Consolidated Statements of Earnings - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Sales and service revenues		$ 48,110	$ 37,378	$ 92,733	$ 78,830
Leasing revenues		1,447	1,161	2,771	2,589
Total revenues		69,114	56,840	133,713	118,105
Investment and derivative contract gains (losses)		27,394	40,085	33,094	(30,190)
Costs and expenses:
Total costs and expenses		60,934	61,259	116,956	115,598
Earnings (loss) before income taxes and equity method earnings		35,574	35,666	49,851	(27,683)
Equity method earnings (loss)		147	(257)	398	43
Earnings (loss) before income taxes		35,721	35,409	50,249	(27,640)
Income tax expense (benefit)		7,296	9,002	9,984	(4,350)
Net earnings (loss)		28,425	26,407	40,265	(23,290)
Earnings attributable to noncontrolling interests		331	112	460	161
Net earnings (loss) attributable to Berkshire Hathaway shareholders		$ 28,094	$ 26,295	$ 39,805	$ (23,451)
Equivalent Class A [Member]
Costs and expenses:
Net earnings (loss) per average equivalent share		$ 18,488	$ 16,314	$ 26,078	$ (14,500)
Average equivalent shares outstanding		1,519,576	1,611,760	1,526,392	1,617,325
Equivalent Class B [Member]
Costs and expenses:
Net earnings (loss) per average equivalent share	[1]	$ 12.33	$ 10.88	$ 17.39	$ (9.67)
Average equivalent shares outstanding		2,279,363,382	2,417,640,311	2,289,587,640	2,425,986,839
Insurance and Other [Member]
Revenues:
Insurance premiums earned		$ 17,163	$ 15,595	$ 33,587	$ 31,343
Sales and service revenues		36,743	28,703	70,441	60,629
Leasing revenues		1,447	1,161	2,771	2,589
Interest, dividend and other investment income		1,898	2,150	3,749	4,426
Total revenues		57,251	47,609	110,548	98,987
Costs and expenses:
Insurance losses and loss adjustment expenses		12,175	10,066	23,139	21,045
Life, annuity and health insurance benefits		1,459	1,407	2,939	2,790
Insurance underwriting expenses		3,065	3,067	6,079	5,991
Cost of sales and services		28,761	23,216	55,291	48,608
Cost of leasing		982	749	1,864	1,751
Selling, general and administrative expenses		5,045	4,652	8,955	9,123
Goodwill and intangible asset impairments			10,634		10,634
Interest expense		298	258	574	554
Total costs and expenses		51,785	54,049	98,841	100,496
Freight Rail Transportation [Member]
Revenues:
Total revenues		5,778	4,573	11,156	9,953
Costs and expenses:
Expenses		3,588	2,871	7,098	6,464
Utilities and Energy [Member]
Revenues:
Sales and service revenues		4,302	3,419	9,150	7,053
Costs and expenses:
Cost of sales and other expenses		3,220	2,503	6,809	5,225
Railroad, Utilities and Energy [Member]
Revenues:
Service revenues and other income		1,783	1,239	2,859	2,112
Total revenues		11,863	9,231	23,165	19,118
Costs and expenses:
Other expenses		1,563	1,092	2,656	1,941
Interest expense		778	744	1,552	1,472
Total costs and expenses		$ 9,149	$ 7,210	$ 18,115	$ 15,102

[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 17.