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Income Taxes - Narrative (Details) - USD ($) $ in Millions |  | 3 Months Ended | 12 Months Ended | 71 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 01, 2023 | Dec. 31, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2023 | Jan. 01, 2023
Income Taxes [Line Items] |  |  |  |  |  |  |
Income tax expense (benefit) |  |  | $ (93) | $ 11 | $ 58 |  |
Deferred tax assets, operating loss carryforwards, domestic |  | $ 23 | 23 |  |  |  |
Deferred tax assets, operating loss carryforwards, foreign |  | 7 | 7 |  |  |  |
Net operating loss |  | 30 | 30 | 37 |  |  |
Less: Valuation allowance |  | 0 | $ 0 | 5 | 24 |  | $ 2
Decrease in valuation allowance |  |  |  | 19 | 0 |  |
Realization assessment period |  |  | 3 years |  |  |  |
Unrecognized tax benefits |  | 0 | $ 0 | 0 | 0 |  |
Income tax penalties and interest accrued |  | 0 | 0 | $ 0 | $ 0 |  |
Foreign Tax Credit Provision Adjustment |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Decrease in valuation allowance |  |  | 3 |  |  |  |
Foreign Tax Credit Change In Realization |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Decrease in valuation allowance |  |  | 2 |  |  |  |
CIFG Holding Inc. |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Operating loss carryforwards |  | 189 | $ 189 |  |  |  |
U.K. |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Corporate tax rate | 25.00% |  | 23.50% |  |  | 19.00% |
France |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Corporate tax rate |  |  | 25.00% | 25.00% | 27.50% |  |
U.S. |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Corporate tax rate |  |  | 21.00% | 21.00% | 21.00% |  |
Foreign Tax Authority |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Income tax expense (benefit) |  | $ (189) |  |  |  |  |
Foreign Tax Authority | Minimum |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Income tax benefit, period of recognition |  | 10 years |  |  |  |  |
Foreign Tax Authority | Maximum |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |
Income tax benefit, period of recognition |  | 15 years |  |  |  |  |

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