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v3.25.3

Cover - shares | 9 Months Ended |
--- | --- | ---
Sep. 30, 2025 | Oct. 30, 2025
Entity Information [Line Items] |  |
Document Type | 10-Q |
Document Quarterly Report | true |
Document Period End Date | Sep. 30, 2025 |
Document Transition Report | false |
Entity File Number | 1-7933 |
Entity Registrant Name | Aon plc |
Entity Incorporation, State or Country Code | L2 |
Entity Tax Identification Number | 98-1539969 |
Entity Address, Address Line One | 15 George's Quay |
Entity Address, City or Town | Dublin 2 |
Entity Address, Country | IE |
Entity Address, Postal Zip Code | D02 VR98 |
Country Region | 353 |
City Area Code | 1 |
Local Phone Number | 266 6000 |
Entity Current Reporting Status | Yes |
Entity Interactive Data Current | Yes |
Entity Filer Category | Large Accelerated Filer |
Entity Small Business | false |
Entity Emerging Growth Company | false |
Entity Shell Company | false |
Entity Common Stock, Shares Outstanding |  | 214,935,265
Entity Central Index Key | 0000315293 |
Amendment Flag | false |
Document Fiscal Year Focus | 2025 |
Document Fiscal Period Focus | Q3 |
Current Fiscal Year End Date | --12-31 |
Class A Ordinary Shares $0.01 nominal value |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Class A Ordinary Shares $0.01 nominal value |
Trading Symbol | AON |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 3.875% Senior Notes due 2025 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 3.875% Senior Notes due 2025 |
Trading Symbol | AON25 |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 2.875% Senior Notes due 2026 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 2.875% Senior Notes due 2026 |
Trading Symbol | AON26 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.850% Senior Notes due 2027 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.850% Senior Notes due 2027 |
Trading Symbol | AON27 |
Security Exchange Name | NYSE |
Guarantees of Aon North America, Inc.’s 5.125% Senior Notes due 2027 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon North America, Inc.’s 5.125% Senior Notes due 2027 |
Trading Symbol | AON27B |
Security Exchange Name | NYSE |
Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029 |
Trading Symbol | AON29 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.050% Senior Notes due 2031 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.050% Senior Notes due 2031 |
Trading Symbol | AON31 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.600% Senior Notes due 2031 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.600% Senior Notes due 2031 |
Trading Symbol | AON31A |
Security Exchange Name | NYSE |
Guarantees of Aon North America, Inc.’s 5.300% Senior Notes due 2031 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon North America, Inc.’s 5.300% Senior Notes due 2031 |
Trading Symbol | AON31B |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.000% Senior Notes due 2032 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.000% Senior Notes due 2032 |
Trading Symbol | AON32 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.350% Senior Notes due 2033 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.350% Senior Notes due 2033 |
Trading Symbol | AON33 |
Security Exchange Name | NYSE |
Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034 |
Trading Symbol | AON34 |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 4.250% Senior Notes due 2042 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 4.250% Senior Notes due 2042 |
Trading Symbol | AON42 |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 4.450% Senior Notes due 2043 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 4.450% Senior Notes due 2043 |
Trading Symbol | AON43 |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 4.600% Senior Notes due 2044 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 4.600% Senior Notes due 2044 |
Trading Symbol | AON44 |
Security Exchange Name | NYSE |
Guarantees of Aon plc’s 4.750% Senior Notes due 2045 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon plc’s 4.750% Senior Notes due 2045 |
Trading Symbol | AON45 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.900% Senior Notes due 2051 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.900% Senior Notes due 2051 |
Trading Symbol | AON51 |
Security Exchange Name | NYSE |
Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.900% Senior Notes due 2052 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.900% Senior Notes due 2052 |
Trading Symbol | AON52 |
Security Exchange Name | NYSE |
Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054 |  |
Entity Information [Line Items] |  |
Title of 12(b) Security | Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054 |
Trading Symbol | AON54 |
Security Exchange Name | NYSE |

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