Dollar Tree, Inc. Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans (Details) $ in Millions	12 Months Ended
Employee Benefit Plans (Details) $ in Millions	Jan. 29, 2022 USD ($) year hour	Jan. 30, 2021 USD ($)	Feb. 01, 2020 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Age over which all employees have 401K benefits available \| year	21
Employee service years required for available 401K benefits (in years)	1 year
Minimum hours in a 401K qualifying one year period (in hours) \| hour	1,000
Plan expenses	$ 28.8	$ 26.4	$ 25.1
Cost of sales
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan expenses	8.2	7.4	8.1
Selling, general and administrative expenses
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan expenses	$ 20.6	$ 19.0	$ 17.0