Revenue and segment information - Disaggregation of Net Sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2025	Apr. 30, 2024
Segment Reporting Information [Line Items]
Total net sales	$ 7,621	$ 7,308	$ 22,265	$ 21,689
United States
Segment Reporting Information [Line Items]
Total net sales	7,288	6,974	21,210	20,667
Canada
Segment Reporting Information [Line Items]
Total net sales	333	334	1,055	1,022
Residential | United States
Segment Reporting Information [Line Items]
Total net sales	3,610	3,552	10,728	10,591
Non-residential: | United States
Segment Reporting Information [Line Items]
Total net sales	3,678	3,422	10,482	10,076
Commercial | United States
Segment Reporting Information [Line Items]
Total net sales	2,508	2,337	7,161	6,929
Civil/Infrastructure | United States
Segment Reporting Information [Line Items]
Total net sales	661	599	1,866	1,740
Industrial | United States
Segment Reporting Information [Line Items]
Total net sales	$ 509	$ 486	$ 1,455	$ 1,407