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Shareholders' Equity (Details 2) (USD $)
 3 Months Ended 11 Months Ended 12 Months Ended
Jan. 31, 2015
Nov. 01, 2014
Aug. 02, 2014
May 03, 2014
Feb. 01, 2014
Nov. 02, 2013
Aug. 03, 2013
May 04, 2013
Feb. 02, 2013
Jan. 31, 2015
Feb. 01, 2014
Mar. 03, 2012
Jan. 28, 2012
Jun. 30, 2011
Jun. 30, 2007
Outstanding Options to Purchase Common Stock [Line Items]                              
Net cash proceeds from the exercise of stock options (in dollars)                 $ 1,000,000us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions $ 42,000,000us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions $ 158,000,000us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions        
Weighted-average grant-date fair value of stock options granted (in dollars per share)                 $ 5.11us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 9.09us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 7.77us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue        
Exercisable stock options (in shares) 13,995,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber                 13,995,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber          
Percentage of exercisable stock options (as a percent) 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage                 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage          
Exercisable stock options, weighted-average price (in dollars per share) $ 39.37us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice                 $ 39.37us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice          
Unexercisable stock options (in shares) 3,300,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber                 3,300,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber          
Percentage of unexercisable stock options (as a percent) 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage                 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage          
Unexercisable stock options, weighted-average price (in dollars per share) $ 26.11bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice                 $ 26.11bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice          
Total outstanding stock options (in shares) 17,342,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber       22,101,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber         17,342,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 22,101,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber        
Percentage of outstanding stock options (as a percent) 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage                 100.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage          
Outstanding stock options, weighted-average price (in dollars per share) $ 36.81us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice       $ 36.38us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice         $ 36.81us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 36.38us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice        
Numerator [Abstract]                              
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest 524,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 116,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 137,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 469,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 300,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 50,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 233,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 112,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest (259,000,000)us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 1,246,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest 695,000,000us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest        
Net earnings from continuing operations attributable to Best Buy Co., Inc., diluted                 (259,000,000)us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted [1] 1,246,000,000us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted 695,000,000us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted        
Denominator [Abstract]                              
Weighted-average common shares outstanding (in shares)                 338,600,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic [1] 349,500,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 342,100,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic        
Effect of Potentially Dilutive Securities [Abstract]                              
Stock options and other (in shares)                 0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements [1] 4,100,000us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements 5,500,000us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements        
Weighted-average common shares outstanding, assuming dilution (in shares)                 338,600,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding [1] 353,600,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 347,600,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding        
Earnings per share attributable to Best Buy Co., Inc.                              
Basic (in dollars per share)                 $ (0.76)us-gaap_IncomeLossFromContinuingOperationsPerBasicShare [1] $ 3.57us-gaap_IncomeLossFromContinuingOperationsPerBasicShare $ 2.03us-gaap_IncomeLossFromContinuingOperationsPerBasicShare        
Diluted (in dollars per share) $ 1.47us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.33us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.39us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 1.33us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.85us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.15us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.67us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.33us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ (0.76)us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare [1] $ 3.53us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 2.00us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare        
Share repurchases authorized (in shares)                           5,000,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1 5,500,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]                              
Foreign currency translation 382,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax       485,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax       113,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax 382,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax 485,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax 93,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax 104,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax    
Unrealized gains (losses) on available-for-sale investments 0us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax       7,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax       (1,000,000)us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax 0us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax 7,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax (3,000,000)us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax (3,000,000)us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax    
Total 382,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax       492,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax       112,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 382,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 492,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 90,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax 101,000,000us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value                 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue 13,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue 39,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue        
Actual income tax benefit realized from stock option exercises (in dollars)                 0us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions 5,000,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions 13,000,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions        
In-the-money [Member]                              
Outstanding Options to Purchase Common Stock [Line Items]                              
Exercisable stock options (in shares) 2,800,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 2,800,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Percentage of exercisable stock options (as a percent) 20.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 20.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Exercisable stock options, weighted-average price (in dollars per share) $ 22.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 $ 22.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Unexercisable stock options (in shares) 3,100,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 3,100,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Percentage of unexercisable stock options (as a percent) 94.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 94.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Unexercisable stock options, weighted-average price (in dollars per share) $ 25.60bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 $ 25.60bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Total outstanding stock options (in shares) 5,900,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 5,900,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Percentage of outstanding stock options (as a percent) 34.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 34.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Outstanding stock options, weighted-average price (in dollars per share) $ 24.38us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		                 $ 24.38us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_InMoneyStockOptionsMember		          
Out-of-the-money [Member]                              
Outstanding Options to Purchase Common Stock [Line Items]                              
Exercisable stock options (in shares) 11,200,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 11,200,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Percentage of exercisable stock options (as a percent) 80.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 80.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Exercisable stock options, weighted-average price (in dollars per share) $ 43.42us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 $ 43.42us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Unexercisable stock options (in shares) 200,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 200,000.0bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Percentage of unexercisable stock options (as a percent) 6.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 6.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisablePercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Unexercisable stock options, weighted-average price (in dollars per share) $ 34.25bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 $ 34.25bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnexercisableWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Total outstanding stock options (in shares) 11,400,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 11,400,000.0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Percentage of outstanding stock options (as a percent) 66.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 66.00%bby_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPercentage
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
Outstanding stock options, weighted-average price (in dollars per share) $ 43.27us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		                 $ 43.27us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= bby_OutOfMoneyStockOptionsMember		          
June 2011 share repurchase program [Member}                              
Outstanding Options to Purchase Common Stock [Line Items]                              
Amounting remaining for additional share repurchases 4,000,000,000us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		                 4,000,000,000us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		          
Open Market Repurchases [Abstract]                              
Total number of shares repurchased                 6,300,000us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		 0us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		 0us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		        
Total cost of shares repurchased                 122,000,000us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		 0us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		 0us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
/ us-gaap_ShareRepurchaseProgramAxis
= bby_June2011ShareRepurchaseProgramMember		        
Market-based [Member]                              
Outstanding Options to Purchase Common Stock [Line Items]                              
Unrecognized compensation (in dollars) $ 20,000,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= bby_MarketBasedShareAwardsMember		                 $ 20,000,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= bby_MarketBasedShareAwardsMember		          
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]                              
Weighted-average period over which compensation expense is expected to be recognized (in years)                   1 year 11 months          
Employee Stock [Member]                              
Outstanding Options to Purchase Common Stock [Line Items]                              
Issuance of common stock under employee stock purchase plan (in shares)                 1,000,000us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockMember		 300,000us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockMember		 600,000us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockMember		        
[1] The calculation of diluted loss per share for fiscal 2013 (11-month) does not include potentially dilutive securities because their inclusion would be anti-dilutive (i.e., reduce the net loss per share).