Business segment data - Revenues (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 70,810	$ 64,599
BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	5,944	5,378
Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	5,978	5,924
Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	18,385	15,880
McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	12,514	11,622
Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,091	7,943
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	70,858	64,656
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income	1,364	1,414
Total revenues	18,856	17,838
Operating Businesses [Member] | Insurance Group [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Premiums earned	9,554	8,923
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	4,820	4,847
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	3,118	2,654
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	5,968	5,401
Operating Businesses [Member] | Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Total revenues	5,983	5,924
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	18,421	15,913
Operating Businesses [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	12,515	11,622
Operating Businesses [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,115	7,958
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (48)	$ (57)