Business segment data - Earnings data (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues		$ 371,433	$ 364,482	$ 302,020
Costs and Expenses:
Interest expense		5,200	5,003	4,352
Total costs and expenses		315,697	321,144	266,484
Earnings (loss) before income taxes		110,376	120,166	(30,500)
BNSF [Member]
Segment Reporting Information [Line Items]
Revenues		23,490	23,791	25,802
BHE [Member]
Segment Reporting Information [Line Items]
Revenues		26,300	25,960	26,347
Manufacturing [Member]
Segment Reporting Information [Line Items]
Revenues		77,148	75,283	75,650
Service and Retailing [Member]
Segment Reporting Information [Line Items]
Revenues		39,783	39,879	38,209
Pilot [Member]
Segment Reporting Information [Line Items]
Revenues	[1]	46,856	51,664
McLane [Member]
Segment Reporting Information [Line Items]
Revenues		51,086	51,814	53,209
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Revenues		370,892	364,653	301,884
Costs and Expenses:
Interest expense		4,982	4,630	3,946
Earnings (loss) before income taxes		53,936	43,637	34,775
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Revenues		105,069	95,022	82,310
Costs and Expenses:
Losses and LAE		56,186	57,187	57,646
Life, annuity and health benefits		3,858	4,029	5,243
Other segment items		16,872	15,312	11,719
Total costs and expenses		76,916	76,528	74,608
Earnings (loss) before income taxes		28,153	18,494	7,702
Operating Businesses [Member] | Insurance Group [Member] | Underwriting [Member]
Segment Reporting Information [Line Items]
Revenues		88,257	83,403	74,576
Costs and Expenses:
Losses and LAE		56,186	57,187	57,646
Life, annuity and health benefits		3,858	4,029	5,243
Other segment items		16,808	15,274	11,709
Total costs and expenses		76,852	76,490	74,598
Earnings (loss) before income taxes		11,405	6,913	(22)
Operating Businesses [Member] | Insurance Group [Member] | Underwriting [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Revenues		42,252	39,264	38,984
Costs and Expenses:
Losses and LAE		30,331	31,814	36,297
Other segment items		4,108	3,815	4,567
Total costs and expenses		34,439	35,629	40,864
Earnings (loss) before income taxes		7,813	3,635	(1,880)
Operating Businesses [Member] | Insurance Group [Member] | Underwriting [Member] | BH Primary [Member]
Segment Reporting Information [Line Items]
Revenues		18,733	17,129	13,746
Costs and Expenses:
Losses and LAE		12,666	11,224	9,889
Other segment items		5,212	4,531	3,464
Total costs and expenses		17,878	15,755	13,353
Earnings (loss) before income taxes		855	1,374	393
Operating Businesses [Member] | Insurance Group [Member] | Underwriting [Member] | BHRG [Member]
Segment Reporting Information [Line Items]
Revenues		27,272	27,010	21,846
Costs and Expenses:
Losses and LAE		13,189	14,149	11,460
Life, annuity and health benefits		3,858	4,029	5,243
Other segment items		7,488	6,928	3,678
Total costs and expenses		24,535	25,106	20,381
Earnings (loss) before income taxes		2,737	1,904	1,465
Operating Businesses [Member] | Insurance Group [Member] | Investment Income [Member]
Segment Reporting Information [Line Items]
Revenues		16,812	11,619	7,734
Costs and Expenses:
Other segment items		64	38	10
Total costs and expenses		64	38	10
Earnings (loss) before income taxes		16,748	11,581	7,724
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Revenues		23,572	23,876	25,888
Costs and Expenses:
Compensation and benefits		5,872	5,551	5,321
Fuel		3,267	3,684	4,581
Depreciation and amortization		2,621	2,627	2,510
Interest expense		1,078	1,048	1,025
Other segment items		4,086	4,352	4,743
Total costs and expenses		16,924	17,262	18,180
Earnings (loss) before income taxes		6,648	6,614	7,708
Operating Businesses [Member] | BHE [Member]
Segment Reporting Information [Line Items]
Revenues		26,348	26,008	26,393
Costs and Expenses:
Energy Cost of Sales		6,616	7,057	6,757
Energy Operations and Maintenance		5,470	6,456	4,216
Energy Depreciation and Amortization		3,957	3,960	3,695
Real Estate Costs and Expenses		4,509	4,316	5,117
Interest expense		2,528	2,283	2,140
Other segment items		976	996	1,322
Total costs and expenses		24,056	25,068	23,247
Earnings (loss) before income taxes		2,292	940	3,146
Operating Businesses [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Revenues		77,231	75,405	75,781
Costs and Expenses:
Cost of sales and services		50,702	50,389	52,297
Cost of leasing		1,142	1,051	1,083
Interest expense		934	784	739
Other segment items		12,558	11,736	10,485
Total costs and expenses		65,336	63,960	64,604
Earnings (loss) before income taxes		11,895	11,445	11,177
Operating Businesses [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Revenues		39,874	39,996	38,303
Costs and Expenses:
Cost of sales and services		23,818	23,915	22,952
Cost of leasing		5,917	5,011	4,462
Interest expense		118	101	42
Other segment items		6,321	6,248	6,076
Total costs and expenses		36,174	35,275	33,532
Earnings (loss) before income taxes		3,700	4,721	4,771
Operating Businesses [Member] | Pilot [Member]
Segment Reporting Information [Line Items]
Revenues		46,891	51,739
Costs and Expenses:
Cost of sales and services		42,591	47,505
Depreciation and amortization		1,012	796
Interest expense		302	414
Other segment items		2,674	2,470
Total costs and expenses		46,277	50,771
Earnings (loss) before income taxes		614	968
Operating Businesses [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Revenues		51,907	52,607	53,209
Costs and Expenses:
Cost of sales and services		47,604	48,495	49,236
Depreciation and amortization		217	208	176
Interest expense		22
Other segment items		3,452	3,449	3,526
Total costs and expenses		51,273	52,152	52,938
Earnings (loss) before income taxes		$ 634	$ 455	$ 271

[1] Revenues from Pilot are principally fuel sales and revenues in 2023 are for the eleven months ending December 31.