Derivatives (Tables)

12 Months Ended

Dec. 31, 2024

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location

The following table presents the Company’s Ultra-Long Treasury Futures derivatives, primary underlying risk exposure, gross notional amount, and estimated fair value of these derivatives:

		Dec 31, 2024						Dec 31, 2023
(Dollars in Millions)				Estimated Fair Value						Estimated Fair Value
Derivative Instrument	Primary Underlying Risk Exposure	Gross Notional Amount		Assets		Liabilities		Gross Notional Amount		Assets		Liabilities
Derivatives Designated as Hedging Instruments:
Treasury Futures	Interest Rate Risk	$	75.0	$	—	$	(3.7)	$	—	$	—	$	—
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Treasury Futures	Interest Rate Risk	$	—	$	—	$	—	$	149.7	$	14.7	$	—

Derivative Instruments, Gain (Loss)

The below table reflects the amounts of Gains (Losses) deferred into AOCI before taxes, net changes in amounts in AOCI associated with current hedging transactions, and amounts subsequently reclassified into Net Income (Loss) through Net Investment Income for Ultra-Long Treasury Futures qualifying as cash flow hedges for the years ended December 31, 2024 and 2023:

	Year Ended
(Dollars in Millions)	Dec 31, 2024		Dec 31, 2023
Beginning of Year	$	—	$	(0.4)
Gains (Losses) Deferred in AOCI	(4.4)		—
Net Change in AOCI with Current Period Hedging Transaction	(3.7)		—
Gains (Losses) Reclassified into Income	1.8		0.4
Net Comprehensive Gains (Losses) from Cash Flow Hedges	$	(6.3)	$	—