Income Taxes	9 Months Ended
Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes The effective tax rate on earnings before income taxes for the first nine months of 2019 was 19.6 percent, compared with 18.4 percent for the first nine months of 2018. The increase in the effective tax rate in the first nine months of 2019 from the first nine months of 2018 primarily reflects lower tax-exempt interest income arising from municipal bond securities, lower dividends received-deductions and higher state income taxes. Alleghany believes that, as of September 30, 2019, it had no material uncertain tax positions. Interest and penalties related to unrecognized tax expenses (benefits) are recognized in income tax expense, when applicable. There were no material liabilities for interest or penalties accrued as of September 30, 2019.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

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