Quarterly financial data (unaudited) (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 29, 2021 USD ($) item $ / shares	Oct. 30, 2020 USD ($) item $ / shares	Jul. 31, 2020 USD ($) item $ / shares	May 01, 2020 USD ($) item $ / shares	Jan. 31, 2020 USD ($) item $ / shares	Nov. 01, 2019 USD ($) item $ / shares	Aug. 02, 2019 USD ($) item $ / shares	May 03, 2019 USD ($) item $ / shares	Jan. 29, 2021 USD ($) $ / shares	Jan. 31, 2020 USD ($) $ / shares	Feb. 01, 2019 USD ($) $ / shares
Selected unaudited quarterly financial data
Number of weeks in a quarter | item	13	13	13	13	13	13	13	13
Net sales	$ 8,414,524	$ 8,199,625	$ 8,684,241	$ 8,448,449	$ 7,157,642	$ 6,991,393	$ 6,981,753	$ 6,623,185	$ 33,746,839	$ 27,753,973	$ 25,625,043
Gross profit	2,736,695	2,568,240	2,818,235	2,595,692	2,272,763	2,065,086	2,148,936	2,002,276	10,718,862	8,489,061	7,803,870
Operating profit	872,224	773,130	1,042,627	866,784	720,875	491,417	577,775	512,237	3,554,765	2,302,304	2,116,306
Net income	$ 642,743	$ 574,260	$ 787,601	$ 650,446	$ 535,437	$ 365,550	$ 426,555	$ 385,013	$ 2,655,050	$ 1,712,555	$ 1,589,472
Basic earnings per share (in dollars per share) | $ / shares	$ 2.64	$ 2.32	$ 3.15	$ 2.58	$ 2.11	$ 1.43	$ 1.65	$ 1.49	$ 10.70	$ 6.68	$ 5.99
Diluted earnings per share (in dollars per share) | $ / shares	$ 2.62	$ 2.31	$ 3.12	$ 2.56	$ 2.10	$ 1.42	$ 1.65	$ 1.48	$ 10.62	$ 6.64	$ 5.97
Legal fees							$ 31,000
Leagl fees, net of tax							$ 24,100
Effect of legal expenses on earnings per diluted share (in dollars per share) | $ / shares							$ (0.09)