Mortgage Servicing Rights - Summary of Key Unobservable Inputs Used in Determining the Fair Value (Details) - MSR - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Minimum
Servicing Assets at Fair Value [Line Items]
Discount rates (as a percent)	9.50%	10.00%
Annual prepayment speeds (as a percent)	4.50%	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)	23.30%	21.90%
Cost of servicing	$ 119	$ 111
Weighted Average
Servicing Assets at Fair Value [Line Items]
Discount rates (as a percent)	11.00%	11.10%
Annual prepayment speeds (as a percent)	9.80%	9.60%
Cost of servicing	$ 83	$ 84