Basis of Presentation

6 Months Ended

Jun. 30, 2011

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”) and include all normal recurring adjustments which Aon Corporation (“Aon” or the “Company”) considers necessary to present fairly the Company’s Condensed Consolidated Financial Statements for all periods presented.  The consolidated financial statements include the accounts of Aon and its wholly and majority-owned subsidiaries and variable interest entities (“VIEs”) for which Aon is considered to be the primary beneficiary.  The consolidated financial statements exclude special-purpose entities (“SPEs”) considered VIEs for which Aon is not the primary beneficiary. All material intercompany accounts and transactions have been eliminated.

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, 2010.  The presentation of certain amounts in the financial statements and related notes for prior periods has been changed to conform to the presentation in the Annual Report on Form 10-K for the year ended December 31, 2010.  The results for the three and six months ended June 30, 2011 are not necessarily indicative of operating results that may be expected for the full year ending December 31, 2011.

Use of Estimates

The preparation of the accompanying unaudited 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 reserves and expenses. These estimates and assumptions are based on management’s best estimates and judgments.  Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances.  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 precision, actual results could differ significantly from these estimates.  Changes in estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.