Significant accounting policies and practices - Summary of effects of adopting ASU 2018-12 on selected financial statement line items (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2021	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2018-12 [Member]	Accounting Standards Update 2018-12 [Member]
Life, annuity and health insurance benefits		$ 27,295	$ 20,213	$ 19,753
Income taxes, principally deferred	$ 72,403		93,009	77,368
Accumulated other comprehensive income	(9,994)		(3,763)	(5,052)
Retained earnings	443,949		607,350	511,127
Berkshire Hathaway shareholders’ equity	436,736		561,273	473,424
Insurance And Other [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Life, annuity and health insurance benefits	28,836		20,213	19,753
Other policyholder liabilities	$ 10,367		$ 11,545	$ 11,370
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income taxes, principally deferred					$ 74,098
Accumulated other comprehensive income					(4,243)
Retained earnings					444,626
Berkshire Hathaway shareholders’ equity					443,164
Previously Reported [Member] | Insurance And Other [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Life, annuity and health insurance benefits					21,616
Other policyholder liabilities					8,670
Revision of Prior Period, Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income taxes, principally deferred					(1,695)
Accumulated other comprehensive income					(5,751)
Retained earnings					(677)
Berkshire Hathaway shareholders’ equity					(6,428)
Revision of Prior Period, Adjustment [Member] | Insurance And Other [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Life, annuity and health insurance benefits					7,220
Other policyholder liabilities					$ 1,697