Mortgage Servicing Rights - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Transfers and Servicing [Abstract]
Residential mortgage loans serviced for others including subserviced mortgages with no corresponding MSRs asset	$ 220,800		$ 220,800		$ 216,600
Gain (loss) on fair value changes of MSRs due to changes in valuation assumptions and derivatives used to economically hedge MSRs	(4)	$ 24	(2)	$ 21
Loan servicing and ancillary fees	$ 172	$ 176	$ 356	$ 344

Amount of contractually specified servicing fee, late fee, and ancillary fee recognized as income for servicing asset and servicing liability.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481229/860-50-50-2

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration