable, Insurance Receivable Recorded	0.0					100.0
Data Breach, Insurance Receivable, Payments Received	(10.0)	(15.0)				(55.0)
Data Breach, Insurance Receivable, Ending Balance	$ 45.0	55.0	$ 45.0	$ 70.0		$ 45.0
Loss Contingency, Information about Litigation Matters [Abstract]
Data Breach, Number of Actions Filed	57		57			57
Number Of Purported Shareholder Derivative Actions Filed | derivativeactions	1		1	2		1
Data Breach, Expenses Incurred Net of Insurance Receivable Recorded						$ 165.0
Data Breach, Insurance Receivable, Payments Received	$ 10.0	$ 15.0				$ 55.0