Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 126	$ 1,110	$ 360
Other comprehensive income (loss), net of reclassification adjustments:
Foreign currency translation and other losses	(59)	(26)	77
Unrealized gains (losses) on marketable securities and privately held debt securities	26	(12)	(4)
Other comprehensive income (loss), before tax	(33)	(38)	73
Tax effect	(2)	(1)	1
Other comprehensive income (loss), net	(35)	(39)	74
Comprehensive income	$ 91	$ 1,071	$ 434