Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands		Sep. 30, 2025	Dec. 31, 2024
Other Invested Assets [Line Items]
Other invested assets	[1]	$ 2,312,006	$ 1,582,094
Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		2,167,242	1,533,210
Derivative Instruments
Other Invested Assets [Line Items]
Other invested assets		99,305	24,499
Other
Other Invested Assets [Line Items]
Other invested assets		45,459	24,385
Equity Method | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		2,080,947	1,489,086
Equity Method | Private equity | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		394,339	388,822
Equity Method | Hedge funds | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		1,615,969	1,024,534
Equity Method | Real estate-related | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		70,639	75,730
Fair Value | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		86,295	44,124
Fair Value | Private equity | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		21,316	28,094
Fair Value | Hedge funds | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		49,614	14
Fair Value | Real estate-related | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets		$ 15,365	$ 16,016

[1] The table below provides a summary of the gross notional amount and fair value of derivative contracts by the primary underlying risks, excluding embedded derivatives and associated reinsurance recoverables and deposit receivables. Many derivative instruments contain multiple underlying risks. The fair value amounts below represent the value of derivative contracts prior to taking into account the netting effects of master netting agreements and cash collateral.  September 30, 2025December 31, 2024Primary Underlying Risk/Instrument Type Fair Value Fair ValueGross NotionalAssetsLiabilitiesGross NotionalAssetsLiabilities (in thousands)Derivatives Designated as Hedge Accounting Instruments:Currency/Interest RateInterest Rate Swaps$2,711 $0 $(126)$2,851 $0 $(209)Foreign Currency Swaps4,339,466 88,554 (213,498)3,308,842 202,606 (27,523)Total Derivatives Designated as Hedge Accounting Instruments$4,342,177 $88,554 $(213,624)$3,311,693 $202,606 $(27,732)Derivatives Not Qualifying as Hedge Accounting Instruments:Interest RateInterest Rate Swaps$193,248,460 $8,054,508 $(19,736,940)$174,170,160 $9,029,399 $(20,888,553)Interest Rate Futures1,817,500 1,014 (2,051)1,518,400 1,967 (1,443)Interest Rate Options26,725,000 110,164 (1,204,126)29,135,000 279,414 (1,406,265)Interest Rate Forwards0 0 0 0 0 0 Interest Rate Total Return Swaps341,6694,8820 223,721 1,472 (2,121)Foreign CurrencyForeign Currency Forwards2,316,193 10,343 (7,047)1,146,861 30,078 (181)CreditCredit Default Swaps849,9508,7420 911,850 9,606 0 Currency/Interest RateForeign Currency Swaps2,225,11161,881 (50,429)2,285,052 164,152 (9,277)EquityEquity Total Return Swaps28,343,850 2,602,653 (2,473,843)23,025,217 1,160,080 (1,182,913)Equity Options211,675,759 9,174,115 (7,346,036)117,107,059 4,453,762 (3,717,637)Equity Futures813,379 1,692 (908)1,802,205 15 (6,060)Synthetic GICs4,180,490 0 0 3,958,847 143 (31)Total Derivatives Not Qualifying as Hedge Accounting Instruments$472,537,361 $20,029,994 $(30,821,380)$355,284,372 $15,130,088 $(27,214,481)Total Derivatives(1)(2)$476,879,538 $20,118,548 $(31,035,004)$358,596,065 $15,332,694 $(27,242,213) (1)Excludes embedded derivatives which contain multiple underlying risks. The fair value of these embedded derivatives was a net liability of $17,025 million and $11,968 million as of September 30, 2025 and December 31, 2024, respectively, primarily included in "Policyholders' account balances". (2)Recorded in “Other invested assets”, “Payables to parent and affiliates” and "Other liabilities" on the Unaudited Interim Consolidated Statements of Financial Position.