Other Assets - Mortgage Servicing Rights - Quantitative Assumptions Used for MSRs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Minimum
Quantitative assumptions used in determining lower of cost or fair value of MSRs
Conditional prepayment rate (as a percent)	7.02%	6.87%
Life in years (of the MSR)	4 years 5 months 1 day	4 years 3 months 18 days
Weighted-average coupon rate (as a percent)	3.68%	3.57%
Discount rate (as a percent)	10.35%	10.40%
Maximum
Quantitative assumptions used in determining lower of cost or fair value of MSRs
Conditional prepayment rate (as a percent)	13.34%	11.53%
Life in years (of the MSR)	7 years 29 days	7 years 2 months 19 days
Weighted-average coupon rate (as a percent)	5.69%	5.81%
Discount rate (as a percent)	10.93%	10.60%
Weighted Average
Quantitative assumptions used in determining lower of cost or fair value of MSRs
Conditional prepayment rate (as a percent)	7.22%	7.04%
Life in years (of the MSR)	6 years 11 months 8 days	7 years 1 month 2 days
Weighted-average coupon rate (as a percent)	3.79%	3.73%
Discount rate (as a percent)	10.39%	10.52%