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Income Taxes - Narrative (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | Jan. 03, 2022 | Dec. 31, 2021
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Income Tax Disclosure [Abstract] |  |  |  |
Amount of unrecognized deferred tax liability, reinvested earnings of foreign subsidiaries | $ 18 |  |  |
Reinvested earnings of foreign subsidiaries | 670 |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Net operating loss carry forwards | 118 | $ 358 |  |
Domestic tax credits | 21 | 176 |  |
Deferred tax assets, valuation allowance | 28 | 70 |  |
Unrecognized tax benefits, income tax penalties and interest accrued | 3 |  |  |
Unrecognized tax benefits | 31 | 30 |  | $ 31
Decrease in unrecognized tax benefits is reasonably possible | 10 |  |  |
CIT Group Inc. |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Deferred tax liabilities |  |  | $ 300 |
Domestic Tax Authority | Internal Revenue Service (IRS) |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Domestic tax credits | 16 |  |  |
State and Local Jurisdiction |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Net operating loss carry forwards | 98 |  |  |
Operating loss carryforwards | 1,730 |  |  |
Domestic tax credits | 5 |  |  |
Deferred tax assets, valuation allowance | 28 |  |  |
Foreign Tax Authority |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |
Net operating loss carry forwards | 20 |  |  |
Operating loss carryforwards | $ 85 |  |  |
Deferred tax assets, valuation allowance |  | $ 3 |  |

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- Definition Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15 + Details
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