Basis of presentation and accounting policies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Feb. 03, 2012 week M States Stores	Jan. 28, 2011 week	Jan. 29, 2010 week
Basis of presentation and accounting policies
Fiscal year, number of weeks	53	52	52
Business description
Number of stores through which entity sells general merchandise on a retail basis	9,937
Number of states which entity covers	38
Cash and cash equivalents
Maximum original maturity period at time of purchase of liquid investments classified as cash equivalents (in months)	3
Payments due from processors for electronic tender transactions classified as cash and cash equivalents	$ 38.7	$ 26.1
Amount of outstanding but un-presented checks	148.3	153.6
Minimum threshold of cash balances to be maintained as set by insurance regulators	20
Merchandise inventories
Excess of current cost over LIFO cost	100.5	52.8
LIFO provision (benefit)	$ 47.7	$ 5.3	$ (2.5)