Business segment data - Revenues (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 93,210	$ 76,904	$ 271,106	$ 223,948
BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	5,829	6,663	17,638	19,219
Berkshire Hathaway Energy ("BHE") [Member]
Segment Reporting Information [Line Items]
Total revenues	7,269	7,553	20,058	20,108
Pilot Travel Centers ("PTC") [Member]
Segment Reporting Information [Line Items]
Total revenues	13,145		37,374
Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	19,168	18,969	56,507	57,090
McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	13,279	13,570	38,857	39,346
Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,921	9,541	29,932	28,225
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	93,199	76,823	271,193	223,915
Operating Businesses [Member] | Insurance Group [Member]
Segment Reporting Information [Line Items]
Interest, dividend and other investment income	2,948	1,683	8,258	5,331
Total revenues	24,308	20,437	69,975	59,654
Operating Businesses [Member] | Insurance Group [Member] | GEICO [Member]
Segment Reporting Information [Line Items]
Premiums earned	9,844	9,808	29,184	29,169
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	4,449	3,485	12,643	9,916
Operating Businesses [Member] | Insurance Group [Member] | Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Premiums earned	7,067	5,461	19,890	15,238
Operating Businesses [Member] | BNSF [Member]
Segment Reporting Information [Line Items]
Total revenues	5,847	6,693	17,694	19,301
Operating Businesses [Member] | Berkshire Hathaway Energy ("BHE") [Member]
Segment Reporting Information [Line Items]
Total revenues	7,281	7,557	20,094	20,122
Operating Businesses [Member] | Pilot Travel Centers ("PTC") [Member]
Segment Reporting Information [Line Items]
Total revenues	13,166		37,428
Operating Businesses [Member] | Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Total revenues	19,174	19,000	56,565	57,193
Operating Businesses [Member] | McLane [Member]
Segment Reporting Information [Line Items]
Total revenues	13,477	13,569	39,419	39,346
Operating Businesses [Member] | Service and Retailing [Member]
Segment Reporting Information [Line Items]
Total revenues	9,946	9,567	30,018	28,299
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 11	$ 81	$ (87)	$ 33