Business segment data - Earnings before income taxes (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Investment gains (losses)	$ 1,876	$ 34,758
Non-controlled businesses	493	688
Earnings before income taxes	15,706	44,752
Operating Businesses [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	12,486	9,540
Operating Businesses [Member] \| Insurance Group [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	6,478	3,587
Investment income	3,152	2,385
Operating Businesses [Member] \| Insurance Group [Member] \| GEICO [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	1,928	703
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Primary Group [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	486	268
Operating Businesses [Member] \| Insurance Group [Member] \| Berkshire Hathaway Reinsurance Group [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	912	231
Operating Businesses [Member] \| BNSF [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	1,519	1,649
Operating Businesses [Member] \| Berkshire Hathaway Energy [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	432	223
Operating Businesses [Member] \| Pilot [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	70	136
Operating Businesses [Member] \| Manufacturing Businesses [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	2,914	2,611
Operating Businesses [Member] \| McLane [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	165	113
Operating Businesses [Member] \| Service and Retailing [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	908	1,221
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment gains (losses)	1,876	34,758
Interest expense, not allocated to segments	(96)	(114)
Non-controlled businesses	493	688
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Earnings Before Income Taxes of Operating Businesses	$ 947	$ (120)

Amount of realized and unrealized gain (loss) on investment.

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