Retirement benefit obligations - AOCI (Details) - USD ($) $ in Millions	Jul. 31, 2024	Jul. 31, 2023
Retirement Benefits [Abstract]
Net actuarial loss	$ 617	$ 602
Income tax impact	(147)	(143)
Accumulated other comprehensive loss	$ 470	$ 459

Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Balance Type:	debit
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