Quarterly Financial Information (Unaudited) (Details) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Feb. 01, 2020 USD ($) store $ / shares	Nov. 02, 2019 USD ($) store $ / shares	Aug. 03, 2019 USD ($) store $ / shares	May 04, 2019 USD ($) store $ / shares	Feb. 02, 2019 USD ($) store $ / shares	Nov. 03, 2018 USD ($) store $ / shares	Aug. 04, 2018 USD ($) store $ / shares	May 05, 2018 USD ($) store $ / shares	Feb. 01, 2020 USD ($) store $ / shares	Feb. 02, 2019 USD ($) store $ / shares	Feb. 03, 2018 USD ($) $ / shares
Quarterly Financial Information Disclosure [Abstract]
Total net sales	$ 6,315.3	$ 5,746.2	$ 5,740.6	$ 5,808.7	$ 6,205.2	$ 5,538.8	$ 5,525.6	$ 5,553.7	$ 23,610.8	$ 22,823.3	$ 22,245.5
Gross profit	1,960.5	1,704.5	1,648.5	1,727.2	1,912.1	1,671.9	1,663.9	1,699.6	7,040.7	6,947.5	7,021.9
Operating income (loss)	249.4	358.4	268.9	385.5	(2,147.4)	387.8	382.5	437.6	1,262.2	(939.5)	1,999.1
Net income (loss)	$ 123.0	$ 255.8	$ 180.3	$ 267.9	$ (2,307.0)	$ 281.8	$ 273.9	$ 160.5	$ 827.0	$ (1,590.8)	$ 1,714.3
Diluted net income (loss) per share (usd per share) | $ / shares	$ 0.52	$ 1.08	$ 0.76	$ 1.12	$ (9.69)	$ 1.18	$ 1.15	$ 0.67	$ 3.47	$ (6.69)	$ 7.21
Stores open at end of quarter (store) | store	15,288	15,262	15,115	15,264	15,237	15,187	15,073	14,957	15,288	15,237
Comparable store net sales change	0.40%	2.50%	2.40%	2.20%	2.40%	1.00%	1.80%	1.40%
Effect of Fourth Quarter Events [Line Items]
Goodwill impairment									$ 313.0	$ 2,727.0	$ 0.0
Litigation expense	$ 18.0
Litigation expense, effect on diluted earnings per share (in dollars per share) | $ / shares	$ 0.06
Reduction of operating loss carryforwards, effect on net income	$ 24.6
Reduction of operating loss carryforwards, effect on earnings per share (in dollars per share) | $ / shares	$ 0.10
Impairment charge for certain store assets					$ 13.0				9.1	13.0	5.6
Impairment of favorable lease rights					6.1
Impairment of favorable lease rights, effect on net income (loss)					$ 10.0
Impairment of favorable lease rights, effect on net income (loss) (in dollars per share) | $ / shares					$ 0.04
Payment of redemption premiums								$ 114.3		114.3
Amortizable non-cash deferred financing costs								41.2		41.2
Debt transaction costs								0.4
Loss on refinancing of long-term debt								$ 123.6
Loss on refinancing of long-term debt, effect on diluted earning per share (in dollars per share) | $ / shares								$ 0.52
Family Dollar
Effect of Fourth Quarter Events [Line Items]
Goodwill impairment	$ 313.0				$ 2,730.0
Goodwill impairment, net of tax	$ 313.0				$ 2,730.0
Goodwill | Family Dollar
Effect of Fourth Quarter Events [Line Items]
Reduction of diluted net income (loss) (in dollars per share) | $ / shares	$ 1.32				$ 11.46
Family Dollar
Quarterly Financial Information Disclosure [Abstract]
Total net sales									11,102.9	11,111.2	11,081.1
Gross profit									2,697.8	2,810.0	$ 3,023.4
Effect of Fourth Quarter Events [Line Items]
Goodwill impairment	$ 313.0				$ 2,730.0				$ 313.0	$ 2,727.0
Rationalization markdown expense					40.0
Rationalization markdown expense, decrease on net income (loss)					$ 30.8
Rationalization markdown expense, decrease on diluted earnings per share (in dollars per share) | $ / shares					$ 0.13