Income Taxes	3 Months Ended
Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes The Coronavirus Aid, Relief and Economic Security Act (the "CARES Act") was signed into law on March 27, 2020. Among other provisions, the CARES Act delayed certain employer payroll tax remittance deadlines and created or expanded certain income tax credits and loss carryback provisions and, as a result, Alleghany recorded a $6.9 million tax benefit as of March 31, 2020. The effective tax rate on earnings before income taxes for the first three months of 2020 was 22.4 percent compared with 19.5 percent for the first three months of 2019. The effective tax rate in the first three months of 2020 was calculated based on actual results through March 31, 2020 because management was not able to reliably estimate the annual effective tax rate in light of the significant losses incurred. The increase in the effective tax rate in the first quarter of 2020 from the first quarter of 2019 primarily reflects the impact of the CARES Act. Alleghany believes that, as of March 31, 2020, 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 March 31, 2020.

Income Taxes

3 Months Ended

Mar. 31, 2020

6. Income Taxes

The Coronavirus Aid, Relief and Economic Security Act (the "CARES Act") was signed into law on March 27, 2020. Among other provisions, the CARES Act delayed certain employer payroll tax remittance deadlines and created or expanded certain income tax credits and loss carryback provisions and, as a result, Alleghany recorded a $6.9 million tax benefit as of March 31, 2020.

The effective tax rate on earnings before income taxes for the first three months of 2020 was 22.4 percent compared with 19.5 percent for the first three months of 2019. The effective tax rate in the first three months of 2020 was calculated based on actual results through March 31, 2020 because management was not able to reliably estimate the annual effective tax rate in light of the significant losses incurred. The increase in the effective tax rate in the first quarter of 2020 from the first quarter of 2019 primarily reflects the impact of the CARES Act.

Alleghany believes that, as of March 31, 2020, 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 March 31, 2020.