Income Taxes - Provisions For (Benefit From) (Details) - USD ($) $ in Millions		12 Months Ended
		Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Current:
Federal		$ 8	$ 0	$ (7)
State		33	39	2
Foreign		512	117	85
Total		553	156	80
Deferred:
Federal		(41)	(248)	(2)
State		8	(37)	(14)
Foreign		60	2	(4)
Total		27	(283)	(20)
Provision for (benefit from) income taxes	[1]	$ 580	$ (127)	$ 60

[1] Amounts include a benefit related to the partial release of the valuation allowance of $612 million, and $2 million, for fiscal 2019 and 2018, respectively. The fiscal 2019 benefit was partially offset by an increase in unrecognized tax benefits.