Derivative Instruments (Financial Statement Classification and Impact of Derivatives Used in Qualifying and Non-qualifying Hedge Relationships) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 4,906,067	$ (246,742)	$ 6,139,403	$ (4,397,341)
Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	2,085	4,581	10,643	13,509
Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	5,161	(14,094)	10,627	(6,730)
Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	32,718	(45,498)	58,009	22,964
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	3,547	(194)	7,789	4,373
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	2,085	4,581	10,643	13,509
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	5,160	(13,989)	10,662	(6,694)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	32,718	(45,498)	58,009	22,964
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	3,547	(194)	7,789	4,373
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	2,085	4,581	10,643	13,509
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	5,160	(13,989)	10,662	(6,694)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	32,718	(45,498)	58,009	22,964
Derivatives Not Qualifying as Hedge Accounting Instruments: | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	4,902,520	(246,548)	6,131,614	(4,401,714)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1	(105)	(35)	(36)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(62,751)	(995,815)	(1,852,373)	5,974,212
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,649	(837)	1,803	250
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(9,413)	(17,813)	816	12,270
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1	(105)	(35)	(36)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Risk Contract | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,631	(344)	10,991	(5,872)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Risk Contract | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Risk Contract | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Risk Contract | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(18,433)	(2,116,755)	(1,798,400)	(1,931,846)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivative | Net Realized Investments Gain Loss
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	4,989,837	2,885,016	9,768,777	(8,450,728)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivative | Net investment income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivative | Other Income
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivative | Accumulated Other Comprehensive Income (Loss)
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 0	$ 0	$ 0	$ 0