XML 79 R51.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Share-Based Compensation Plans Share-based compensation expenses recognized (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2015 | Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Total share-based compensation expense | $ 90 us-gaap_AllocatedShareBasedCompensationExpense | $ 102 us-gaap_AllocatedShareBasedCompensationExpense
Restricted share units (RSUs) [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Total share-based compensation expense | 65 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_RestrictedStockUnitsRSUMember | 60 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_RestrictedStockUnitsRSUMember
Performance share awards (“PSAs”) [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Total share-based compensation expense | 21 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_PerformanceSharesMember | 39 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_PerformanceSharesMember
Share options [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Total share-based compensation expense | 0 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_EmployeeStockOptionMember | 0 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_EmployeeStockOptionMember
Employee share purchase plans [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Total share-based compensation expense | $ 4 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = aon_EmployeeStockPurchasePlanMember | $ 3 us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = aon_EmployeeStockPurchasePlanMember

X
- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_AwardTypeAxis=aon_EmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |