Consolidated Statements of Earnings - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Investment gains/losses		$ 657	$ 3,150	$ 1,262	$ 5,643
Total revenues		60,525	58,843	183,230	165,260
Costs and expenses:
Insurance losses and loss adjustment expenses				39,450	22,325
Total costs and expenses		55,147	48,543	166,583	141,578
Earnings before income taxes and equity in earnings of The Kraft Heinz Company		5,378	10,300	16,647	23,682
Equity in earnings of The Kraft Heinz Company		252	225	800	671
Earnings before income taxes		5,630	10,525	17,447	24,353
Income tax expense		1,427	3,192	4,750	6,281
Net earnings		4,203	7,333	12,697	18,072
Less: Earnings attributable to noncontrolling interests		136	135	308	284
Net earnings attributable to Berkshire Hathaway shareholders		$ 4,067	$ 7,198	$ 12,389	$ 17,788
Equivalent Class A [Member]
Net earnings per share attributable to Berkshire Hathaway shareholders:
Net earnings per share attributable to Berkshire Hathaway shareholders	[1]	$ 2,473	$ 4,379	$ 7,533	$ 10,822
Average equivalent Class A Shares outstanding	[1]	1,644,656	1,643,913	1,644,554	1,643,716
Insurance and Other [Member]
Revenues:
Insurance premiums earned		$ 13,349	$ 11,364	$ 47,469	$ 33,287
Sales and service revenues		32,055	30,536	94,017	89,357
Interest, dividend and other investment income		1,320	1,051	3,804	3,613
Investment gains/losses		457	735	1,056	3,221
Total revenues		47,181	43,686	146,346	129,478
Costs and expenses:
Insurance losses and loss adjustment expenses		12,137	7,615	39,450	22,325
Life, annuity and health insurance benefits		1,213	1,339	3,703	3,747
Insurance underwriting expenses		2,207	2,001	6,924	5,948
Cost of sales and services		25,815	24,472	75,594	71,617
Selling, general and administrative expenses		3,965	3,959	12,101	11,747
Interest expense		435	259	1,405	674
Total costs and expenses		45,772	39,645	139,177	116,058
Railroad, Utilities and Energy [Member]
Revenues:
Total revenues		10,652	10,330	29,899	28,026
Costs and expenses:
Cost of sales and operating expenses		6,984	6,763	20,678	19,421
Interest expense		700	681	2,090	1,962
Total costs and expenses		7,684	7,444	22,768	21,383
Finance and Financial Products [Member]
Revenues:
Sales and service revenues		1,824	1,588	5,002	4,557
Interest, dividend and other investment income		360	366	1,074	1,109
Investment gains/losses		200	2,415	206	2,422
Derivative gains/losses		308	458	703	(332)
Total revenues		2,692	4,827	6,985	7,756
Costs and expenses:
Cost of sales and services		1,062	886	2,891	2,529
Selling, general and administrative expenses		531	465	1,442	1,301
Interest expense		98	103	305	307
Total costs and expenses		$ 1,691	$ 1,454	$ 4,638	$ 4,137

[1] Equivalent Class B shares outstanding are 1,500 times the equivalent Class A amount. Net earnings per equivalent Class B share outstanding are one-fifteen-hundredth (1/1,500) of the equivalent Class A amount.