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Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Balance at beginning of period | $ 30 | $ 31
Additions for tax positions related to prior years | 5 | 1
Reductions for tax positions of prior years | 0 | (2)
Expiration of statutes of limitations | (2) | (1)
Settlements | (2) | (5)
Balance at end of period | 31 | 30
CIT Group Inc. |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Effect of CIT Merger | 0 | 6
Liabilities for Unrecognized Tax Benefits |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Balance at beginning of period | 27 |
Additions for tax positions related to prior years | 4 |
Reductions for tax positions of prior years | 0 |
Expiration of statutes of limitations | (2) |
Settlements | (1) |
Balance at end of period | 28 | 27
Liabilities for Unrecognized Tax Benefits | CIT Group Inc. |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Effect of CIT Merger | 0 |
Interest / Penalties |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Balance at beginning of period | 3 |
Additions for tax positions related to prior years | 1 |
Reductions for tax positions of prior years | 0 |
Expiration of statutes of limitations | 0 |
Settlements | (1) |
Balance at end of period | 3 | $ 3
Interest / Penalties | CIT Group Inc. |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |
Effect of CIT Merger | $ 0 |

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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 10B -Publisher FASB -URI https://asc.fasb.org//1943274/2147482525/740-10-45-10B + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A + Details
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- Definition Amount of increase in unrecognized tax benefits resulting from acquisitions. + References No definition available. + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A + Details
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