Deferred Compensation (Details) - USD ($)	3 Months Ended
	Apr. 30, 2024	Apr. 30, 2023	Jan. 31, 2024
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	$ 217,000,000		$ 210,000,000
Amortization of costs to obtain a contract with a customer	41,000,000	$ 30,000,000
Impairment losses	0	$ 0
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	151,000,000
Long-term other assets
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Costs to obtain a contract	66,000,000
Rabbi Trust
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability	107,000,000		100,000,000
Deferred compensation liability, current	10,000,000		10,000,000
Deferred compensation liability, non-current	$ 97,000,000		$ 90,000,000