Annual report pursuant to Section 13 and 15(d)

DERIVATIVE FINANCIAL INSTRUMENTS (Details)

v2.4.1.9
DERIVATIVE FINANCIAL INSTRUMENTS (Details) (USD $)
In Millions, unless otherwise specified
Jan. 31, 2015
gal
Feb. 01, 2014
gal
Feb. 02, 2013
gal
Derivative [Line Items]      
Derivative Financial Instruments Liabilitiies Fair Value Diesel Fuel Swap Disclosure 5.7dltr_DerivativeFinancialInstrumentsLiabilitiiesFairValueDieselFuelSwapDisclosure    
Fuel Derivative Contracts [Member]      
Derivative [Line Items]      
Nonmonetary notional amount 1,600,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember 		2,800,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember 		4,800,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember
Diesel fuel need in derivative contracts (in hundredths) 10.00%us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember 		20.00%us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember 		35.00%us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
/ us-gaap_DerivativeByNatureAxis
= us-gaap_CommodityContractMember
Commodity Contract 2 [Member]      
Derivative [Line Items]      
Nonmonetary notional amount 6,600,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeByNatureAxis
= dltr_CommodityContract2Member 		   
Diesel fuel need in derivative contracts (in hundredths) 40.00%us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
/ us-gaap_DerivativeByNatureAxis
= dltr_CommodityContract2Member