Income Taxes	6 Months Ended
Jun. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes ProAssurance estimates its annual effective tax rate at the end of each quarterly reporting period which is used to record the provision for income taxes in the interim financial statements. The provision for income taxes is different from that which would be obtained by applying the statutory Federal income tax rate to income before taxes primarily because a portion of ProAssurance’s investment income is tax-exempt, because ProAssurance utilizes tax credit benefits transferred from tax credit partnership investments, and in 2013, because ProAssurance recognized a non-taxable gain related to an acquisition. The IRS has concluded an examination of the 2009 and 2010 returns and has issued a Notice of Proposed Adjustment (NOPA) for these years which would increase our current tax liability by approximately $130 million. ProAssurance has begun the IRS appeals process and is unable to reliably predict the timing of the final resolution or the ultimate outcome. The contested issues affect only the timing of when certain expense items are deductible for tax purposes and resolution of the NOPA would have no effect on our recorded tax expense, exclusive of interest found to be due on past-due taxes, if any. At June 30, 2013, ProAssurance had a receivable for federal income taxes of $48 million, which was carried as a part of Other Assets. ProAssurance had a payable for federal income taxes of $20 million at December 31, 2012, which was carried as a part of Other Liabilities. Except for the 2006 tax year, the statutes of limitation are closed for all years prior to 2009. The statutes for the 2006, 2009 and 2010 tax years have been extended until September 30, 2014.

Income Taxes

6 Months Ended

Jun. 30, 2013

ProAssurance estimates its annual effective tax rate at the end of each quarterly reporting period which is used to record the provision for income taxes in the interim financial statements. The provision for income taxes is different from that which would be obtained by applying the statutory Federal income tax rate to income before taxes primarily because a portion of ProAssurance’s investment income is tax-exempt, because ProAssurance utilizes tax credit benefits transferred from tax credit partnership investments, and in 2013, because ProAssurance recognized a non-taxable gain related to an acquisition.

The IRS has concluded an examination of the 2009 and 2010 returns and has issued a Notice of Proposed Adjustment (NOPA) for these years which would increase our current tax liability by approximately $130 million. ProAssurance has begun the IRS appeals process and is unable to reliably predict the timing of the final resolution or the ultimate outcome. The contested issues affect only the timing of when certain expense items are deductible for tax purposes and resolution of the NOPA would have no effect on our recorded tax expense, exclusive of interest found to be due on past-due taxes, if any.

At June 30, 2013, ProAssurance had a receivable for federal income taxes of $48 million, which was carried as a part of Other Assets. ProAssurance had a payable for federal income taxes of $20 million at December 31, 2012, which was carried as a part of Other Liabilities.

Except for the 2006 tax year, the statutes of limitation are closed for all years prior to 2009. The statutes for the 2006, 2009 and 2010 tax years have been extended until September 30, 2014.