Mortgage Servicing Rights - Schedule of Changes in Servicing Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning balance	$ 25	$ 23	$ 18
Servicing rights originated	4	4	11
Servicing rights obtained in CIT Merger	0	3	0
Amortization	(4)	(6)	(9)
Valuation allowance benefit	0	1	3
Ending balance	$ 25	$ 25	$ 23

Servicing Asset at Amortized Cost, Acquired In Business Combination

No definition available.

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- Definition

The periodic amortization (in proportion to and over the period of estimated net servicing income or loss) of capitalized servicing rights, which contractually entitle the servicer to receive fees and ancillary revenues for performing billing, collection, disbursement and recordkeeping services in connection with a mortgage portfolio. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
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-Topic 230
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 860
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-Section 50
-Paragraph 4
-Subparagraph (a)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481229/860-50-50-4

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- Definition

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481229/860-50-50-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
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-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481260/860-50-45-1

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481260/860-50-45-2

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- Definition

Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481229/860-50-50-4

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481229/860-50-50-4

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