Business segment data - Additional tabular disclosures (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Interest expense		$ 5,200	$ 5,003	$ 4,352
Income tax expense		20,815	23,019	(8,502)
Depreciation and amortization		12,855	12,486	10,899
Goodwill at year-end	[1]	83,880	84,626	78,119
Assets		1,153,881	1,069,978	948,465
Business Segments [Member]
Segment Reporting Information [Line Items]
Interest expense		4,982	4,630	3,946
Income tax expense		8,870	6,910	4,981
Capital expenditures		18,976	19,409	15,464
Depreciation and amortization		12,208	11,667	10,082
Goodwill at year-end		83,880	84,626	78,119
Identifiable assets at year-end		932,848	921,210	807,701
Business Segments [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Income tax expense		5,462	3,497	1,247
Capital expenditures		99	68	82
Depreciation and amortization		411	401	260
Goodwill at year-end		16,557	16,563	16,548
Identifiable assets at year-end		539,884	538,860	459,917
Business Segments [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Interest expense		1,078	1,048	1,025
Income tax expense		1,617	1,527	1,763
Capital expenditures		3,690	3,920	3,532
Depreciation and amortization		2,621	2,627	2,510
Goodwill at year-end		15,351	15,350	14,852
Identifiable assets at year-end		80,813	79,227	77,752
Business Segments [Member] | Berkshire Hathaway Energy ("BHE") [Member]
Segment Reporting Information [Line Items]
Interest expense		2,528	2,283	2,140
Income tax expense		(1,871)	(2,022)	(1,629)
Capital expenditures		9,013	9,148	7,505
Depreciation and amortization		4,003	4,010	3,751
Goodwill at year-end		11,669	11,804	11,745
Identifiable assets at year-end		128,276	124,383	118,114
Business Segments [Member] | Pilot [Member]
Segment Reporting Information [Line Items]
Interest expense		302	414
Income tax expense			169
Capital expenditures		799	705
Depreciation and amortization		1,012	796
Goodwill at year-end		6,477	6,605
Identifiable assets at year-end		19,652	21,404
Business Segments [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Interest expense		934	784	739
Income tax expense		2,598	2,487	2,403
Capital expenditures		2,779	2,714	2,477
Depreciation and amortization		2,422	2,290	2,140
Goodwill at year-end		27,716	27,831	28,460
Identifiable assets at year-end		119,860	115,875	113,578
Business Segments [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Interest expense		22
Income tax expense		152	117	66
Capital expenditures		236	264	93
Depreciation and amortization		217	208	176
Goodwill at year-end		232	232	232
Identifiable assets at year-end		7,165	6,861	7,049
Business Segments [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Interest expense		118	101	42
Income tax expense		912	1,135	1,131
Capital expenditures		2,360	2,590	1,775
Depreciation and amortization		1,522	1,335	1,245
Goodwill at year-end		5,878	6,241	6,282
Identifiable assets at year-end		37,198	34,600	31,291
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Interest expense		427	426	420
Investment gains (losses), tax		11,179	15,930	(14,166)
Interest expense, not allocated to segments, tax		(90)	(90)	(88)
Non-controlled businesses, tax		322	223	334
Goodwill at year-end		83,880	84,626	78,119
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Interest expense		(209)	(53)	(14)
Income tax expense		534	46	437
Depreciation and amortization		647	819	817
Identifiable assets at year-end		$ 137,153	$ 64,142	$ 62,645

[1] Net of accumulated goodwill impairments of $11.5 billion as of December 31, 2024, $11.1 billion as of December 31, 2023 and $11.0 billion as of December 31, 2022.