Revenue and segment information - Disaggregation of Net Sales (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2024	Jul. 31, 2023	Jul. 31, 2022
Segment Reporting Information [Line Items]
Total net sales	$ 29,635	$ 29,734	$ 28,566
United States
Segment Reporting Information [Line Items]
Total net sales	28,195	28,291	27,067
Canada
Segment Reporting Information [Line Items]
Total net sales	1,440	1,443	1,499
Residential | United States
Segment Reporting Information [Line Items]
Total net sales	14,464	14,820	14,657
Non-residential: | United States
Segment Reporting Information [Line Items]
Total net sales	13,731	13,471	12,410
Commercial | United States
Segment Reporting Information [Line Items]
Total net sales	9,431	9,213	8,600
Civil/Infrastructure | United States
Segment Reporting Information [Line Items]
Total net sales	2,396	2,344	2,163
Industrial | United States
Segment Reporting Information [Line Items]
Total net sales	$ 1,904	$ 1,914	$ 1,647