Annual report pursuant to Section 13 and 15(d)

PENDING ACQUISITION AND RELATED DEBT Pending Acquisition (Details)

v2.4.1.9
PENDING ACQUISITION AND RELATED DEBT Pending Acquisition (Details) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Jan. 31, 2015
Jul. 27, 2014
Business Acquisition [Line Items]    
Business Combination, Estimated Acquisition Related Costs $ 210.0dltr_BusinessCombinationEstimatedAcquisitionRelatedCosts  
Business Combination, Acquisition Related Costs 75.2us-gaap_BusinessCombinationAcquisitionRelatedCosts  
Business Combination, Acquisition Related Costs Paid 33.5dltr_BusinessCombinationAcquisitionRelatedCostsPaid  
Business Combination Acquisition Related Costs, recorded in Selling, General & Administrative Expense 28.5dltr_BusinessCombinationAcquisitionRelatedCostsrecordedinSellingGeneralAdministrativeExpense  
Business Combination, Acquisition Related Interest Expense Costs 46.7dltr_BusinessCombinationAcquisitionRelatedInterestExpenseCosts  
Business Combination, Estimated Acquisition Related Commitment Fees 22.6dltr_BusinessCombinationEstimatedAcquisitionRelatedCommitmentFees  
Business Combination, Estimated Acquisition Capitalizable Debt Issuance Costs 174.0dltr_BusinessCombinationEstimatedAcquisitionCapitalizableDebtIssuanceCosts  
Business Combination, Contingent Consideration, Asset 70.2us-gaap_BusinessCombinationContingentConsiderationAsset  
Business Combination, Contingent Consideration, Liability $ 112.0us-gaap_BusinessCombinationContingentConsiderationLiability  
Family Dollar [Member]    
Business Acquisition [Line Items]    
Business Acquisition, Share Price   $ 59.60us-gaap_BusinessAcquisitionSharePrice
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
Maximum [Member] | Family Dollar [Member] | Common Stock [Member]    
Business Acquisition [Line Items]    
Conversion of Stock, Shares Converted 0.3036us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
 
Minimum [Member] | Family Dollar [Member] | Common Stock [Member]    
Business Acquisition [Line Items]    
Conversion of Stock, Shares Converted 0.2484us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_BusinessAcquisitionAxis
= dltr_FamilyDollarMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember