Consolidated Statements of Earnings - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Sales and service revenues		$ 176,512	$ 175,445
Total revenues		254,616	247,837	$ 239,933
Investment and derivative contract gains (losses):
Investment gains (losses)		71,123	(22,155)	1,410
Derivative contract gains (losses)		1,484	(300)	718
Investment and derivative gains/losses		72,607	(22,455)	2,128
Costs and expenses:
Interest expense		3,961	3,853	4,386
Total costs and expenses		225,703	219,214	221,237
Earnings before income taxes and equity method earnings (losses)		101,520	6,168	20,824
Equity method earnings (losses)		1,176	(2,167)	3,014
Earnings before income taxes		102,696	4,001	23,838
Income tax expense (benefit)		20,904	(321)	(21,515)
Net earnings		81,792	4,322	45,353
Earnings attributable to noncontrolling interests		375	301	413
Net earnings attributable to Berkshire Hathaway shareholders		$ 81,417	$ 4,021	$ 44,940
Equivalent Class A [Member]
Costs and expenses:
Net earnings per average equivalent share		$ 49,828	$ 2,446	$ 27,326
Average equivalent shares outstanding		1,633,946	1,643,795	1,644,615
Equivalent Class B [Member]
Costs and expenses:
Net earnings per average equivalent share	[1]	$ 33.22	$ 1.63	$ 18.22
Average equivalent shares outstanding		2,450,919,020	2,465,692,368	2,466,923,163
Insurance and Other [Member]
Revenues:
Insurance premiums earned		$ 61,078	$ 57,418	$ 60,597
Sales and service revenues		134,989	133,336	130,343
Leasing revenues		5,856	5,732	2,452
Interest, dividend and other investment income		9,240	7,678	6,536
Total revenues		211,163	204,164	199,928
Costs and expenses:
Insurance losses and loss adjustment expenses		44,456	39,906	48,891
Life, annuity and health insurance benefits		4,986	5,699	5,618
Insurance underwriting expenses		11,200	9,793	9,321
Cost of sales and services		107,041	106,083	104,343
Cost of leasing		4,003	4,061	1,455
Selling, general and administrative expenses		19,322	18,238	19,189
Interest expense		1,056	1,035	1,132
Total costs and expenses		192,064	184,815	189,949
Freight Rail Transportation [Member]
Revenues:
Total revenues		23,357	23,703	21,080
Costs and expenses:
Expenses		15,436	16,045	14,031
Utilities and Energy [Member]
Revenues:
Sales and service revenues		15,353	15,555	15,155
Costs and expenses:
Cost of sales and other expenses		11,296	11,641	10,772
Railroad, Utilities and Energy [Member]
Revenues:
Service revenues and other income		4,743	4,415	3,770
Total revenues		43,453	43,673	40,005
Costs and expenses:
Other expenses		4,002	3,895	3,231
Interest expense		2,905	2,818	3,254
Total costs and expenses		$ 33,639	$ 34,399	$ 31,288

[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.