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Employee Benefits - Narrative (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | May 07, 2014
Other retirement plans |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Benefit obligation | $ 8,000,000 |  |  |
ICON Development Solutions Limited pension plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
44561 | 3.80% |  |  |
ICON Development Solutions Limited pension plan | Secured Loans and Multi Asset Credit |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Percentage of investments (in percent) | 20.00% |  |  |
44561 | 3.00% | 3.00% |  |
ICON Development Solutions Limited pension plan | Corporate Bonds (including 50% high yield bonds) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Percentage of investments (in percent) | 18.00% |  |  |
44561 | 2.80% | 2.80% |  |
ICON Development Solutions Limited pension plan | High yield bonds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Percentage of investments (in percent) | 19.00% |  |  |
ICON Development Solutions Limited pension plan | Equities |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Percentage of investments (in percent) | 24.00% |  |  |
44561 | 5.50% | 5.20% |  |
United States |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Participant's contributions percentage of annual compensation (in percent) | 4.50% |  |  |
Defined contribution plan, cost | $ 23,700,000 | $ 17,000,000 | $ 16,500,000 |
United Kingdom | ICON Development Solutions Limited pension plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Benefit obligation | 41,813,000 | $ 43,988,000 | $ 37,036,000 |
Net loss that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year | 200,000 |  |  |
Net prior service cost for defined benefit pension plan that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year | $ 0 |  |  |
Pension plan period | 26 years |  |  |
44561 | 3.40% | 4.00% | 2.10% |
Contribution to pension fund in the year ending December 31, 2021 | $ 100,000 |  |  |
Retirement period used as a basis to estimate expected cash flows | 10 years |  |  |
Switzerland | Aptiv Solutions pension plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Benefit obligation | $ 7,643,000 | $ 8,620,000 | $ 7,047,000 |
Switzerland | Aptiv Solutions pension plan | Aptiv Solutions |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Percentage of share capital acquired (in percent) |  |  |  | 100.00%

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