Accumulated other comprehensive loss - Schedule of Change in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2025	Jul. 31, 2024	Jul. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 5,616	$ 5,037
Other comprehensive loss before reclassifications	(51)	(54)	$ (66)
Amounts reclassified from accumulated other comprehensive loss	11	11	8
Total other comprehensive loss, net of tax	(40)	(43)	(58)
Ending balance	5,832	5,616	5,037
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(931)	(888)	(830)
Total other comprehensive loss, net of tax	(40)	(43)	(58)
Ending balance	(971)	(931)	(888)
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(461)	(429)	(420)
Other comprehensive loss before reclassifications	(2)	(32)	(9)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Total other comprehensive loss, net of tax	(2)	(32)	(9)
Ending balance	(463)	(461)	(429)
Pensions
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(470)	(459)	(410)
Other comprehensive loss before reclassifications	(49)	(22)	(57)
Amounts reclassified from accumulated other comprehensive loss	11	11	8
Total other comprehensive loss, net of tax	(38)	(11)	(49)
Ending balance	$ (508)	$ (470)	$ (459)