Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Jan. 31, 2018 USD ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)	Feb. 01, 2018 USD ($)	Jan. 31, 2015 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Customers per week, approximate	270,000,000
Number of stores	11,700
Banners	65
Number of countries	28
Amounts due from banks	$ 1,600	$ 1,500
Restricted cash and cash equivalents	300	265
Cash and cash equivalents	6,756	6,867	$ 8,705		$ 9,135
Cash held in foreign countries	6,800	5,900
Nonrepatriable cash and cash equivalents	1,400	1,000
Depreciation and amortization of property and equipment, property under financing obligations and property under capital leases	10,500	10,100	9,500
Advertising expense	3,100	2,900	2,500
Pre-opening costs	106	$ 131	$ 271
Other Noncurrent Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash recorded as noncurrent asset	$ 258
Subsequent Event [Member] | Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative adjustment to retained earnings				$ 2,900