Quarterly financial data (unaudited) (Detail) (USD $)	3 Months Ended								12 Months Ended
	Jan. 30, 2015 item	Oct. 31, 2014 item	Aug. 01, 2014 item	May 02, 2014 item	Jan. 31, 2014 item	Nov. 01, 2013 item	Aug. 02, 2013 item	May 03, 2013 item	Jan. 30, 2015 item	Jan. 31, 2014 item	Feb. 01, 2013 item
Selected unaudited quarterly financial data
Number of weeks in a quarter	13	13	13	13	13	13	13	13
Number of quarters in a year									4	4	4
Net sales	$ 4,939,059,000	$ 4,724,409,000	$ 4,724,039,000	$ 4,522,081,000	$ 4,493,945,000	$ 4,381,838,000	$ 4,394,651,000	$ 4,233,733,000	$ 18,909,588,000	$ 17,504,167,000	$ 16,022,128,000
Gross profit	1,565,439,000	1,423,748,000	1,455,574,000	1,357,746,000	1,434,811,000	1,328,493,000	1,377,290,000	1,295,148,000	5,802,507,000	5,435,742,000	5,085,401,000
Operating profit	566,716,000	394,143,000	428,526,000	379,708,000	538,122,000	390,241,000	412,822,000	395,000,000	1,769,093,000	1,736,185,000	1,655,276,000
Net income	355,371,000	236,316,000	251,260,000	222,398,000	322,173,000	237,385,000	245,475,000	220,083,000	1,065,345,000	1,025,116,000	952,662,000
Basic earnings per share (in dollars per share)	$ 1.17	$ 0.78	$ 0.83	$ 0.72	$ 1.01	$ 0.74	$ 0.76	$ 0.67	$ 3.50	$ 3.17	$ 2.87
Diluted earnings per share (in dollars per share)	$ 1.17	$ 0.78	$ 0.83	$ 0.72	$ 1.01	$ 0.74	$ 0.75	$ 0.67	$ 3.49	$ 3.17	$ 2.85
Loss on debt retirement, net										18,871,000	30,620,000
Amount accrued for loss contingency							8,500,000
Loss on agreement to settle a legal matter, net of tax							5,200,000
Effect of agreement to settle a legal matter on earnings per diluted share (in dollars per share)							$ 0.02
Previous Senior Secured Credit Facilities
Selected unaudited quarterly financial data
Loss on debt retirement, net								18,900,000
Loss on debt retirement, net of tax								11,500,000
Effect of pretax loss on debt retirement on earnings per diluted share (in dollars per share)								$ 0.04
Family Dollar
Selected unaudited quarterly financial data
Attempted acquisition, Transaction Costs	6,100,000	8,200,000
Attempted acquisition, related expenses, net of tax	$ 1,300,000	$ 7,400,000
Effect of pre-tax expenses incurred from attempted acquisition activities on earnings per diluted share (in dollars per share)	$ 0.00	$ 0.02