Mortgage Servicing Rights - Summary of Adverse Changes to Weighted-Average Assumptions on the Fair Value of Servicing Rights (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
Sensitivity Analysis, Actual [Abstract]
Option adjusted spread (percent)	5.40%
Constant prepayment rate (as a percent)	7.90%
Weighted average cost to service per loan	$ 69,000,000
Sensitivity Analysis, Adverse Change, Tranche 1 [Abstract]
Option adjusted spread (percent)	(20,000,000)
Constant prepayment rate (as a percent)	(37,000,000)
Weighted average cost to service per loan	(10,000,000)
Sensitivity Analysis, Adverse Change, Tranche 2 [Abstract]
Option adjusted spread (percent)	(39,000,000)
Constant prepayment rate (as a percent)	(71,000,000)
Weighted average cost to service per loan	$ (21,000,000)