Business segment information - Schedule of Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2025
Segment Reporting Information [Line Items]
Net sales	$ 5,084	$ 4,904
Other Segment Items	3,852	3,797
Segment operating income	1,183	1,058
Corporate general and administrative expenses	873	849
Interest expense	101	113
Other expense, net	42	70
Income before income taxes	1,040	875
Assets	30,677		$ 29,494
Property Additions	89	95
Depreciation	92	89
Amortization	140	140
Diversified Industrial
Segment Reporting Information [Line Items]
Net sales	3,443	3,456
Aerospace Systems
Segment Reporting Information [Line Items]
Net sales	1,641	1,448
Investment in a joint venture	225		226
Operating Segments
Segment Reporting Information [Line Items]
Segment operating income	1,232	1,107
Operating Segments | Diversified Industrial
Segment Reporting Information [Line Items]
Net sales	3,443	3,456
Other Segment Items	2,622	2,672
Segment operating income	821	784
Assets	17,079		15,953
Property Additions	74	75
Depreciation	59	59
Amortization	64	65
Operating Segments | Aerospace Systems
Segment Reporting Information [Line Items]
Net sales	1,641	1,448
Other Segment Items	1,230	1,125
Segment operating income	411	323
Assets	12,220		12,218
Property Additions	12	14
Depreciation	30	28
Amortization	76	75
Corporate
Segment Reporting Information [Line Items]
Corporate general and administrative expenses	49	49
Assets	1,378		$ 1,323
Property Additions	3	6
Depreciation	3	2
Amortization	$ 0	$ 0