Business segment data - Earnings before income taxes (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Investment and derivative contract gains (losses)	$ 34,758	$ (1,978)
Equity method investments	688	339
Earnings (loss) before income taxes	44,752	6,957
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	9,540	8,139
Operating Businesses [Member] \| Insurance Group [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	3,587	1,576
Operating Businesses [Member] \| Insurance Group [Member] \| Interest, Dividend and Other Investment Income [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	2,385	1,361
Operating Businesses [Member] \| Insurance Group [Member] \| GEICO [Member] \| Insurance Premiums Earned [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	703	(178)
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Primary Group [Member] \| Insurance Premiums Earned [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	268	92
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Reinsurance Group [Member] \| Insurance Premiums Earned [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	231	301
Operating Businesses [Member] \| BNSF [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	1,649	1,809
Operating Businesses [Member] \| Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	223	713
Operating Businesses [Member] \| Pilot [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	136
Operating Businesses [Member] \| Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	2,611	2,824
Operating Businesses [Member] \| McLane [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	113	82
Operating Businesses [Member] \| Service and Retailing [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	1,221	1,135
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment and derivative contract gains (losses)	34,758	(1,978)
Interest expense, not allocated to segments	(114)	(104)
Equity method investments	688	339
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes from operating businesses	$ (120)	$ 561

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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