Deferred Compensation (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2025	Jul. 31, 2024	Jul. 31, 2025	Jul. 31, 2024	Jan. 31, 2025
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	$ 692,000,000		$ 692,000,000		$ 467,000,000
Amortization of costs to obtain a contract with a customer	123,000,000	$ 44,000,000	219,000,000	$ 85,000,000
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	123,000,000	$ 44,000,000	219,000,000	$ 85,000,000
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	377,000,000		377,000,000
Long-term other assets
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	315,000,000		315,000,000
Rabbi Trust
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability	130,000,000		130,000,000		118,000,000
Deferred compensation liability, current	13,000,000		13,000,000		12,000,000
Deferred compensation liability, non-current	$ 117,000,000		$ 117,000,000		$ 106,000,000