Notes payable and other borrowings (Detail) € in Millions, £ in Millions, $ in Millions, ¥ in Billions	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2022 EUR (€)	Sep. 30, 2022 GBP (£)	Sep. 30, 2022 JPY (¥)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Notes payable and other borrowings		€ 8,150	£ 1,750	¥ 914
Insurance and Other [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 41,535				$ 39,272
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | U.S. Dollar Denominated [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 6,227				6,820
Weighted average interest rate, percentage	3.30%	3.30%	3.30%	3.30%
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | U.S. Dollar Denominated [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2023
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | U.S. Dollar Denominated [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2047
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Euro Denominated [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 6,722				7,792
Weighted average interest rate, percentage	1.00%	1.00%	1.00%	1.00%
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Euro Denominated [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2023
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Euro Denominated [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2041
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Japanese Yen Denominated [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 6,289				6,797
Weighted average interest rate, percentage	0.60%	0.60%	0.60%	0.60%
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Japanese Yen Denominated [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2023
Insurance and Other [Member] | Berkshire Hathaway Inc. (Parent) [Member] | Japanese Yen Denominated [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2060
Insurance and Other [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 4,328				4,438
Short-term debt	$ 374				342
Weighted average interest rate, percentage	4.10%	4.10%	4.10%	4.10%
Short-term borrowings, weighted average interest rate	4.70%	4.70%	4.70%	4.70%
Insurance and Other [Member] | Subsidiaries [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2022
Insurance and Other [Member] | Subsidiaries [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2045
Insurance and Other [Member] | Subsidiaries [Member] | U.S. Dollar Denominated [Member] | Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 14,456				10,758
Weighted average interest rate, percentage	3.60%	3.60%	3.60%	3.60%
Insurance and Other [Member] | Subsidiaries [Member] | U.S. Dollar Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2027
Insurance and Other [Member] | Subsidiaries [Member] | U.S. Dollar Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2052
Insurance and Other [Member] | Subsidiaries [Member] | Euro Denominated [Member] | Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 1,219
Weighted average interest rate, percentage	1.80%	1.80%	1.80%	1.80%
Insurance and Other [Member] | Subsidiaries [Member] | Euro Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2030
Insurance and Other [Member] | Subsidiaries [Member] | Euro Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2034
Insurance and Other [Member] | Subsidiaries [Member] | Great Britain Pound Denominated [Member] | Berkshire Hathaway Finance Corporation [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 1,920				2,325
Weighted average interest rate, percentage	2.50%	2.50%	2.50%	2.50%
Insurance and Other [Member] | Subsidiaries [Member] | Great Britain Pound Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2039
Insurance and Other [Member] | Subsidiaries [Member] | Great Britain Pound Denominated [Member] | Berkshire Hathaway Finance Corporation [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2059
Railroad, Utilities and Energy [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 74,961				74,990
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy [Member]
Debt Instrument [Line Items]
Weighted average interest rate, percentage	4.30%	4.30%	4.30%	4.30%
Senior unsecured debt	$ 13,992				13,003
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2023
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2053
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy Subsidiaries [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 36,226				36,759
Weighted average interest rate, percentage	4.20%	4.20%	4.20%	4.20%
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy Subsidiaries [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2022
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy Subsidiaries [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2064
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Berkshire Hathaway Energy and Subsidiaries [Member]
Debt Instrument [Line Items]
Short-term debt	$ 1,441				2,009
Short-term borrowings, weighted average interest rate	4.20%	4.20%	4.20%	4.20%
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Burlington Northern Santa Fe ("BNSF") and subsidiaries [Member]
Debt Instrument [Line Items]
Notes payable and other borrowings	$ 23,302				$ 23,219
Weighted average interest rate, percentage	4.50%	4.50%	4.50%	4.50%
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Burlington Northern Santa Fe ("BNSF") and subsidiaries [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt maturity year	2022
Railroad, Utilities and Energy [Member] | Subsidiaries [Member] | Burlington Northern Santa Fe ("BNSF") and subsidiaries [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt maturity year	2097