Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Gross Notional	$ 187,608,681	$ 5,030,826
Fair Value Assets	7,086,534	397,546
Fair Value Liabilities	(12,573,983)	(265,826)
Derivatives Designated as Hedge Accounting Instruments:
Derivative [Line Items]
Gross Notional	889,896	864,560
Fair Value Assets	37,314	27,539
Fair Value Liabilities	(6,900)	(49,316)
Derivatives Designated as Hedge Accounting Instruments: \| Interest Rate Swaps
Derivative [Line Items]
Gross Notional	3,344	3,486
Fair Value Assets	55	203
Fair Value Liabilities	0	0
Derivatives Designated as Hedge Accounting Instruments: \| Foreign Currency Swaps
Derivative [Line Items]
Gross Notional	886,552	861,074
Fair Value Assets	37,259	27,336
Fair Value Liabilities	(6,900)	(49,316)
Derivatives Not Qualifying as Hedge Accounting Instruments:
Derivative [Line Items]
Gross Notional	186,718,785	4,166,266
Fair Value Assets	7,049,220	370,007
Fair Value Liabilities	(12,567,083)	(216,510)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Swaps
Derivative [Line Items]
Gross Notional	130,358,860	663,050
Fair Value Assets	5,698,740	57,024
Fair Value Liabilities	(10,348,130)	(11,117)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Future
Derivative [Line Items]
Gross Notional	4,109,300	57,700
Fair Value Assets	2,876	198
Fair Value Liabilities	(2,709)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Foreign Currency Forwards
Derivative [Line Items]
Gross Notional	119,653	55,292
Fair Value Assets	842	5
Fair Value Liabilities	(1,063)	(1,322)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Credit Default Swaps
Derivative [Line Items]
Gross Notional	306,900	2,313
Fair Value Assets	24,789	0
Fair Value Liabilities	0	(18)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Foreign Currency Swaps
Derivative [Line Items]
Gross Notional	2,139,523	143,011
Fair Value Assets	68,477	6,584
Fair Value Liabilities	(23,251)	(7,286)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Equity Options
Derivative [Line Items]
Gross Notional	19,461,881	3,244,900
Fair Value Assets	902,050	306,196
Fair Value Liabilities	(1,535,272)	(196,767)
Derivatives Not Qualifying as Hedge Accounting Instruments: \| interest rate forward
Derivative [Line Items]
Gross Notional	195,000	0
Fair Value Assets	3,760	0
Fair Value Liabilities	(991)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Interest Rate Option
Derivative [Line Items]
Gross Notional	9,883,000	0
Fair Value Assets	280,323	0
Fair Value Liabilities	(173,863)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Total Return Swap
Derivative [Line Items]
Gross Notional	15,129,666	0
Fair Value Assets	66,627	0
Fair Value Liabilities	(475,209)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: \| Equity Futures
Derivative [Line Items]
Gross Notional	5,015,002	0
Fair Value Assets	736	0
Fair Value Liabilities	$ (6,595)	$ 0

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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