XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.20.2

Revenue from Contracts with Customers - Contract Assets Rollforward (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Capitalized Cost To Fulfill Customer Contracts |  |  |  |
Change in Capitalized Contract Costs |  |  |  |
Balance at beginning of period | $ 193 | $ 216 | $ 335 | $ 329
Additions | 291 | 326 | 883 | 1,008
Amortization | (266) | (299) | (995) | (1,095)
Impairment | 0 | 0 | 0 | 0
Foreign currency translation and other | 2 | (4) | (3) | (3)
Balance at end of period | 220 | 239 | 220 | 239
Capitalized Cost To Obtain Customer Contracts |  |  |  |
Change in Capitalized Contract Costs |  |  |  |
Balance at beginning of period | 172 | 161 | 171 | 156
Additions | 15 | 14 | 43 | 40
Amortization | (12) | (11) | (35) | (33)
Impairment | 0 | 0 | 0 | 0
Foreign currency translation and other | 1 | (1) | (3) | 0
Balance at end of period | $ 176 | $ 163 | $ 176 | $ 163

X
- Definition Capitalized Contract Cost, Additions + References No definition available. + Details
Name: | aon_CapitalizedContractCostAdditions
Namespace Prefix: | aon_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Capitalized Contract Cost, Foreign Currency And Other Adjustments Net + References No definition available. + Details
Name: | aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet
Namespace Prefix: | aon_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Change In Capitalized Contract Costs [Roll Forward] + References No definition available. + Details
Name: | aon_ChangeInCapitalizedContractCostsRollForward
Namespace Prefix: | aon_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 340 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054 + Details
Name: | us-gaap_CapitalizedContractCostAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 340 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054 + Details
Name: | us-gaap_CapitalizedContractCostImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 340 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054 + Details
Name: | us-gaap_CapitalizedContractCostNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_CapitalizedContractCostAxis=aon_CapitalizedCostToFulfillCustomerContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CapitalizedContractCostAxis=aon_CapitalizedCostToObtainCustomerContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |