Shareholders' Equity (Details 2) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	May 02, 2015	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015	Feb. 01, 2014	Jun. 30, 2011
Outstanding Options to Purchase Common Stock [Line Items]
Net cash proceeds from the exercise of stock options (in dollars)									$ 164	$ 40	$ 42
Weighted-average grant-date fair value of stock options granted (in dollars per share)									$ 8.04	$ 11.59	$ 9.09
Exercisable stock options (in shares)	5,900,000								5,900,000
Percentage of exercisable stock options (as a percent)	100.00%								100.00%
Exercisable stock options, weighted-average price (in dollars per share)	$ 36.64								$ 36.64
Unexercisable stock options (in shares)	1,100,000.0								1,100,000.0
Percentage of unexercisable stock options (as a percent)	100.00%								100.00%
Unexercisable stock options, weighted-average price (in dollars per share)	$ 36.54								$ 36.54
Total outstanding stock options (in shares)	6,987,000				14,242,000				6,987,000	14,242,000
Percentage of outstanding stock options (as a percent)	100.00%								100.00%
Outstanding stock options, weighted-average price (in dollars per share)	$ 36.61				$ 36.51				$ 36.61	$ 36.51
Adjustment for assumed dilution:
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ 607	$ 192	$ 182	$ 226	$ 477	$ 129	$ 164	$ 37	$ 1,207	$ 807	$ 1,246
Denominator [Abstract]
Weighted-average common shares outstanding (in shares)									318,500,000	346,500,000	349,500,000
Effect of Potentially Dilutive Securities [Abstract]
Stock options and other (in shares)									4,100,000	4,200,000	4,100,000
Weighted-average common shares outstanding, assuming dilution (in shares)									322,600,000	350,700,000	353,600,000
Earnings per share attributable to Best Buy Co., Inc.
Basic (in dollars per share)									$ 3.79	$ 2.33	$ 3.57
Diluted (in dollars per share)	$ 1.91	$ 0.60	$ 0.56	$ 0.69	$ 1.39	$ 0.37	$ 0.46	$ 0.10	$ 3.74	$ 2.30	$ 3.53
Share repurchases authorized (in shares)													$ 5,000
Open Market Repurchases [Abstract]
Stock Repurchased and Retired at ASR Settlement, Shares									1,600,000
Stock Repurchased and Retired During Period, Value									$ 45	$ 120
Payments for Repurchase of Common Stock									698	1,000	$ 0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation	$ 279				$ 271				279	271	382	$ 485
Unrealized gains (losses) on available-for-sale investments	0				0				0	0	0	7
Total	$ 279				$ 271				279	271	382	$ 492
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value									55	14	13
Actual income tax benefit realized from stock option exercises (in dollars)									$ 19	$ 5	$ 5
In-the-money [Member]
Outstanding Options to Purchase Common Stock [Line Items]
Exercisable stock options (in shares)	2,300,000.0								2,300,000.0
Percentage of exercisable stock options (as a percent)	39.00%								39.00%
Exercisable stock options, weighted-average price (in dollars per share)	$ 26.38								$ 26.38
Unexercisable stock options (in shares)	500,000.0								500,000.0
Percentage of unexercisable stock options (as a percent)	45.00%								45.00%
Unexercisable stock options, weighted-average price (in dollars per share)	$ 30.84								$ 30.84
Total outstanding stock options (in shares)	2,800,000.0								2,800,000.0
Percentage of outstanding stock options (as a percent)	40.00%								40.00%
Outstanding stock options, weighted-average price (in dollars per share)	$ 27.13								$ 27.13
Out-of-the-money [Member]
Outstanding Options to Purchase Common Stock [Line Items]
Exercisable stock options (in shares)	3,600,000.0								3,600,000.0
Percentage of exercisable stock options (as a percent)	61.00%								61.00%
Exercisable stock options, weighted-average price (in dollars per share)	$ 43.45								$ 43.45
Unexercisable stock options (in shares)	600,000.0								600,000.0
Percentage of unexercisable stock options (as a percent)	55.00%								55.00%
Unexercisable stock options, weighted-average price (in dollars per share)	$ 40.66								$ 40.66
Total outstanding stock options (in shares)	4,200,000.0								4,200,000.0
Percentage of outstanding stock options (as a percent)	60.00%								60.00%
Outstanding stock options, weighted-average price (in dollars per share)	$ 43.01								$ 43.01
Time-Based Share Awards [Member]
Outstanding Options to Purchase Common Stock [Line Items]
Share-based Payment Award, Award Vesting Period, Maximum									4 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights									25% of the award vests on the date of grant and 25% vests on each of the three anniversary dates thereafter
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period									2,979,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value									$ 32.76
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period									2,202,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value									$ 30.83
Unrecognized compensation (in dollars)	$ 98								$ 98
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 8 months
Market-based [Member]
Outstanding Options to Purchase Common Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value									$ 33.27
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period									781,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value									$ 26.84
Unrecognized compensation (in dollars)	23								$ 23
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 8 months
Employee Stock [Member]
Outstanding Options to Purchase Common Stock [Line Items]
Issuance of common stock under employee stock purchase plan (in shares)									200,000	200,000	300,000
Open market [Domain]
Open Market Repurchases [Abstract]
Average share price										$ 31.03
June 2011 share repurchase program [Member}
Outstanding Options to Purchase Common Stock [Line Items]
Amounting remaining for additional share repurchases	$ 2,200								$ 2,200
Open Market Repurchases [Abstract]
Total number of shares repurchased									21,100,000	32,800,000
Payments for Repurchase of Common Stock									$ 751	$ 1,000
Average share price									$ 35.54	$ 30.53
June 2011 share repurchase program [Member} | Open market [Domain]
Open Market Repurchases [Abstract]
Stock Repurchased and Retired During Period, Value									$ 706	$ 880
Average share price									$ 36.11
January 2016 ASR [Domain]
Open Market Repurchases [Abstract]
Stock Repurchased and Retired at ASR Settlement, Shares									1,600,000	4,400,000
January 2016 ASR [Domain] | Open market [Domain]
Open Market Repurchases [Abstract]
Average share price									$ 28.55	$ 27.28
Open market [Domain]
Open Market Repurchases [Abstract]
Total number of shares repurchased									19,500,000	28,400,000