Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2012
Basis of Presentation
Basis of Accounting	Basis of Presentation - FirstMerit Corporation (“the Parent Company”) is a bank holding company whose principal asset is the common stock of its wholly-owned subsidiary, FirstMerit Bank, N. A. (the “Bank”). The Parent Company’s other subsidiaries include Citizens Savings Corporation of Stark County, FirstMerit Capital Trust I, FirstMerit Community Development Corporation, FirstMerit Risk Management, Inc., and FMT, Inc. All significant intercompany balances and transactions have been eliminated in consolidation. The accounting and reporting policies of FirstMerit Corporation and its subsidiaries (the “Corporation”) conform to generally accepted accounting principles in the United States of America (“U.S. GAAP”) and to general practices within the financial services industry. The consolidated balance sheet at December 31, 2011 has been derived from the audited consolidated financial statements at that date. The accompanying unaudited interim financial statements reflect all adjustments (consisting only of normally recurring adjustments) that are, in the opinion of FirstMerit Corporation’s Management (“Management”), necessary for a fair statement of the results for the interim periods presented. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been omitted in accordance with the rules of the Securities and Exchange Commission (“SEC”). The unaudited consolidated financial statements of the Corporation as of March 31, 2012 and 2011 are not necessarily indicative of the results that may be achieved for the full fiscal year or for any future period. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2011 (the “2011 Form 10-K”). Certain reclassifications of prior year’s amounts have been made to conform to the current year presentation. Such reclassifications had no effect on net earnings or equity.

Basis of Presentation - FirstMerit Corporation (“the Parent Company”) is a bank holding company whose principal asset is the common stock of its wholly-owned subsidiary, FirstMerit Bank, N. A. (the “Bank”). The Parent Company’s other subsidiaries include Citizens Savings Corporation of Stark County, FirstMerit Capital Trust I, FirstMerit Community Development Corporation, FirstMerit Risk Management, Inc., and FMT, Inc. All significant intercompany balances and transactions have been eliminated in consolidation.

The accounting and reporting policies of FirstMerit Corporation and its subsidiaries (the “Corporation”) conform to generally accepted accounting principles in the United States of America (“U.S. GAAP”) and to general practices within the financial services industry.

The consolidated balance sheet at December 31, 2011 has been derived from the audited consolidated financial statements at that date. The accompanying unaudited interim financial statements reflect all adjustments (consisting only of normally recurring adjustments) that are, in the opinion of FirstMerit Corporation’s Management (“Management”), necessary for a fair statement of the results for the interim periods presented. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been omitted in accordance with the rules of the Securities and Exchange Commission (“SEC”). The unaudited consolidated financial statements of the Corporation as of March 31, 2012 and 2011 are not necessarily indicative of the results that may be achieved for the full fiscal year or for any future period. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2011 (the “2011 Form 10-K”). Certain reclassifications of prior year’s amounts have been made to conform to the current year presentation. Such reclassifications had no effect on net earnings or equity.