Restructuring	12 Months Ended
Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring Aon Hewitt Restructuring Plan On October 14, 2010, the Company announced a global restructuring plan ("Aon Hewitt Plan") in connection with the acquisition of Hewitt Associates, Inc. The Aon Hewitt Plan was intended to streamline operations across the combined Aon Hewitt organization. The Company incurred all remaining costs for the Aon Hewitt Plan and the plan was closed in the fourth quarter of 2013. For the year ended December 31, 2014, no charges were taken under the Aon Hewitt Plan. For year ended December 31, 2013, $174 million of restructuring expenses were charged, of which $94 million and $80 million were in the Risk Solutions segment and HR Solutions segment, respectively. For the year ended December 31, 2012, $98 million of restructuring expenses were charged, of which $32 million and $66 million were in the Risk Solutions segment and HR Solutions segment, respectively. As of December 31, 2013, the remaining liabilities for the Company's restructuring plans were $166 million. During the year ended December 31, 2014, the Company made cash payments of $83 million, resulting in remaining restructuring liabilities of $76 million as of December 31, 2014. The remaining $7 million reduction is due to fluctuation in foreign exchange rates. The Company's unpaid restructuring liabilities are included in both Accounts payable and accrued liabilities and Other non-current liabilities in the Consolidated Statements of Financial Position.

Restructuring

12 Months Ended

Dec. 31, 2014

Restructuring and Related Activities [Abstract]

Aon Hewitt Restructuring Plan

On October 14, 2010, the Company announced a global restructuring plan ("Aon Hewitt Plan") in connection with the acquisition of Hewitt Associates, Inc. The Aon Hewitt Plan was intended to streamline operations across the combined Aon Hewitt organization. The Company incurred all remaining costs for the Aon Hewitt Plan and the plan was closed in the fourth quarter of 2013. For the year ended December 31, 2014, no charges were taken under the Aon Hewitt Plan. For year ended December 31, 2013, $174 million of restructuring expenses were charged, of which $94 million and $80 million were in the Risk Solutions segment and HR Solutions segment, respectively. For the year ended December 31, 2012, $98 million of restructuring expenses were charged, of which $32 million and $66 million were in the Risk Solutions segment and HR Solutions segment, respectively.

As of December 31, 2013, the remaining liabilities for the Company's restructuring plans were $166 million. During the year ended December 31, 2014, the Company made cash payments of $83 million, resulting in remaining restructuring liabilities of $76 million as of December 31, 2014. The remaining $7 million reduction is due to fluctuation in foreign exchange rates. The Company's unpaid restructuring liabilities are included in both Accounts payable and accrued liabilities and Other non-current liabilities in the Consolidated Statements of Financial Position.