Inventories - Rollforward of Inventory Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 03, 2018	Jan. 28, 2017	Jan. 30, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 43.2	$ 43.2	$ 28.4
Charged to profit	75.8	57.3	87.6
Utilized	(78.4)	(57.3)	(72.8)
Balance at end of period	$ 40.6	$ 43.2	$ 43.2