Business segment information - Schedule of Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Jun. 30, 2025
Segment Reporting Information [Line Items]
Net sales	$ 5,174	$ 4,743	$ 10,258	$ 9,647
Other Segment Items	3,939	3,695	7,791	7,492
Segment operating income	1,182	992	2,365	2,050
Corporate general and administrative expenses	837	782	1,710	1,631
Interest expense	106	101	207	214
Other expense (income), net	12	(275)	54	(205)
Income before income taxes	1,064	1,166	2,104	2,041
Assets	30,511		30,511		$ 29,494
Property Additions	94	121	183	216
Depreciation	85	88	177	177
Amortization	148	138	288	278
Diversified Industrial
Segment Reporting Information [Line Items]
Net sales	3,468	3,253	6,911	6,709
Aerospace Systems
Segment Reporting Information [Line Items]
Net sales	1,706	1,490	3,347	2,938
Investment in a joint venture	222		222		226
Operating Segments
Segment Reporting Information [Line Items]
Segment operating income	1,235	1,048	2,467	2,155
Operating Segments | Diversified Industrial
Segment Reporting Information [Line Items]
Net sales	3,468	3,253	6,911	6,709
Other Segment Items	2,676	2,543	5,298	5,215
Segment operating income	792	710	1,613	1,494
Assets	16,881		16,881		15,953
Property Additions	69	99	143	174
Depreciation	59	56	118	115
Amortization	73	63	137	128
Operating Segments | Aerospace Systems
Segment Reporting Information [Line Items]
Net sales	1,706	1,490	3,347	2,938
Other Segment Items	1,263	1,152	2,493	2,277
Segment operating income	443	338	854	661
Assets	12,204		12,204		12,218
Property Additions	22	21	34	35
Depreciation	23	28	53	56
Amortization	75	75	151	150
Corporate
Segment Reporting Information [Line Items]
Corporate general and administrative expenses	53	56	102	105
Assets	1,426		1,426		$ 1,323
Property Additions	3	1	6	7
Depreciation	3	4	6	6
Amortization	$ 0	$ 0	$ 0	$ 0