Summary of Significant Accounting Policies - Adopted Accounting Pronouncements ASU 2014-09 (Earnings) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Feb. 02, 2019		Nov. 03, 2018		Aug. 04, 2018		May 05, 2018		Feb. 03, 2018		Oct. 28, 2017		Jul. 29, 2017		Apr. 29, 2017		Feb. 02, 2019		Feb. 03, 2018		Jan. 28, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 14,801		$ 9,590		$ 9,379		$ 9,109		$ 15,363		$ 9,320		$ 8,940		$ 8,528		$ 42,879		$ 42,151		$ 39,403
Cost of goods sold																	32,918		32,275		29,963
Gross profit	3,283		2,324		2,229		2,125		3,421		2,280		2,153		2,022		9,961		9,876		9,440
Operating income	978	[1]	322	[1]	335	[1]	265	[1]	872	[2]	350	[2]	321	[2]	300	[2]	1,900	[1]	1,843	[2]	1,854
Income tax expense																	424		818		609
Net earnings	$ 735	[3]	$ 277	[3]	$ 244	[3]	$ 208	[3]	$ 364		$ 239		$ 209		$ 188		$ 1,464	[3]	$ 1,000		$ 1,228
Basic earnings per share																	$ 5.30		$ 3.33		$ 3.86
Diluted earnings per share	$ 2.69	[4]	$ 0.99	[4]	$ 0.86	[4]	$ 0.72	[4]	$ 1.23	[4]	$ 0.78	[4]	$ 0.67	[4]	$ 0.60	[4]	$ 5.20	[4]	$ 3.26	[4]	$ 3.81
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue																	$ 42,830
Cost of goods sold																	32,860
Gross profit																	9,970
Operating income																	1,909
Income tax expense																	426
Net earnings																	$ 1,471
Basic earnings per share																	$ 5.32
Diluted earnings per share																	$ 5.23
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Adoption of ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue																	$ 49
Cost of goods sold																	58
Gross profit																	(9)
Operating income																	(9)
Income tax expense																	(2)
Net earnings																	$ (7)
Basic earnings per share																	$ (0.02)
Diluted earnings per share																	$ (0.03)

[1] (2)Includes $30 million, $17 million, $0 million and $(1) million of restructuring charges (benefit) recorded in the fiscal first, second, third and fourth quarters of 2019, respectively, and $46 million for the fiscal year ended February 2, 2019, related to measures we took to restructure our businesses. Also includes $13 million of acquisition-related transaction costs in the fiscal third quarter of 2019 and $5 million and $17 million of non-cash amortization of definite-lived intangible assets in the fiscal third and fourth quarters of 2019, respectively, associated with the acquisition of GreatCall. Total non-cash amortization of definite-lived intangible assets for the fiscal year ended February 2, 2019 was $22 million. The fiscal first quarter and year ended February 2, 2019, also includes $7 million related to the one-time bonus for certain employees in response to future tax savings created by the Tax Act.

[2] (5)Includes $0 million, $2 million, $(2) million and $10 million of restructuring charges (benefit) recorded in the fiscal first, second, third and fourth quarters of 2018, respectively, and $10 million for the fiscal year ended February 3, 2018, related to measures we took to restructure our businesses. Also includes $80 million related to a one-time bonus for certain employees and $20 million related to a one-time contribution to the Best Buy Foundation in response to future tax savings created by the Tax Act for the fiscal fourth quarter and year ended February 3, 2018.

[3] (3)Includes subsequent adjustments resulting from the Tax Act, including $(18) million, $(2) million and $(20) million associated with the deemed repatriation tax recorded in the fiscal third quarter, fourth quarter and year ended February 2, 2019, respectively, and$(5) million and $(5) million related to the revaluation of deferred tax assets and liabilities recorded in the fiscal third quarter and year ended February 2, 2019, respectively.

[4] (4)The sum of our quarterly diluted earnings per share does not equal our annual diluted earnings per share due to differences in quarterly and annual weighted-average shares outstanding.