Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2025	Jul. 31, 2024	Jul. 31, 2025	Jul. 31, 2024
Effective Income Tax Rate Reconciliation [Line Items]
Provision for (benefit from) income taxes	$ 0	$ (17)	$ 6	$ 1
Pretax income (loss)	$ 67	$ 12	$ 135	$ (10)
Effective income tax rate	0.50%		4.60%
One Big Beautiful Bill Act, income tax benefit	$ 5
Netting
Effective Income Tax Rate Reconciliation [Line Items]
Effective income tax rate		(158.80%)		(2.50%)