Derivatives - Schedule of Notional Amounts and The Gross Fair Values of RPAs Sold and Purchased Outstanding (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Derivative [Line Items]
Derivative assets - Fair value	$ 408,429	$ 523,133
Derivative liabilities - Fair value	382,202	545,885
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional Amount	23,480,807	22,375,840
Derivative assets - Fair value	366,014	517,486
Derivative liabilities - Fair value	381,192	510,674
Credit contracts | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional Amount	210,205	168,999
Derivative assets - Fair value	17	1
Derivative liabilities - Fair value	58	12
Credit contracts | Derivatives not designated as hedging instruments | RPAs — protection sold
Derivative [Line Items]
Notional Amount	146,126	133,174
Derivative assets - Fair value	0	0
Derivative liabilities - Fair value	$ 58	$ 12
Weighted average remaining maturity of outstanding RPAs	2 years 3 months 18 days	1 year 7 months 6 days
Credit contracts | Derivatives not designated as hedging instruments | RPAs — protection purchased
Derivative [Line Items]
Notional Amount	$ 64,079	$ 35,825
Derivative assets - Fair value	17	1
Derivative liabilities - Fair value	$ 0	$ 0