Benefit plans (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 01, 2019	Feb. 02, 2018	Feb. 03, 2017
Benefit plans
Matching contribution expense related to the Company's 401(k) plan	$ 20.2	$ 17.5	$ 16.0
Compensation expense for the Dollar General Corporation CDP/SERP Plan	$ 0.7	$ 0.7	$ 0.7