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v3.25.3

Accelerating Aon United Program - Schedule of Changes in the Company’s Liabilities for the Program (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Restructuring Reserve [Roll Forward] |  |  |  |
Charges | $ 32 | $ 69 | $ 236 | $ 320
Accelerating Aon United Program |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |
Liability balance as of December 31, 2024 |  |  | 114 |
Charges | 32 | $ 69 | 236 | $ 320
Cash payments |  |  | (234) |
Foreign currency translation and other |  |  | 5 |
Non-cash charges |  |  | (31) |
Liability balance as of September 30, 2025 | 90 |  | 90 |
Total costs incurred from inception to date | 760 |  | 760 |
Accelerating Aon United Program | Technology and other |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |
Liability balance as of December 31, 2024 |  |  | 17 |
Charges |  |  | 138 |
Cash payments |  |  | (124) |
Foreign currency translation and other |  |  | 0 |
Non-cash charges |  |  | (7) |
Liability balance as of September 30, 2025 | 24 |  | 24 |
Total costs incurred from inception to date | 278 |  | 278 |
Accelerating Aon United Program | Workforce optimization |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |
Liability balance as of December 31, 2024 |  |  | 97 |
Charges |  |  | 91 |
Cash payments |  |  | (110) |
Foreign currency translation and other |  |  | 5 |
Non-cash charges |  |  | (17) |
Liability balance as of September 30, 2025 | 66 |  | 66 |
Total costs incurred from inception to date | 391 |  | 391 |
Accelerating Aon United Program | Asset impairments |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |
Liability balance as of December 31, 2024 |  |  | 0 |
Charges |  |  | 7 |
Cash payments |  |  | 0 |
Foreign currency translation and other |  |  | 0 |
Non-cash charges |  |  | (7) |
Liability balance as of September 30, 2025 | 0 |  | 0 |
Total costs incurred from inception to date | $ 91 |  | $ 91 |

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