Sales of Receivables and Servicing Rights - Additional Information (Details) - USD ($) $ in Billions	9 Months Ended	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Transfers and Servicing [Abstract]
Servicing Asset, Fair Value, Change in Fair Value, Other, Statement of Income or Comprehensive Income [Extensible Enumeration]	Fees and Commissions, Mortgage Banking and Servicing	Fees and Commissions, Mortgage Banking and Servicing
Servicing of residential mortgage loans for other investors	$ 95.8		$ 100.8
Weighted-average coupon of the MSR portfolio (as a percent)	3.78%		3.72%

Indicates line item in statement of income or comprehensive income that includes increase (decrease) in fair value classified as other for contract to service financial asset under which benefit of servicing is expected to more than adequately compensate servicer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481229/860-50-50-3

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Period Type:	duration