Business segment data - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Sales	$ 364,482	$ 302,020	$ 276,185
Sales, Service and Leasing Revenues [Member]
Segment Reporting Information [Line Items]
Sales	$ 164,100	$ 165,000	$ 151,000
United States [Member] | Geographic Concentration [Member] | Sales, Service and Leasing Revenues [Member]
Segment Reporting Information [Line Items]
Concentration percentage	85.00%	86.00%	85.00%
United States [Member] | Geographic Concentration [Member] | Property, Plant and Equipment and Equipment Held for Lease [Member]
Segment Reporting Information [Line Items]
Concentration percentage	90.00%
Railroad, Utilities and Energy [Member]
Segment Reporting Information [Line Items]
Sales	$ 101,415	$ 52,149	$ 48,229
Railroad, Utilities and Energy [Member] | United States [Member] | Geographic Concentration [Member] | Revenues [Member]
Segment Reporting Information [Line Items]
Concentration percentage	94.00%	96.00%	96.00%