Annual report pursuant to Section 13 and 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.7.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
shares in Millions
 9 Months Ended 12 Months Ended
Jul. 06, 2015
USD ($)
shares
Oct. 29, 2016
segment
Jan. 28, 2017
USD ($)
state
distribution_center
province
Jan. 30, 2016
USD ($)
Jan. 31, 2015
USD ($)
Property, Plant and Equipment [Line Items]          
Acquisition cost paid in common stock and equity compensation     $ 0 $ 2,290,100,000 $ 0
Number of retail discount stores     14,300    
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     $ 554,400,000 462,900,000  
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     $ 116,900,000 114,000,000  
Software amortization period (in years)     3 years    
Interest Costs Capitalized     $ 2,400,000 1,300,000 $ 0
Restricted investments     0 82,000,000  
Deferred Compensation Plan Assets     19,800,000 21,100,000  
Asset Impairment Charges     3,700,000 1,600,000 1,500,000
Impairment charge for certain store assets     700,000    
Impairment of Long-Lived Assets to be Disposed of     3,000,000    
Short-term investments     4,000,000 4,000,000  
Advertising costs     60,100,000 32,500,000 18,100,000
Stock-based compensation expense     60,300,000 52,300,000 37,400,000
Payments Related to Tax Withholding for Share-based Compensation     22,200,000 21,600,000 16,000,000
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities     24,700,000 9,700,000 $ 6,600,000
Fair Value, Inputs, Level 1 [Member]          
Property, Plant and Equipment [Line Items]          
Restricted investments     0 82,000,000  
Short-term investments     4,000,000 4,000,000  
Fair Value, Inputs, Level 2 [Member]          
Property, Plant and Equipment [Line Items]          
Diesel fuel swap liabilities     0 800,000  
Secure Senior Notes and Acquisition Notes [Member] | Fair Value, Inputs, Level 1 [Member]          
Property, Plant and Equipment [Line Items]          
Long-term Debt, Fair Value     3,740,300,000 3,754,600,000  
Long term debt - term loans [Member] | Fair Value, Inputs, Level 2 [Member]          
Property, Plant and Equipment [Line Items]          
Long-term Debt, Fair Value     2,828,200,000 3,886,100,000  
Restatement Adjustment [Member] | Accounting Standards Update 2016-09 [Member]          
Property, Plant and Equipment [Line Items]          
Payments Related to Tax Withholding for Share-based Compensation     (21,600,000) (16,000,000)  
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