v2.4.0.6

Goodwill and Other Intangible Assets (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2011
Goodwill and Other Intangible Assets |
Schedule of changes in the net carrying amount of goodwill by operating segment |
|  | Risk Solutions |  | HR Solutions |  | Total |
--- | --- | --- | --- | --- | --- | --- | ---
Balance as of January 1, 2010 |  |  | 5,693 |  |  | 385 |  |  | 6,078 |
Goodwill related to Hewitt acquisition |  |  | — |  |  | 2,715 |  |  | 2,715 |
Goodwill related to other acquisitions |  |  | 50 |  |  | 9 |  |  | 59 |
Goodwill related to disposals |  |  | (2 | ) |  | — |  |  | (2 | )
Foreign currency revaluation |  |  | (192 | ) |  | (11 | ) |  | (203 | )
Balance as of December 31, 2010 |  | $ | 5,549 |  | $ | 3,098 |  | $ | 8,647 |
Goodwill related to acquisitions |  |  | 73 |  |  | 4 |  |  | 77 |
Goodwill related to disposals |  |  | (2 | ) |  | — |  |  | (2 | )
Goodwill related to Hewitt acquisition |  |  | — |  |  | 50 |  |  | 50 |
Goodwill related to other prior year acquisitions |  |  | — |  |  | 1 |  |  | 1 |
Transfers |  |  | (83 | ) |  | 83 |  |  | — |
Foreign currency revaluation |  |  | 20 |  |  | (23 | ) |  | (3 | )
Balance as of December 31, 2011 |  | $ | 5,557 |  | $ | 3,213 |  | $ | 8,770 |
Schedule of other intangible assets by asset class |
|  | As of December 31 |
--- | --- | --- | ---
|  | 2011 |  | 2010 |
|  | Gross Carrying Amount |  | Accumulated Amortization |  | Net Carrying Amount |  | Gross Carrying Amount |  | Accumulated Amortization |  | Net Carrying Amount |
Intangible assets with indefinite lives: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Trademarks |  | $ | 1,024 |  | $ | — |  | $ | 1,024 |  | $ | 1,024 |  | $ | — |  | $ | 1,024 |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | — |
Intangible assets with finite lives: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | — |
Trademarks |  |  | 4 |  |  | 1 |  |  | 3 |  |  | 3 |  |  | — |  |  | 3 |
Customer related and contract based |  |  | 2,608 |  |  | 615 |  |  | 1,993 |  |  | 2,605 |  |  | 344 |  |  | 2,261 |
Marketing, technology and other |  |  | 606 |  |  | 350 |  |  | 256 |  |  | 606 |  |  | 283 |  |  | 323 |
|  | $ | 4,242 |  | $ | 966 |  | $ | 3,276 |  | $ | 4,238 |  | $ | 627 |  | $ | 3,611 |
Schedule of estimated future amortization expense on intangible assets |
|  | HR Solutions |  | Risk Solutions |  | Total |
--- | --- | --- | --- | --- | --- | --- | ---
2012 |  | $ | 294 |  | $ | 117 |  | $ | 411 |
2013 |  |  | 275 |  |  | 109 |  |  | 384 |
2014 |  |  | 239 |  |  | 95 |  |  | 334 |
2015 |  |  | 208 |  |  | 81 |  |  | 289 |
2016 |  |  | 174 |  |  | 71 |  |  | 245 |
Thereafter |  |  | 468 |  |  | 121 |  |  | 589 |
|  | $ | 1,658 |  | $ | 594 |  | $ | 2,252 |

X
- Definition Tabular disclosure of the class of other intangible assets, which includes finite and indefinite-lived intangible assets. + References No definition available. + Details
Name: | aon_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTableTextBlock
Namespace Prefix: | aon_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. + References No definition available. + Details
Name: | us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of goodwill by reportable segment and in total. Disclosure details may include, but are not limited to, the carrying amount of goodwill, goodwill acquired during the year, goodwill impairment losses recognized, goodwill written-off due to the sale of a business unit, goodwill not yet allocated, and any other changes to goodwill. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6905597&loc=d3e13854-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6905597&loc=d3e13816-109267 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 45 -Subparagraph c -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 142 -Paragraph 45 -Subparagraph e -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 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 47 -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
Name: | us-gaap_ScheduleOfGoodwillTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration