Fair Value of Assets and Liabilities (Financial Instruments where Carrying Amounts and Fair Values May Differ) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets:
Policy loans	$ 499,612	$ 1,327,485
Cash and cash equivalents	2,400,480	918,931
Accrued investment income	191,602	160,027
Reinsurance recoverables	35,398,214	38,598,767
Receivables from parent and affiliates	207,961	278,131
Liabilities:
Cash collateral for loaned securities	194,927	3,004
Fair Value
Assets:
Commercial mortgage and other loans	4,046,382	2,883,710
Policy loans	499,612	1,327,485
Short-term Investments	172,840	37,000
Cash and cash equivalents	816,226	482,299
Accrued investment income	191,602	160,027
Reinsurance recoverables	24,534	29,931
Receivables from parent and affiliates	60,065	116,086
Other assets	619,851	568,981
Total assets	6,431,112	5,605,519
Liabilities:
Policyholders’ account balances - investment contracts	4,064,014	3,947,337
Cash collateral for loaned securities	194,927	3,004
Long-term debt to affiliates	295,260	319,225
Payables to parent and affiliates	56,103	31,775
Other liabilities	1,015,584	898,879
Total liabilities	5,625,888	5,200,220
Carrying Amount
Assets:
Commercial mortgage and other loans	4,385,543	2,832,560
Policy loans	499,612	1,327,485
Short-term Investments	172,840	37,000
Cash and cash equivalents	816,226	482,299
Accrued investment income	191,602	160,027
Reinsurance recoverables	26,975	28,883
Receivables from parent and affiliates	60,065	116,086
Other assets	619,851	568,981
Total assets	6,772,714	5,553,321
Liabilities:
Policyholders’ account balances - investment contracts	4,086,739	3,941,822
Cash collateral for loaned securities	194,927	3,004
Long-term debt to affiliates	313,521	320,362
Payables to parent and affiliates	56,103	31,775
Other liabilities	1,015,584	898,879
Total liabilities	5,666,874	5,195,842
Level 1 | Fair Value
Assets:
Commercial mortgage and other loans	0	0
Policy loans	0	0
Short-term Investments	172,840	37,000
Cash and cash equivalents	816,226	297,299
Accrued investment income	0	0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	0	0
Other assets	0	0
Total assets	989,066	334,299
Liabilities:
Policyholders’ account balances - investment contracts	0	0
Cash collateral for loaned securities	0	0
Long-term debt to affiliates	0	0
Payables to parent and affiliates	0	0
Other liabilities	0	0
Total liabilities	0	0
Level 2 | Fair Value
Assets:
Commercial mortgage and other loans	0	0
Policy loans	0	0
Short-term Investments	0	0
Cash and cash equivalents	0	185,000
Accrued investment income	191,602	160,027
Reinsurance recoverables	0	0
Receivables from parent and affiliates	60,065	116,086
Other assets	42,104	134,598
Total assets	293,771	595,711
Liabilities:
Policyholders’ account balances - investment contracts	1,250,349	1,356,850
Cash collateral for loaned securities	194,927	3,004
Long-term debt to affiliates	295,260	319,225
Payables to parent and affiliates	56,103	31,775
Other liabilities	982,334	864,788
Total liabilities	2,778,973	2,575,642
Level 3 | Fair Value
Assets:
Commercial mortgage and other loans	4,046,382	2,883,710
Policy loans	499,612	1,327,485
Short-term Investments	0	0
Cash and cash equivalents	0	0
Accrued investment income	0	0
Reinsurance recoverables	24,534	29,931
Receivables from parent and affiliates	0	0
Other assets	577,747	434,383
Total assets	5,148,275	4,675,509
Liabilities:
Policyholders’ account balances - investment contracts	2,813,665	2,590,487
Cash collateral for loaned securities	0	0
Long-term debt to affiliates	0	0
Payables to parent and affiliates	0	0
Other liabilities	33,250	34,091
Total liabilities	$ 2,846,915	$ 2,624,578