Financial Instruments - Narrative (Details) - USD ($)	12 Months Ended
	Jan. 31, 2026	Jan. 31, 2025	Jan. 31, 2024
Investments, All Other Investments [Abstract]
Securities in continuous unrealized loss position for greater than twelve months	$ 0	$ 0
Allowance for credit loss	0	0
Write offs of accrued interest receivables	0	0
Available-for-sale securities gross gains (losses)	$ 0	$ 0	$ 0
Derivative Gain Loss Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag	Interest and other income, net	Interest and other income, net	Interest and other income, net
Direct investments in privately held companies	$ 346,000,000	$ 168,000,000