Consolidated Statements of Earnings (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Revenues:
Investment gains/losses	$ 2,182		$ 4,058		$ 318
Other-than-temporary impairment losses on investments	(908)		(1,973)		(3,155)
Total revenues	143,688		136,185		112,493
Costs and expenses:
Total costs and expenses	128,374		117,134		100,941
Earnings before income taxes	15,314		19,051		11,552
Income tax expense	4,568		5,607		3,538
Earnings from equity method investments			50		427
Net earnings	10,746		13,494		8,441
Less: Earnings attributable to noncontrolling interests	492		527		386
Net earnings attributable to Berkshire Hathaway	10,254		12,967		8,055
Average common shares outstanding	1,649,891	[1]	1,635,661	[1]	1,551,174	[1]
Class A [Member]
Net earnings per share attributable to Berkshire Hathaway shareholders:
Net earnings per share attributable to Berkshire Hathaway shareholders	$ 6,215.00	[1]	$ 7,928.00	[1]	$ 5,193.00	[1]
Insurance and Other [Member]
Revenues:
Insurance premiums earned	32,075		30,749		27,884
Sales and service revenues	72,803		67,225		62,555
Interest, dividend and other investment income	4,792		5,215		5,531
Investment gains/losses	1,973		4,044		358
Other-than-temporary impairment losses on investments	(908)		(1,973)		(3,155)
Total revenues	110,735		105,260		93,173
Costs and expenses:
Insurance losses and loss adjustment expenses	20,829		18,087		18,251
Life, annuity and health insurance benefits	4,879		4,453		1,937
Insurance underwriting expenses	6,119		6,196		6,236
Cost of sales and services	59,839		55,585		52,647
Selling, general and administrative expenses	8,670		7,704		8,117
Interest expense	308		278		189
Total costs and expenses	100,644		92,303		87,377
Railroad, Utilities and Energy [Member]
Revenues:
Operating revenues	30,721		26,186		11,204
Other	118		178		239
Total revenues	30,839		26,364		11,443
Costs and expenses:
Cost of sales and operating expenses	22,736		19,637		8,739
Interest expense	1,703		1,577		1,176
Total costs and expenses	24,439		21,214		9,915
Finance and Financial Products [Member]
Revenues:
Interest, dividend and other investment income	1,618		1,683		1,600
Investment gains/losses	209		14		(40)
Derivative gains/losses	(2,104)		261		3,624
Other	2,391		2,603		2,693
Total revenues	2,114		4,561		7,877
Costs and expenses:
Interest expense	653		703		627
Other	2,638		2,914		3,022
Total costs and expenses	$ 3,291		$ 3,617		$ 3,649

[1] Average shares outstanding include average Class A common shares and average Class B common shares determined on an equivalent Class A common stock basis. Net earnings per common share attributable to Berkshire Hathaway shown above represents net earnings per equivalent Class A common share. Net earnings per Class B common share is equal to one-fifteen-hundredth (1/1,500) of such amount or $4.14 per share for 2011, $5.29 per share for 2010 and $3.46 per share for 2009.