Business segment data - Revenues (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 276,094	$ 245,510	$ 254,616
BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	23,177	20,750	23,357
Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	24,943	21,014	20,096
Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	68,577	58,978	62,624
McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	49,450	46,840	50,458
Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	34,747	28,111	29,399
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	276,421	245,358	253,997
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	69,478	63,401	61,078
Interest, dividend and other investment income	5,662	5,960	6,615
Total revenues	75,140	69,361	67,693
Operating Businesses [Member] | Insurance Group [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Premiums earned	37,706	35,093	35,572
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	20,197	18,693	16,341
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	11,575	9,615	9,165
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	23,282	20,869	23,515
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	24,987	21,031	20,114
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	68,730	59,079	62,730
Operating Businesses [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	49,450	46,840	50,458
Operating Businesses [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	34,832	28,178	29,487
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (327)	$ 152	$ 619