Mortgage Servicing Rights - Summary of Key Unobservable Inputs Used in Determining the Fair Value (Details) - MSR - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Minimum
Servicing Assets at Fair Value [Line Items]
Discount rates (as a percent)	10.00%	10.00%
Annual prepayment speeds (as a percent)	5.40%	5.30%
Cost of servicing	$ 74	$ 74
Maximum
Servicing Assets at Fair Value [Line Items]
Discount rates (as a percent)	16.00%	16.00%
Annual prepayment speeds (as a percent)	21.50%	21.90%
Cost of servicing	$ 111	$ 111
Weighted Average
Servicing Assets at Fair Value [Line Items]
Discount rates (as a percent)	11.10%	11.10%
Annual prepayment speeds (as a percent)	8.20%	9.60%
Cost of servicing	$ 85	$ 84