v2.4.0.6

Acquisitions and Dispositions (Details 2) (USD $) Share data in Millions, except Per Share data, unless otherwise specified |  |  | 1 Months Ended | 12 Months Ended |  |  |  | 1 Months Ended |  | 1 Months Ended | 3 Months Ended |  | 1 Months Ended |  | 1 Months Ended |
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Dec. 31, 2011 | Dec. 31, 2010 | Oct. 31, 2010 Cash Electing Consideration D | Oct. 31, 2010 Stock Electing Consideration D | Oct. 31, 2010 Hewitt Associates, Inc (Hewitt) Y | Dec. 31, 2011 Hewitt Associates, Inc (Hewitt) | Dec. 31, 2010 Hewitt Associates, Inc (Hewitt) | Oct. 02, 2010 Hewitt Associates, Inc (Hewitt) | Dec. 31, 2011 Hewitt Associates, Inc (Hewitt) HR Solutions | Dec. 31, 2010 Hewitt Associates, Inc (Hewitt) HR Solutions | Oct. 30, 2010 Hewitt Associates, Inc (Hewitt) Cash Electing Consideration | Oct. 02, 2010 Hewitt Associates, Inc (Hewitt) Cash Electing Consideration | Oct. 31, 2010 Hewitt Associates, Inc (Hewitt) Mixed Consideration and Stock Electing Consideration | Sep. 30, 2010 Hewitt Associates, Inc (Hewitt) Mixed Consideration and Stock Electing Consideration | Oct. 02, 2010 Hewitt Associates, Inc (Hewitt) Mixed Consideration and Stock Electing Consideration | Oct. 30, 2010 Hewitt Associates, Inc (Hewitt) Mixed Consideration Election | Oct. 02, 2010 Hewitt Associates, Inc (Hewitt) Mixed Consideration Election | Oct. 30, 2010 Hewitt Associates, Inc (Hewitt) Stock Electing Consideration | Oct. 02, 2010 Hewitt Associates, Inc (Hewitt) Stock Electing Consideration
Business Acquisition |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of aggregate consideration to be paid in cash and in number of shares each |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |
Par value of Hewitt Class A Common Stock per share (in dollars per share) |  |  |  |  |  |  |  | $ 0.01 |  |  |  |  |  |  |  |  |  |  |
Common stock, par value (in dollars per share) | $ 1 | $ 1 |  |  |  |  |  | $ 1.00 |  |  |  |  |  |  |  |  |  |  |
Consecutive trading days |  |  | 10 | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Closing volume-weighted average price of Aon's common stock (in dollars per share) |  |  |  |  |  |  |  |  |  |  | $ 39.0545 |  |  |  |  |  |  | $ 39.0545 |
Cash consideration |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Hewitt common shares outstanding electing consideration |  |  |  |  |  |  |  |  |  |  |  | 7.78 |  |  |  |  | 44.52 |  | 43.67
Cash consideration per common share outstanding (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  | $ 50.46 |  |  |  |  | $ 25.61 |  | $ 21.19
Cash paid in business acquisition |  |  |  |  |  |  |  | $ 2,458,000,000 |  |  |  | $ 393,000,000 |  |  |  |  | $ 1,140,000,000 |  | $ 925,000,000
Stock consideration |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Hewitt common shares outstanding electing consideration |  |  |  |  |  |  |  |  |  |  |  | 7.78 |  |  |  |  | 44.52 |  | 43.67
Exchange ratio of Aon shares issued to Hewitt shareholders (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 63.62% |  | 74.94%
Number of Aon common shares issued to finance Hewitt acquisition (in shares) |  |  |  |  | 61.05 |  |  |  |  |  |  |  |  | 61.05 |  | 28.32 |  | 32.73 |
Aon's closing common share price (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  | $ 39.28 |  |  |  |  |  |
Total fair value of stock consideration |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,398,000,000 |  |  |  |
Fair value of Hewitt stock options converted to options to acquire Aon common stock |  |  |  |  |  |  |  | 76,000,000 |  |  |  |  |  |  |  |  |  |  |
Total consideration transferred | 103,000,000 | 5,089,000,000 |  |  |  |  |  | 4,932,000,000 |  |  |  |  |  |  |  |  |  |  |
Acquisition, integration and financing expenses |  |  |  |  |  | 47,000,000 | 54,000,000 |  | 47,000,000 | 19,000,000 |  |  |  |  |  |  |  |  |
Acquisition, integration and financing cost recorded in Other General Expenses |  |  |  |  |  | 47,000,000 | 40,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Acquisition, integration and financing cost recorded in interest Expenses |  |  |  |  |  |  | 14,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Debt Financing of the Transaction |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Drawing under Term Loan Credit Facility |  |  |  |  |  |  |  | 1,000,000,000 |  |  |  |  |  |  |  |  |  |  |
Term of Term Loan Facility (in years) |  |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of Notes |  |  |  |  |  |  |  | $ 1,500,000,000 |  |  |  |  |  |  |  |  |  |  |
Options issued as consideration to former holders of Hewitt stock options (in options) |  |  |  |  | 4.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition This element represents the fair value of the stock options of the acquiree that were converted to stock options of the acquirer in relation to a business acquisition. + References No definition available. + Details
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- Definition This element represents the closing volume-weighted average common stock on NYSE for the period of the last ten consecutive trading days of the reporting period used for calculating consideration in the merger. + References No definition available. + Details
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- Definition This element represents the portion of aggregate merger consideration to be paid in cash and total number of shares of the entity as a condition in the Stock Electing Consideration. + References No definition available. + Details
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- Definition Amount of cash paid to acquire the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph f(1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition The acquisition-date fair value of the equity interests of the acquirer, including the number of instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph f(4) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 88-16 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 39 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 24 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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