Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 29, 2017	Apr. 30, 2016		Jan. 28, 2017	Jan. 30, 2016
Significant Accounting Policies [Line Items]
Shares of common stock repurchased to satisfy tax withholding obligations	$ 9	$ 6	[1]
Accounting Standards Update 2016-09 [Member]
Significant Accounting Policies [Line Items]
Excess tax benefits on share-based compensation, operating activities	7	6
Shares of common stock repurchased to satisfy tax withholding obligations		6
Accounting Standards Update 2016-18 [Member]
Significant Accounting Policies [Line Items]
Restricted cash		$ 28		$ 27	$ 27
Maximum [Member] | Scenario, Forecast [Member] | Accounting Standards Update 2016 02 [Member]
Significant Accounting Policies [Line Items]
Addition to assets and liabilities from accounting standards update	4,000
Maximum [Member] | Scenario, Forecast [Member] | Accounting Standards Update 2016 16 [Member]
Significant Accounting Policies [Line Items]
Increase in deferred tax assets	40
Minimum [Member] | Scenario, Forecast [Member] | Accounting Standards Update 2016 02 [Member]
Significant Accounting Policies [Line Items]
Addition to assets and liabilities from accounting standards update	3,000
Minimum [Member] | Scenario, Forecast [Member] | Accounting Standards Update 2016 16 [Member]
Significant Accounting Policies [Line Items]
Increase in deferred tax assets	$ 30

[1] Amounts for the three months ended April 30, 2016 have been revised from previously reported amounts to reflect the adoption of new accounting standards in the first quarter of 2017. For additional information, see the Recently Adopted Accounting Pronouncements note.