Business segment data - Revenues (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 76,934	$ 70,583	$ 223,924	$ 204,296
BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	6,663	5,761	19,219	16,917
Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	7,527	7,013	20,018	19,022
Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	18,969	17,456	57,090	50,711
McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	13,570	12,612	39,346	36,529
Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,541	8,654	28,225	25,551
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	76,853	70,656	223,891	204,512
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income	1,683	1,339	5,331	4,212
Total revenues	20,493	19,066	59,720	55,526
Operating Businesses [Member] | Insurance Group [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Premiums earned	9,808	9,604	29,169	28,073
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	5,517	5,159	15,304	14,868
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	3,485	2,964	9,916	8,373
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	6,693	5,790	19,301	17,000
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	7,531	7,013	20,032	19,022
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	19,000	17,496	57,193	50,821
Operating Businesses [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	13,569	12,612	39,346	36,529
Operating Businesses [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,567	8,679	28,299	25,614
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 81	$ (73)	$ 33	$ (216)