Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Gross Notional	$ 196,977,180	$ 187,608,681
Fair Value Assets	7,685,050	7,086,534
Fair Value Liabilities	(18,654,072)	(12,573,983)
Derivatives Designated as Hedge Accounting Instruments:
Derivative [Line Items]
Gross Notional	1,936,568	889,896
Fair Value Assets	233,812	37,314
Fair Value Liabilities	(10,778)	(6,900)
Derivatives Designated as Hedge Accounting Instruments: \| Interest Rate Swaps
Derivative [Line Items]
Gross Notional	3,225	3,344
Fair Value Assets	0	55
Fair Value Liabilities	(316)	0
Derivatives Designated as Hedge Accounting Instruments: \| Foreign Currency Swaps
Derivative [Line Items]
Gross Notional	1,933,343	886,552
Fair Value Assets	233,812	37,259
Fair Value Liabilities	(10,462)	(6,900)
Derivatives Not Qualifying as Hedge Accounting Instruments:
Derivative [Line Items]
Gross Notional	195,040,612	186,718,785
Fair Value Assets	7,451,238	7,049,220
Fair Value Liabilities	(18,643,294)	(12,567,083)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Swaps
Derivative [Line Items]
Gross Notional	138,419,110	130,358,860
Fair Value Assets	6,757,890	5,698,740
Fair Value Liabilities	(17,092,749)	(10,348,130)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Future
Derivative [Line Items]
Gross Notional	2,425,500	4,109,300
Fair Value Assets	3,267	2,876
Fair Value Liabilities	(201)	(2,709)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Foreign Currency Forwards
Derivative [Line Items]
Gross Notional	364,946	119,653
Fair Value Assets	590	842
Fair Value Liabilities	(10,423)	(1,063)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Credit Default Swaps
Derivative [Line Items]
Gross Notional	47,450	306,900
Fair Value Assets	346	24,789
Fair Value Liabilities	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Foreign Currency Swaps
Derivative [Line Items]
Gross Notional	2,289,170	2,139,523
Fair Value Assets	194,412	68,477
Fair Value Liabilities	(14,624)	(23,251)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Equity Options
Derivative [Line Items]
Gross Notional	25,187,516	19,461,881
Fair Value Assets	239,003	902,050
Fair Value Liabilities	(1,112,196)	(1,535,272)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| interest rate forward
Derivative [Line Items]
Gross Notional	1,104,000	195,000
Fair Value Assets	11,265	3,760
Fair Value Liabilities	(12,359)	(991)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Option
Derivative [Line Items]
Gross Notional	8,368,000	9,883,000
Fair Value Assets	123,168	280,323
Fair Value Liabilities	(225,125)	(173,863)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Total Return Swap
Derivative [Line Items]
Gross Notional	15,958,130	15,129,666
Fair Value Assets	120,341	66,627
Fair Value Liabilities	(175,104)	(475,209)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Equity Futures
Derivative [Line Items]
Gross Notional	876,790	5,015,002
Fair Value Assets	956	736
Fair Value Liabilities	$ (513)	$ (6,595)

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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