Fair Values of Financial Instruments (Carrying Amounts and Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets
Derivative instruments	$ 1,207,288	$ 431,727	[1]
Other investments	2,277,822	1,817,085	[1]
Coinsurance deposits	14,582,728	13,254,956	[1]
Market risk benefits	479,694	229,871	[1]
Liabilities
Policy benefit reserves	303,200	318,677
Market risk benefits	3,146,554	2,455,492	[1]
Other policy funds - FHLB	0
Carrying Amount
Assets
Fixed maturity securities, available for sale	34,780,482	39,804,617
Mortgage loans on real estate	7,537,594	6,949,027
Real estate investments	1,334,247	1,056,063
Limited partnerships and limited liability companies	506,685	684,835
Derivative instruments	1,207,288	431,727
Other investments	2,277,822	1,817,085
Cash and cash equivalents	9,772,586	1,919,669
Coinsurance deposits	14,582,728	13,254,956
Market risk benefits	479,694	229,871
Liabilities
Policy benefit reserves	60,549,922	58,419,911
Market risk benefits	3,146,554	2,455,492
Single premium immediate annuity (SPIA) benefit reserves	188,301	212,119
Other policy funds - FHLB	0	300,000
Notes and loan payable	785,443	792,073
Subordinated debentures	79,107	78,753
Fair Value
Assets
Fixed maturity securities, available for sale	34,780,482	39,804,617
Mortgage loans on real estate	7,047,993	6,502,463
Real estate investments	1,336,247	1,056,063
Limited partnerships and limited liability companies	506,685	684,835
Derivative instruments	1,207,288	431,727
Other investments	2,277,822	1,817,085
Cash and cash equivalents	9,772,586	1,919,669
Coinsurance deposits	13,570,942	12,640,797
Market risk benefits	479,694	229,871
Liabilities
Policy benefit reserves	56,366,631	55,572,896
Market risk benefits	3,146,554	2,455,492
Single premium immediate annuity (SPIA) benefit reserves	196,720	221,130
Other policy funds - FHLB	0	300,000
Notes and loan payable	770,570	774,220
Subordinated debentures	$ 86,254	$ 87,293

[1] Certain prior period amounts have been recast. See Note 1 - Significant Accounting Policies for more information.