Subsequent events (Details) (Stock repurchase program, USD $) In Millions, unless otherwise specified	1 Months Ended
Nov. 30, 2011	Dec. 04, 2011 Buck Holdings, L.P.
Subsequent events
Amount of stock repurchase authorized	$ 500
Value of common stock authorized to be repurchased from related parties		$ 185

Represents the value of stock authorized to be repurchased from related parties pursuant to a contractual agreement.

No definition available.

Name:	dg_StockRepurchaseProgramStockToBeRepurchasedRelatedPartiesValue
Namespace Prefix:	dg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant