Annual report pursuant to Section 13 and 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.8.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
shares in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Jul. 06, 2015
USD ($)
shares
Jul. 29, 2017
USD ($)
Apr. 29, 2017
USD ($)
Oct. 29, 2016
segment
Feb. 03, 2018
USD ($)
state
province
distribution_center
Jan. 28, 2017
USD ($)
Jan. 30, 2016
USD ($)
Property, Plant and Equipment [Line Items]              
Impairment Of Store Assets         $ 3,100,000 $ 700,000  
Acquisition cost paid in common stock and equity compensation         $ 0 0 $ 2,290,100,000
Number of retail discount stores         14,800    
Number of U.S. States, stores operating in | state         48    
Number of Canadian provinces | province         5    
Number of reportable Segments | segment       2      
Money market securities valued at cost, in Cash and cash equivalents         $ 674,100,000 554,400,000  
Debt instruments with original maturities in months, considered cash equivalents, range maximum (in months)             3 months
Settlement of debit card and credit card transaction process business days, range maximum (in business days)             3 months
Warehousing and distribution costs capitalized into inventory         $ 137,400,000 116,900,000  
Software amortization period (in years)         3 years    
Interest Costs Capitalized         $ 2,300,000 2,400,000  
Asset Impairment Charges   $ 2,600,000 $ 50,900,000   18,500,000 0 $ 0
Impairment charge for certain store assets         5,600,000 3,700,000 1,600,000
Impairment of Long-Lived Assets to be Disposed of         2,500,000 3,000,000  
Short-term investments         0 4,000,000  
Advertising costs         106,300,000 60,100,000 32,500,000
Stock-based compensation expense         65,800,000 60,300,000 52,300,000
Payments Related to Tax Withholding for Share-based Compensation         27,400,000 22,200,000 21,600,000
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities         (10,100,000) 24,700,000 $ 9,700,000
Fair Value, Inputs, Level 1 [Member]              
Property, Plant and Equipment [Line Items]              
Short-term investments         0 4,000,000  
Deferred compensation plan assets         20,700,000 19,800,000  
Secure Senior Notes and Acquisition Notes [Member] | Fair Value, Inputs, Level 1 [Member]              
Property, Plant and Equipment [Line Items]              
Long-term debt         3,684,600,000 3,740,300,000  
Long term debt - term loans [Member] | Fair Value, Inputs, Level 2 [Member]              
Property, Plant and Equipment [Line Items]              
Long-term debt         2,187,600,000 2,828,200,000  
Restatement Adjustment [Member] | Accounting Standards Update 2016-09 [Member]              
Property, Plant and Equipment [Line Items]              
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities         $ (21,600,000) $ (16,000,000)  
Buildings [Member] | Minimum [Member]              
Property, Plant and Equipment [Line Items]              
Useful life (in years)         39 years    
Buildings [Member] | Maximum [Member]              
Property, Plant and Equipment [Line Items]              
Useful life (in years)         40 years    
Furniture, fixtures and equipment [Member] | Minimum [Member]              
Property, Plant and Equipment [Line Items]              
Useful life (in years)         3 years    
Furniture, fixtures and equipment [Member] | Maximum [Member]              
Property, Plant and Equipment [Line Items]              
Useful life (in years)         15 years    
Dollar Tree [Member]              
Property, Plant and Equipment [Line Items]              
Price point         $ 1.00    
Family Dollar [Member]              
Property, Plant and Equipment [Line Items]              
Number of distribution centers | distribution_center         11    
UNITED STATES | Dollar Tree [Member]              
Property, Plant and Equipment [Line Items]              
Number of distribution centers | distribution_center         11    
CANADA | Dollar Tree [Member]              
Property, Plant and Equipment [Line Items]              
Number of distribution centers | distribution_center         2    
Family Dollar [Member]              
Property, Plant and Equipment [Line Items]              
Business Combination, Consideration Transferred $ 6,800,000,000            
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares 28.5            
Acquisition cost paid in common stock and equity compensation $ 2,300,000,000