Costs to Obtain a Contract with a Customer (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2026	Jul. 31, 2025	Jul. 31, 2026	Jul. 31, 2025	Jan. 31, 2026
Capitalized Contract Cost [Line Items]
Costs to obtain a contract	$ 794,000,000		$ 794,000,000		$ 913,000,000
Current liability	368,000,000		368,000,000		$ 550,000,000
Amortization of costs to obtain a contract with a customer		$ 123,000,000	347,000,000	$ 219,000,000
Impairment losses	0	$ 0	0	$ 0
Revision of Prior Period, Reclassification, Adjustment
Capitalized Contract Cost [Line Items]
Amortization of costs to obtain a contract with a customer	$ 175,000,000		$ 347,000,000