Income taxes - Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Currently payable (receivable)	$ 500	$ (643)
Deferred	76,959	63,199
Other income tax liabilities	485	570
Income taxes, principally deferred	$ 77,944	$ 63,126

Sum of the carrying amounts as of the balance sheet date for a) payments made in advance for income taxes, which will be charged against earnings, b) income taxes previously overpaid to tax authorities representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes, c) the net cumulative amount for all deferred taxes arising from temporary differences between accounting income in accordance with generally accepted accounting principles and tax-basis income, and d) unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.

No definition available.

Name:	brka_IncomeTaxesPrincipallyDeferred
Namespace Prefix:	brka_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant