Basis of presentation and accounting policies (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
Feb. 03, 2012	Jan. 28, 2011	Jan. 29, 2010
Revenue and gain recognition
Liability for outstanding gift cards	$ 2.9	$ 2.4
Advertising costs
Advertising costs	50.4	46.9	41.5
Expenses related to vendor funding for cooperative advertising offset	$ 20.8	$ 14.2	$ 9.0
Income taxes
Percentage of likelihood of realization that the tax position must exceed in order for the amount to be recognized	50.00%

Name:	dg_IncomeTaxAbstract
Namespace Prefix:	dg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The percentage of likelihood of realization that the tax position must exceed in order for the amount to be recognized in the financial statements.

+ References

No definition available.

+ Details

Name:	dg_TaxBenefitsRecognitionBasisForUncertainTaxPositionLikelihoodRealizationGreaterThanPercentage
Namespace Prefix:	dg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of the liability for outstanding gift cards. Retail customers purchase gift cards or gift certificates that can be redeemed at a later date for merchandise or services; those unredeemed represent a liability of the entity because the revenue is being deferred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccruedLiabilitiesForUnredeeemedGiftCards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-7

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 35

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

+ Details

Name:	us-gaap_AdvertisingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total amount received by an entity from a vendor under a cooperative advertising arrangement that has been offset against advertising expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 02-16

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cooperative Advertising

-URI http://asc.fasb.org/extlink&oid=6509061

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 50

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6408645&loc=d3e63872-111659

+ Details

Name:	us-gaap_CooperativeAdvertisingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_MarketingAndAdvertisingExpenseAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RevenueRecognitionAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration