Current and long-term obligations (Details) (USD $)	6 Months Ended		1 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended				6 Months Ended								1 Months Ended	3 Months Ended	6 Months Ended		1 Months Ended	6 Months Ended
	Aug. 03, 2012	Jul. 29, 2011	Aug. 03, 2012 4.125% Senior Notes due 2017	Jul. 12, 2012 4.125% Senior Notes due 2017	Aug. 03, 2012 11.875/12.625% Senior Subordinated Notes due July 15, 2017	Aug. 03, 2012 11.875/12.625% Senior Subordinated Notes due July 15, 2017	Aug. 03, 2012 11.875/12.625% Senior Subordinated Notes due July 15, 2017	Aug. 03, 2012 ABL Facility, as amended and restated	Mar. 15, 2012 ABL Facility, as amended and restated	Feb. 03, 2012 ABL Facility, as amended and restated	Aug. 03, 2012 ABL Facility, as amended and restated LIBOR loans	Aug. 03, 2012 ABL Facility, as amended and restated Base-rate Loans	Aug. 03, 2012 ABL Facility, as amended and restated Letters of credit	Mar. 15, 2012 ABL Facility, as amended and restated Letters of credit	Aug. 03, 2012 Term loan facility	Mar. 30, 2012 Term loan facility	Aug. 03, 2012 Term loan facility Term loan facility, due July 6, 2017	Mar. 30, 2012 Term loan facility Term loan facility, due July 6, 2017	Jul. 29, 2011 10.625% Senior Notes due 2015 Redemption period July 15, 2011	Jul. 29, 2011 10.625% Senior Notes due 2015 Redemption period July 15, 2011	Jul. 29, 2011 10.625% Senior Notes due 2015 Redemption period July 15, 2011	Jul. 15, 2011 10.625% Senior Notes due 2015 Redemption period July 15, 2011	Apr. 29, 2011 10.625% Senior Notes due 2015 Redemption period April 29, 2011	Jul. 29, 2011 10.625% Senior Notes due 2015 Redemption period April 29, 2011
Current and long-term obligations
Facility amount			$ 500,000,000
Maximum financing under credit agreements								1,200,000,000	1,200,000,000				350,000,000	350,000,000
Commitment fees (as a percent)								0.375%
Debt issue cost capitalized				7,100,000					2,700,000									5,200,000
Variable rate basis											LIBOR	Base Rate
Spread on variable rate (as a percent)											1.75%	0.75%
Write off of portion of deferred debt issue cost associated with amendment								1,600,000
Facility amount outstanding								404,900,000		184,700,000					1,964,000,000	1,964,000,000	879,700,000	879,700,000
Principal amount of notes repurchased					450,700,000														839,300,000				25,000,000
Redemption price as percentage of principal amount					105.938%														105.313%				107.00%
Redemption price as percentage of principal amount			101.00%
Loss on debt retirement, net	30,620,000	60,303,000				29,000,000	29,000,000													58,100,000	58,100,000			2,200,000
Stated interest rate (as a percent)				4.125%																		10.625%
Stated interest rate, minimum (as a percent)					11.875%
Stated interest rate, maximum (as a percent)					12.625%
Scheduled debt maturities including capital lease obligations
2014	1,500,000,000
After 2016	$ 1,400,000,000