XML 59 R48.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Acquisitions and Dispositions of Businesses - Completed Dispositions (Details) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 USD ($) disposition | Sep. 30, 2021 USD ($) disposition | Sep. 30, 2022 USD ($) disposition | Sep. 30, 2021 USD ($) disposition
Business Combination and Asset Acquisition [Abstract] |  |  |  |
Number of dispositions | disposition | 0 | 2 | 3 | 3
Gain from sales of businesses | $ | $ 6 | $ 1 | $ 53 | $ 2

X
- Definition Represents the number of entities disposed of by the reporting entity. + References No definition available. + Details
Name: | aon_NumberOfDispositions
Namespace Prefix: | aon_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_BusinessCombinationAndAssetAcquisitionAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1B -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=109239629&loc=SL4582445-111684 + Details
Name: | us-gaap_GainLossOnSaleOfBusiness
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration