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Notes payable and other borrowings - Narrative (Detail) € in Millions, £ in Millions, $ in Millions, ¥ in Billions	1 Months Ended	12 Months Ended
	Jan. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2025 JPY (¥)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2025 JPY (¥)	Dec. 31, 2025 EUR (€)	Dec. 31, 2025 GBP (£)
Berkshire Hathaway Inc. (Parent) [Member]
Debt Instrument [Line Items]
Repayments of borrowings		$ 1,919		$ 1,854	$ 4,310
Notes payable and other borrowings		22,662		21,091
Gain (loss) attributable to changes in foreign currency exchange rates		(501)		1,376	371
Berkshire Hathaway Inc. (Parent) [Member] \| Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings						¥ 2,343.0	€ 4,850	£ 1,750
Line of Credit and Commercial Paper Facilities [Member] \| Subsidiaries [Member]
Debt Instrument [Line Items]
Unused and available lines of credit		10,700
Line of Credit and Commercial Paper Facilities [Member] \| Subsidiaries [Member] \| Berkshire Hathaway Energy and Subsidiaries [Member]
Debt Instrument [Line Items]
Unused and available lines of credit		9,300
Insurance and Other [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings		45,763		44,885
Insurance and Other [Member] \| Berkshire Hathaway Inc. (Parent) [Member] \| Subsidiaries Excluding Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Guarantee obligation		$ 1,700
Insurance and Other [Member] \| Subsidiaries [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage		5.10%				5.10%	5.10%	5.10%
Notes payable and other borrowings		$ 3,518		4,564
Short-term debt		$ 1,321		1,315
Insurance and Other [Member] \| Subsidiaries [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year		2026	2026
Insurance and Other [Member] \| Subsidiaries [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year		2051	2051
Insurance and Other [Member] \| Senior Notes [Member] \| Berkshire Hathaway Inc. (Parent) [Member]
Debt Instrument [Line Items]
Repayments of borrowings		$ 1,900
Insurance and Other [Member] \| Senior Notes [Member] \| Berkshire Hathaway Inc. (Parent) [Member] \| Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Gain (loss) attributable to changes in foreign currency exchange rates		(840)		1,500	$ 217
Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2028 to 2055 [Member] \| Berkshire Hathaway Inc. (Parent) [Member]
Debt Instrument [Line Items]
Principal amount of debt issued		$ 3,000	¥ 451.6
Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2028 to 2055 [Member] \| Berkshire Hathaway Inc. (Parent) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Interest rate during period		1.35%	1.35%
Debt maturity year		2028	2028
Insurance and Other [Member] \| Senior Notes [Member] \| Senior Notes and Term Loan Due 2028 to 2055 [Member] \| Berkshire Hathaway Inc. (Parent) [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Interest rate during period		3.12%	3.12%
Debt maturity year		2055	2055
Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings		$ 83,318		79,877
Railroad, Utilities and Energy [Member] \| Subsidiaries [Member] \| Berkshire Hathaway Energy and Subsidiaries [Member]
Debt Instrument [Line Items]
Short-term debt		$ 1,997		1,123
Railroad, Utilities and Energy [Member] \| Subsidiaries [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage		4.80%				4.80%	4.80%	4.80%
Notes payable and other borrowings		$ 45,798		$ 42,150
Railroad, Utilities and Energy [Member] \| Subsidiaries [Member] \| Minimum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year		2026	2026
Railroad, Utilities and Energy [Member] \| Subsidiaries [Member] \| Maximum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year		2064	2064
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Repayments of borrowings		$ 2,700
Principal amount of debt issued		$ 4,300
Weighted average interest rate, percentage		6.20%				6.20%	6.20%	6.20%
Short-term debt		$ 875
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| BNSF [Member]
Debt Instrument [Line Items]
Repayments of borrowings		$ 1,300
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Minimum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year		2035	2035
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Maximum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year		2056	2056
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Subsequent Event [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Principal amount of debt issued	$ 1,500
Weighted average interest rate, percentage	6.40%
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Subsequent Event [Member] \| Minimum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year	2029
Railroad, Utilities and Energy [Member] \| Term Debt [Member] \| Subsidiaries [Member] \| Subsequent Event [Member] \| Maximum [Member] \| Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Debt maturity year	2056
Railroad, Utilities and Energy [Member] \| Senior Unsecured Debenture [Member] \| Subsidiaries [Member] \| BNSF [Member]
Debt Instrument [Line Items]
Principal amount of debt issued		$ 1,850
Debt maturity year		2056	2056
Weighted average interest rate, percentage		5.65%				5.65%	5.65%	5.65%