Financial Instruments - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021	Jan. 31, 2022
Investments, All Other Investments [Abstract]
Securities in continuous unrealized loss position for greater than twelve months	$ 0		$ 0		$ 0
Allowance for credit loss	0		0		0
Securities, writeoff			0	$ 0
Available-for-sale securities gross gains (losses)			0	0
Direct investments in privately held companies	173,000,000		173,000,000		$ 134,000,000
Equity method investment, realized gain (loss) on disposal	$ 1,000,000	$ 0	$ 1,000,000	$ 8,000,000