Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 28, 2018		Jan. 29, 2017	Jan. 31, 2016
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 413
Unrecognized tax benefit related to state tax positions	58
Reduction of deferred tax asset included in unrecognized tax benefit	238
unrecognized tax benefit (non current)	175
Income Tax Reconciliation, Tax Contingencies [Abstract]
Balance at beginning of period	224		$ 230	$ 254
Increases in tax positions for prior years	7		3	0
Decreases in tax positions for prior years	(1)		0	(1)
Increases in tax positions for current year	222		46	28
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0		(48)	0
Lapse in statute of limitations	(5)		(7)	(51)
Balance at end of period	447		224	230
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	15		13	$ 11
Accrued Income Taxes, Noncurrent	$ 559	[1]	$ 96

[1] .