Basis of Presentation

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. The Consolidated Financial Statements include the accounts of Aon plc and all of its controlled subsidiaries (“Aon” or the “Company”). Intercompany accounts and transactions have been eliminated. The 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.

On April 1, 2020, a scheme of arrangement under English law was completed pursuant to which the Class A ordinary shares of Aon plc, a public limited company incorporated under the laws of England and Wales and the publicly traded parent company of Aon Global Limited, were cancelled and the holders thereof received, on a one-for-one basis, Class A ordinary shares of Aon plc, an Irish public limited company formerly known as Aon Limited (“Aon plc”), as described in the proxy statement filed with the SEC on December 20, 2019 (the “Ireland Reorganization”). Aon plc is a tax resident of Ireland. References in this report to “Aon,” the “Company,” “we,” “us,” or “our” for time periods prior to April 1, 2020 refer to Aon Global Limited. References in the Financial Statements to “Aon,” the “Company,” “we,” “us,” or “our” for time periods on or after April 1, 2020, refer to Aon plc.

Use of Estimates

The preparation of the accompanying 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, the disclosures of contingent assets and liabilities at the date of the Consolidated 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. Management believes its estimates to be reasonable given the current facts available. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, foreign currency exchange rate movements, and, recently, impacts from the COVID-19 pandemic 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 would, if applicable, be reflected in the Consolidated Financial Statements in future periods.