Investments - Gains (Losses) on Strategic Investments, Net (Details) - USD ($) $ in Millions		12 Months Ended
		Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Investment Holdings [Line Items]
Net unrealized gains (loss) recognized		$ 1,800	$ 300
Gains on strategic investments, net	[1]	2,170	427	$ 542
Publicly traded securities
Investment Holdings [Line Items]
Net unrealized gains (loss) recognized		1,743	138	345
Privately held securities
Investment Holdings [Line Items]
Net unrealized gains (loss) recognized		77	208	133
Equity securities
Investment Holdings [Line Items]
Net realized gains (losses) recognized		367	95	74
Debt securities
Investment Holdings [Line Items]
Net realized gains (losses) recognized		$ (17)	$ (14)	$ (10)

[1] During fiscal 2021, two of the Company’s strategic investments completed their initial public offering, resulting in an unrealized gain of $1.7 billion as of January 31, 2021.