Fair Value of Assets and Liabilities (Quantitative Info for Level 3 Inputs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Corporate securities	$ 824,270	$ 148,179
Market risk benefits assets	2,367,243	1,393,237	[1]
Other assets	2,078,938	1,331,427	[1]
Market risk benefit liabilities	5,144,401	5,521,601	[1]
Fair Value, Measurements, Recurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market risk benefits assets	2,367,243	1,393,237
Other assets	224,019	141,041
Market risk benefit liabilities	5,144,401	5,521,601
Policyholders’ account balances	7,689,929	3,502,096
Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Funds held under reinsurance agreements	$ 10,000,000
Level 3 | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Policyholder Age	50 years
Level 3 | Minimum   | Market risk benefit liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortality rate	0.00%
Level 3 | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Policyholder Age	90 years
Level 3 | Fair Value, Measurements, Recurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market risk benefits assets	$ 2,367,243	1,393,237
Other assets	224,019	141,041
Market risk benefit liabilities	5,144,401	5,521,601
Policyholders’ account balances	$ 7,689,929	$ 3,502,096
Level 3 | Internal | Minimum   | Discounted cash flow | Market risk benefit liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	1.00%	1.00%
Spread over SOFR	0.41%	0.50%
Utilization rate	38.00%	38.00%
Withdrawal rate (greater than maximum range)	81.00%	77.00%
Mortality rate	0.00%	0.00%
Equity volatility curve	15.00%	18.00%
Level 3 | Internal | Minimum   | Discounted cash flow | Policyholders' account balances
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	1.00%	1.00%
Spread over SOFR	0.41%	0.22%
Mortality rate	0.00%	0.00%
Equity volatility curve	6.00%	6.00%
Option budget	(1.00%)	(2.00%)
Level 3 | Internal | Minimum   | Discounted cash flow | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate	6.98%	9.77%
Level 3 | Internal | Minimum   | Discounted cash flow | Commercial mortgage-backed securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidity premium	0.60%
Level 3 | Internal | Minimum   | Discounted cash flow | Market risk benefit assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	1.00%	1.00%
Spread over SOFR	0.41%	0.50%
Utilization rate	38.00%	38.00%
Withdrawal rate (greater than maximum range)	81.00%	77.00%
Mortality rate	0.00%	0.00%
Equity volatility curve	15.00%	18.00%
Level 3 | Internal | Minimum   | Discounted cash flow | Other assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	1.00%
Spread over SOFR	0.41%
Mortality rate	0.00%
Equity volatility curve	6.00%
Option budget	(1.00%)
Level 3 | Internal | Minimum   | Market comparables | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
EBITDA multiples		2.2
Level 3 | Internal | Minimum   | Liquidation | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidation value	63.62%
Level 3 | Internal | Maximum | Discounted cash flow | Market risk benefit liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	20.00%	20.00%
Spread over SOFR	1.91%	2.20%
Utilization rate	95.00%	95.00%
Withdrawal rate (greater than maximum range)	100.00%	100.00%
Mortality rate	15.00%	15.00%
Equity volatility curve	25.00%	26.00%
Level 3 | Internal | Maximum | Discounted cash flow | Policyholders' account balances
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	80.00%	80.00%
Spread over SOFR	1.85%	2.26%
Mortality rate	23.00%	23.00%
Equity volatility curve	25.00%	30.00%
Option budget	7.00%	6.00%
Level 3 | Internal | Maximum | Discounted cash flow | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate	20.00%	20.00%
Level 3 | Internal | Maximum | Discounted cash flow | Commercial mortgage-backed securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidity premium	0.75%
Level 3 | Internal | Maximum | Discounted cash flow | Market risk benefit assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	20.00%	20.00%
Spread over SOFR	1.91%	2.20%
Utilization rate	95.00%	95.00%
Withdrawal rate (greater than maximum range)	100.00%	100.00%
Mortality rate	15.00%	15.00%
Equity volatility curve	25.00%	26.00%
Level 3 | Internal | Maximum | Discounted cash flow | Other assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	80.00%
Spread over SOFR	1.85%
Mortality rate	23.00%
Equity volatility curve	25.00%
Option budget	7.00%
Level 3 | Internal | Maximum | Market comparables | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
EBITDA multiples		23.5
Level 3 | Internal | Maximum | Liquidation | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidation value	63.62%
Level 3 | Internal | Weighted Average | Discounted cash flow | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate	9.73%	16.53%
Level 3 | Internal | Weighted Average | Discounted cash flow | Commercial mortgage-backed securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidity premium	0.71%
Level 3 | Internal | Weighted Average | Market comparables | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
EBITDA multiples		8.1
Level 3 | Internal | Weighted Average | Liquidation | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liquidation value	63.62%
Level 3 | Internal | Fair Value, Measurements, Recurring | Market risk benefit liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market risk benefit liabilities	$ 5,144,401	$ 5,521,601
Level 3 | Internal | Fair Value, Measurements, Recurring | Policyholders' account balances
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Policyholders’ account balances	7,689,929	3,502,096
Level 3 | Internal | Fair Value, Measurements, Recurring | Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Corporate securities	81,635	408,494
Level 3 | Internal | Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Commercial mortgage-backed securities	78,115
Level 3 | Internal | Fair Value, Measurements, Recurring | Market risk benefit assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market risk benefits assets	2,367,243	$ 1,393,237
Level 3 | Internal | Fair Value, Measurements, Recurring | Other assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Other assets	$ 224,019

[1] Prior period amounts reflect the implementation of Accounting Standard Update ("ASU") 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.