Deferred Compensation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2025	Oct. 31, 2024	Oct. 31, 2025	Oct. 31, 2024	Jan. 31, 2025
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	$ 755,000,000		$ 755,000,000		$ 467,000,000
Amortization of costs to obtain a contract with a customer	145,000,000	$ 51,000,000	364,000,000	$ 136,000,000
Impairment losses	0	0	0	0
Revision of Prior Period, Reclassification, Adjustment
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Amortization of costs to obtain a contract with a customer	145,000,000	$ 51,000,000	364,000,000	$ 136,000,000
Prepaid Expenses and Other Current Assets
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	417,000,000		417,000,000
Long-term other assets
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	338,000,000		338,000,000
Rabbi Trust
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability	139,000,000		139,000,000		118,000,000
Deferred compensation liability, current	14,000,000		14,000,000		12,000,000
Deferred compensation liability, non-current	$ 125,000,000		$ 125,000,000		$ 106,000,000