Segments and Disaggregated Revenue - Information For Segments and Corporate and Support (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 30, 2021	Oct. 31, 2020	Aug. 01, 2020	May 02, 2020	Feb. 01, 2020	Nov. 02, 2019	Aug. 03, 2019	May 04, 2019	Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Condensed Consolidated Income Statement Data:
Net sales	$ 6,767.9	$ 6,177.0	$ 6,277.6	$ 6,286.8	$ 6,315.3	$ 5,746.2	$ 5,740.6	$ 5,808.7	$ 25,509.3	$ 23,610.8	$ 22,823.3
Gross profit	2,152.8	1,924.4	1,916.2	1,794.9	1,960.5	1,704.5	1,648.5	1,727.2	7,788.3	7,040.7	6,947.5
Operating income (loss)	681.6	$ 465.5	$ 374.9	$ 365.9	249.4	$ 358.4	$ 268.9	$ 385.5	1,887.9	1,262.2	(939.5)
Interest expense, net									147.3	162.1	370.0
Other expense (income), net									0.8	1.4	(0.5)
Income (loss) before income taxes									1,739.8	1,098.7	(1,309.0)
Depreciation and amortization expense:									686.7	645.7	621.4
Condensed Consolidated Balance Sheet Data:
Goodwill	1,984.4				1,983.3				1,984.4	1,983.3	2,296.6
Total assets	20,696.0				19,574.6				20,696.0	19,574.6
Additions to property, plant and equipment:									898.8	1,034.8	817.1
Corporate, support and Other
Condensed Consolidated Income Statement Data:
Net sales									0.9	0.0	0.0
Gross profit									0.9	0.0	0.0
Operating income (loss)									(365.7)	(333.1)	(284.1)
Depreciation and amortization expense:									31.8	30.1	22.1
Condensed Consolidated Balance Sheet Data:
Total assets	464.5				395.7				464.5	395.7
Additions to property, plant and equipment:									66.3	62.1
Dollar Tree
Condensed Consolidated Income Statement Data:
Net sales									13,265.0	12,507.9	11,712.1
Condensed Consolidated Balance Sheet Data:
Goodwill	424.9				423.8				424.9	423.8	376.5
Dollar Tree | Operating segments
Condensed Consolidated Income Statement Data:
Net sales									13,265.0	12,507.9	11,712.1
Gross profit									4,543.8	4,342.9	4,137.5
Operating income (loss)									1,598.0	1,670.2	1,657.4
Depreciation and amortization expense:									302.3	277.7	254.0
Condensed Consolidated Balance Sheet Data:
Goodwill	424.9				423.8				424.9	423.8
Total assets	8,669.3				7,694.0				8,669.3	7,694.0
Additions to property, plant and equipment:									470.4	547.5
Family Dollar
Condensed Consolidated Income Statement Data:
Net sales									12,243.4	11,102.9	11,111.2
Condensed Consolidated Balance Sheet Data:
Goodwill	1,559.5				1,559.5				1,559.5	1,559.5	1,920.1
Family Dollar | Operating segments
Condensed Consolidated Income Statement Data:
Net sales									12,243.4	11,102.9	11,111.2
Gross profit									3,243.6	2,697.8	2,810.0
Operating income (loss)									655.6	(74.9)	(2,312.8)
Depreciation and amortization expense:									352.6	337.9	$ 345.3
Condensed Consolidated Balance Sheet Data:
Goodwill	1,559.5				1,559.5				1,559.5	1,559.5
Total assets	$ 11,562.2				$ 11,484.9				11,562.2	11,484.9
Additions to property, plant and equipment:									$ 362.1	$ 425.2