Restructuring expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2025	Apr. 30, 2024
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 70	$ 12	$ 73	$ 20
Severance costs	41
Non-cash branch and facility costs	15
Corporate restructuring expenses
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	2	12	5	20
Business restructuring expenses
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 68	$ 0	$ 68	$ 0