Derivative Instruments - Effects of Qualifying and Non-Qualifying Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)	$ (97.0)	$ (162.0)	$ 269.0	$ (409.0)
Net investment income	1,510.0	1,366.0	2,983.0	2,713.0
Benefits	1,601.0	1,608.0	3,335.0	3,377.0
Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)	(97.0)	(162.0)	269.0	(409.0)
Net investment income	1,510.0	1,366.0	2,983.0	2,713.0
Benefits	1,601.0	1,608.0	3,335.0	3,377.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate contracts, amount of gain or (loss) reclassified from AOCI into income	0.0	0.0	0.0	0.0
Foreign currency contracts, amount of gain or (loss) reclassified from AOCI into income	0.0	0.0	1.0	3.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Interest rate contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Interest rate contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	(44.0)	(94.0)	(18.0)	(12.0)
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Foreign currency contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Foreign currency contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	(3.0)	2.0	(5.0)
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Equity market contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	3,693.0	1,133.0	2,749.0	25.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Credit contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	(1.0)	1.0	(1.0)	2.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | LPR ceded derivative | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Reinsurance-related | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	(38.0)	(72.0)	231.0	(267.0)
Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | RILA, fixed indexed annuity and IUL contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	(3,314.0)	(2,015.0)	(1,762.0)	(392.0)
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate contracts, amount of gain or (loss) reclassified from AOCI into income	0.0	1.0	0.0	1.0
Foreign currency contracts, amount of gain or (loss) reclassified from AOCI into income	15.0	12.0	31.0	27.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Interest rate contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	(4.0)	3.0	(5.0)	14.0
Derivatives designated as hedging instruments	4.0	(3.0)	5.0	(14.0)
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Interest rate contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Foreign currency contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0.0	2.0	(1.0)	3.0
Derivatives designated as hedging instruments	0.0	(2.0)	1.0	(3.0)
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Foreign currency contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Equity market contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Credit contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | LPR ceded derivative | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Reinsurance-related | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | RILA, fixed indexed annuity and IUL contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate contracts, amount of gain or (loss) reclassified from AOCI into income	0.0	0.0	0.0	0.0
Foreign currency contracts, amount of gain or (loss) reclassified from AOCI into income	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Interest rate contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Interest rate contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Foreign currency contracts | Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Foreign currency contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Equity market contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Credit contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | LPR ceded derivative | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	(5.0)	(8.0)	28.0	(8.0)
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | Reinsurance-related | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	0.0	0.0	0.0	0.0
Location, Statement of Income, Balance [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet | RILA, fixed indexed annuity and IUL contracts | Non-Qualifying Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Non-Qualifying Hedges	$ 0.0	$ 0.0	$ 0.0	$ 0.0