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Claims, Lawsuits, and Other Contingencies - Legal Narrative (Details) £ in Millions, $ in Millions, $ in Millions |  | 1 Months Ended |
--- | --- | --- | ---
Oct. 03, 2017 USD ($) | Oct. 03, 2017 NZD ($) | Dec. 31, 2022 plaintiff | Apr. 30, 2021 USD ($) plaintiff | Apr. 30, 2021 GBP (£) plaintiff | Aug. 31, 2020 USD ($) plaintiff | Nov. 30, 2019 USD ($) defendant | Nov. 30, 2018 USD ($) | Apr. 27, 2018 USD ($)
Pending Litigation | Aon Hewitt Investment Consulting, Inc. |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |
Investment losses suffered by plaintiff |  |  |  |  |  |  |  |  | $ 200.0
Pending Litigation | Fatal Plain Crash In November2016 |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |
Value of damages sought |  |  |  | $ 35.0 | £ 29 | $ 844.0 |  | $ 16.0 |
Loss contingency, number of defendants | defendant |  |  |  |  |  |  | 3 |  |
Damages sought option 1 |  |  |  |  |  |  | $ 300.0 |  |
Damages sought option 2 |  |  |  |  |  |  | 50.0 |  |
Damages sought option 3 |  |  |  |  |  |  | $ 25.0 |  |
Loss contingency, number of plaintiffs | plaintiff |  |  | 43 | 16 | 16 | 43 |  |  |
Settled Litigation | Christchurch City Council |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |
Value of damages sought | $ 202.0 | $ 320 |  |  |  |  |  |  |

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