Fair Value of Assets and Liabilities (Quantitative Info for Level 3 Inputs) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Corporate securities	$ 196,988	$ 148,179
Market Risk Benefit, Asset	1,427,488	1,393,237
Market risk benefit liabilities	5,621,681	5,521,601
Fair Value, Measurements, Recurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market Risk Benefit, Asset	1,427,488	1,393,237
Market risk benefit liabilities	5,621,681	5,521,601
Policyholders’ account balances	$ 4,129,043	3,502,096
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 Benefit, Asset	$ 1,427,488	1,393,237
Market risk benefit liabilities	5,621,681	5,521,601
Policyholders’ account balances	$ 4,129,043	$ 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	0.52%	0.50%
Utilization rate	38.00%	38.00%
Withdrawal rate (greater than maximum range)	77.00%	77.00%
Mortality rate	0.00%	0.00%
Equity volatility curve	18.00%	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	0.27%	0.17%
Mortality rate	0.00%	0.00%
Equity volatility curve	6.00%	6.00%
Option budget	(2.00%)	(2.00%)
Level 3 \| Internal \| Minimum \| Discounted cash flow \| Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate	5.67%	9.77%
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	0.52%	0.03%
Utilization rate	38.00%	39.00%
Withdrawal rate (greater than maximum range)	77.00%	77.00%
Mortality rate	0.00%	0.00%
Equity volatility curve	18.00%	16.00%
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	82.86%
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	2.20%	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	2.34%	1.93%
Mortality rate	23.00%	23.00%
Equity volatility curve	30.00%	30.00%
Option budget	6.00%	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 \| Market risk benefit assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Lapse rate	20.00%	20.00%
Spread over SOFR	2.20%	1.13%
Utilization rate	95.00%	96.00%
Withdrawal rate (greater than maximum range)	100.00%	100.00%
Mortality rate	15.00%	15.00%
Equity volatility curve	25.00%	25.00%
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	82.86%
Level 3 \| Internal \| Weighted Average \| Discounted cash flow \| Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate	8.01%	16.53%
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	82.86%
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	$ 5,621,681	$ 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	4,129,043	3,502,096
Level 3 \| Internal \| Fair Value, Measurements, Recurring \| Corporate securities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Corporate securities	429,741	408,494
Level 3 \| Internal \| Fair Value, Measurements, Recurring \| Market risk benefit assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Market Risk Benefit, Asset	$ 1,427,488	$ 1,393,237

Fair Value Inputs Discount Rates

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Market value of entity divided by earnings before interest, taxes, depreciation and amortization (EBITDA), used as an input to measure fair value.

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Fair Value Inputs Expected Volatility Rate

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Actuarially determined assumption around contract lapse rates used as in input in calculating fair value of future policy benefits (primarily embedded derivatives associated with living benefit features on annuity contracts.

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Liquidation value of asset or liability used as an input to a fair value calculation.

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Actuarially determined assumption around client mortality rates used as in input in calculating fair value of future policy benefits (primarily embedded derivatives associated with living benefit features on annuity contracts.

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Fair value inputs option budget.

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Fair Value Inputs, Policyholder Age

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Fair Value Inputs Spread Over Sofr

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Actuarially determined assumption around utilization rates used as in input in calculating fair value of future policy benefits (primarily embedded derivatives associated with living benefit features on annuity contracts.

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Actuarially determined assumption around withdrawal rates used as in input in calculating fair value of future policy benefits (primarily embedded derivatives associated with living benefit features on annuity contracts.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of asset position for contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk.

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Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 55
-Paragraph 29G
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Amount of liability position for contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk.

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Amount of investment in marketable security.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
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Amount due to policyholders for funds held that are returnable under the terms of insurance contracts, classified as other.

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