Quarterly report pursuant to Section 13 or 15(d)

PENDING ACQUISITON (Details)

v2.4.1.9
PENDING ACQUISITON (Details) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended 0 Months Ended
May 02, 2015
Jan. 22, 2015
Jan. 31, 2015
May 03, 2014
Business Acquisition [Line Items]        
Other Liabilities, Current $ 474.3us-gaap_OtherLiabilitiesCurrent   $ 385.3us-gaap_OtherLiabilitiesCurrent $ 196.4us-gaap_OtherLiabilitiesCurrent
Family Dollar [Member]        
Business Acquisition [Line Items]        
Business acquisition price per share (usd per share)   59.60us-gaap_BusinessAcquisitionSharePrice
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
   
Expected merger related expenses 35.0dltr_BusinessCombinationEstimatedAcquisitionRelatedCosts
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Business acquisition transaction costs 10.4us-gaap_BusinessCombinationAcquisitionRelatedCosts
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Debt Issuance Cost 45.8us-gaap_DebtIssuanceCosts
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Deferred Finance Costs, Noncurrent, Gross 115.9us-gaap_DeferredFinanceCostsNoncurrentGross
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Expected capitalizable costs related to pending acquisition 174.0dltr_BusinessCombinationCapitalCostEstimate
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Other Liabilities, Current $ 256.3us-gaap_OtherLiabilitiesCurrent
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
     
Family Dollar [Member] | Common Stock [Member] | Minimum [Member]        
Business Acquisition [Line Items]        
Conversion of stock (shares)   0.2484us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
   
Family Dollar [Member] | Common Stock [Member] | Maximum [Member]        
Business Acquisition [Line Items]        
Conversion of stock (shares)   0.3036us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember