Basis of Presentation

3 Months Ended

Mar. 31, 2012

Basis of Presentation

Basis of Presentation

1.  Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). The Condensed Consolidated Financial Statements include the accounts of Aon plc and all controlled subsidiaries (“Aon” or the “Company”). All material intercompany accounts and transactions have been eliminated. The Condensed Consolidated Financial Statements include, in the opinion of management, all adjustments (consisting of normal recurring adjustments and reclassifications) necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows for all periods presented.

Certain information and footnote disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2011. The results for the three months ended March 31, 2012 are not necessarily indicative of operating results that may be expected for the full year ending December 31, 2012.

Company Redomestication

On April 2, 2012, the Company completed the reorganization of the corporate structure of the group of companies controlled by its predecessor, Aon Corporation, as holding company of the Aon group, pursuant to which Aon Corporation merged with one of its indirect, wholly-owned subsidiaries and Aon plc became the publicly-held parent company of the Aon group. This transaction is referred to as the Redomestication. In the Redomestication, each issued and outstanding share of Aon Corporation common stock held by stockholders of Aon Corporation was converted into the right to receive one Class A Ordinary Share, nominal value $0.01 per share, of Aon plc. Likewise, equity incentive and compensation plans were assumed by Aon plc and amended to provide that those plans will now provide for the award and issuance of Aon plc Class A Ordinary Shares on a one-for-one basis. Shares of treasury stock of Aon Corporation were cancelled in the Redomestication. Any references to “Aon”, “the Company”, “us”, or “we,” or any similar references relating to periods before the Redomestication shall be construed as references to Aon Corporation, being the previous parent company of the Aon group.

Reclassification

Certain amounts in prior year’s Condensed Consolidated Financial Statements and related notes have been reclassified to conform to the 2012 presentation. In prior periods, remeasurement gains and losses from foreign currency transactions and related derivative instruments were recognized in Other general expenses in the Condensed Consolidated Statements of Income. These gains and losses are now included in Other income in the Condensed Consolidated Statements of Income and are disclosed in Note 4 to these Condensed Consolidated Financial Statements. The Company believes this provides greater clarity into the income generated from operations.

Use of Estimates

The preparation of the accompanying Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions are based on management’s best estimates and judgments, which management believes to be reasonable based on facts and circumstances. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, and foreign currency movements have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with definitive precision, actual results could differ significantly from these estimates. Future changes in estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.