Consolidated Statements of Earnings - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Sales and service revenues		$ 175,445
Total revenues		247,837	$ 239,933	$ 215,114
Investment and derivative contract gains (losses):
Investment gains (losses)		(22,155)	1,410	7,553
Derivative contract gains (losses)		(300)	718	751
Investment and derivative gains/losses		(22,455)	2,128	8,304
Costs and expenses:
Interest expense		3,853	4,386	3,741
Total costs and expenses		219,214	221,237	190,860
Earnings before income taxes and equity method earnings (losses)		6,168	20,824	32,558
Equity method earnings (losses)		(2,167)	3,014	1,109
Earnings before income taxes		4,001	23,838	33,667
Income tax expense (benefit)		(321)	(21,515)	9,240
Net earnings		4,322	45,353	24,427
Earnings attributable to noncontrolling interests		301	413	353
Net earnings attributable to Berkshire Hathaway shareholders		$ 4,021	$ 44,940	$ 24,074
Equivalent Class A [Member]
Costs and expenses:
Net earnings per average equivalent share		$ 2,446	$ 27,326	$ 14,645
Average equivalent shares outstanding		1,643,795	1,644,615	1,643,826
Equivalent Class B [Member]
Costs and expenses:
Net earnings per average equivalent share	[1]	$ 1.63	$ 18.22	$ 9.76
Average equivalent shares outstanding		2,465,692,368	2,466,923,163	2,465,739,654
Insurance and Other [Member]
Revenues:
Insurance premiums earned		$ 57,418	$ 60,597	$ 45,881
Sales and service revenues		133,336	130,343	123,053
Leasing revenues		5,732	2,452	2,553
Interest, dividend and other investment income		7,678	6,536	6,180
Total revenues		204,164	199,928	177,667
Costs and expenses:
Insurance losses and loss adjustment expenses		39,906	48,891	30,906
Life, annuity and health insurance benefits		5,699	5,618	5,131
Insurance underwriting expenses		9,793	9,321	7,713
Cost of sales and services		106,083	104,343	97,867
Cost of leasing		4,061	1,455	1,335
Selling, general and administrative expenses		18,238	19,189	17,973
Interest expense		1,035	1,132	1,099
Total costs and expenses		184,815	189,949	162,024
Railroad [Member]
Revenues:
Total revenues		23,703	21,080	19,683
Costs and expenses:
Freight rail transportation expenses		16,045	14,031	13,134
Utilities and Energy [Member]
Revenues:
Sales and service revenues		15,555	15,155	14,621
Costs and expenses:
Cost of sales and other expenses		11,641	10,772	10,471
Railroad, Utilities and Energy [Member]
Revenues:
Service revenues and other income		4,415	3,770	3,143
Total revenues		43,673	40,005	37,447
Costs and expenses:
Other expenses		3,895	3,231	2,589
Interest expense		2,818	3,254	2,642
Total costs and expenses		$ 34,399	$ 31,288	$ 28,836

[1] Class B shares are economically equivalent to one-fifteen-hundredth of a Class A share. Accordingly, net earnings per average equivalent Class B share outstanding is equal to one-fifteen-hundredth of the equivalent Class A amount. See Note 21.