Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Reconciliation of changes in unrecognized tax benefits
Balance at beginning of period	$ 469	$ 410	$ 370
Gross increases related to prior period tax positions	11	30	33
Gross decreases related to prior period tax positions	(144)	(13)	(88)
Gross increases related to current period tax positions	55	59	114
Settlements with taxing authorities	(12)	(9)	(9)
Lapse of statute of limitations	(5)	(8)	(10)
Balance at end of period	374	469	410
Unrecognized tax benefits that would impact the effective tax rate if recognized	346	337	297
Interest expense recognized as component of income tax expense	9
Accrued interest in income tax expense	61	89	78
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 1	$ 1	$ 2