Business segment data - Earnings (loss) before income taxes (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Investment and derivative gains (losses)	$ 74,855	$ (67,899)	$ 78,542
Interest expense, not allocated to segments	(5,003)	(4,352)	(4,172)
Non-controlled businesses	1,973	1,863	886
Earnings (loss) before income taxes	120,166	(30,500)	111,861
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	43,637	34,775	32,466
Interest expense, not allocated to segments	(4,630)	(3,946)	(3,828)
Operating Businesses [Member] \| Insurance Group [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	18,494	7,702	6,760
Investment income	11,581	7,724	5,649
Operating Businesses [Member] \| Insurance Group [Member] \| GEICO [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	3,635	(1,880)	1,259
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	1,904	1,465	(755)
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	1,374	393	607
Operating Businesses [Member] \| Insurance Group [Member] \| Insurance Underwriting [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	6,913	(22)	1,111
Operating Businesses [Member] \| BNSF [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	6,614	7,708	7,861
Interest expense, not allocated to segments	(1,048)	(1,025)	(1,032)
Operating Businesses [Member] \| Berkshire Hathaway Energy ("BHE") [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	940	3,146	3,293
Interest expense, not allocated to segments	(2,283)	(2,140)	(2,054)
Operating Businesses [Member] \| PTC [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	968
Interest expense, not allocated to segments	(414)
Operating Businesses [Member] \| Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	11,445	11,177	9,841
Interest expense, not allocated to segments	(784)	(739)	(704)
Operating Businesses [Member] \| McLane [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	455	271	230
Operating Businesses [Member] \| Service and Retailing [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	4,721	4,771	4,481
Interest expense, not allocated to segments	(101)	(42)	(38)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment and derivative gains (losses)	74,855	(67,899)	78,542
Interest expense, not allocated to segments	(426)	(420)	(455)
Non-controlled businesses	1,973	1,863	886
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Earnings (loss) before income taxes from operating businesses	127	1,181	422
Interest expense, not allocated to segments	$ 53	$ 14	$ 111

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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