Fair Value of Financial Instruments - Carrying and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	$ 278,356	$ 266,513
Liabilities	(18,301)	(16,962)
Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	232	288
Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	392	233
Fair Value | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	19,647	17,047
Fair Value | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	6,588	5,015
Fair Value | Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	2,476	2,476
Fair Value | Cash and invested cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	5,801	3,365
Fair Value | Policyholder account balances and other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(30,505)	(31,611)
Fair Value | Short-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(299)	(249)
Fair Value | Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(5,304)	(5,182)
Fair Value | Funds withheld reinsurance-related liabilities – excluding embedded derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(16,877)	(17,089)
Carrying Amount | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	21,083	18,963
Carrying Amount | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	6,588	5,015
Carrying Amount | Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	2,476	2,476
Carrying Amount | Cash and invested cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	5,801	3,365
Carrying Amount | Policyholder account balances and other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(40,394)	(40,027)
Carrying Amount | Short-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(300)	(250)
Carrying Amount | Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(5,856)	(5,699)
Carrying Amount | Funds withheld reinsurance-related liabilities – excluding embedded derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(16,877)	(17,089)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	810	823
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Cash and invested cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Policyholder account balances and other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Short-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value | Funds withheld reinsurance-related liabilities – excluding embedded derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Significant Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	265,955	255,563
Liabilities	(4,052)	(4,555)
Significant Observable Inputs (Level 2) | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Significant Observable Inputs (Level 2) | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	369	233
Significant Observable Inputs (Level 2) | Fair Value | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	19,647	17,047
Significant Observable Inputs (Level 2) | Fair Value | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	1,119	667
Significant Observable Inputs (Level 2) | Fair Value | Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	2,476	2,476
Significant Observable Inputs (Level 2) | Fair Value | Cash and invested cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	5,801	3,365
Significant Observable Inputs (Level 2) | Fair Value | Policyholder account balances and other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Significant Observable Inputs (Level 2) | Fair Value | Short-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(299)	(249)
Significant Observable Inputs (Level 2) | Fair Value | Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(5,304)	(5,182)
Significant Observable Inputs (Level 2) | Fair Value | Funds withheld reinsurance-related liabilities – excluding embedded derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	11,591	10,127
Liabilities	(14,249)	(12,407)
Significant Unobservable Inputs (Level 3) | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	232	288
Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	23	0
Significant Unobservable Inputs (Level 3) | Fair Value | Mortgage loans on real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Significant Unobservable Inputs (Level 3) | Fair Value | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	5,469	4,348
Significant Unobservable Inputs (Level 3) | Fair Value | Policy loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Significant Unobservable Inputs (Level 3) | Fair Value | Cash and invested cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets	0	0
Significant Unobservable Inputs (Level 3) | Fair Value | Policyholder account balances and other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	(30,505)	(31,611)
Significant Unobservable Inputs (Level 3) | Fair Value | Short-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Significant Unobservable Inputs (Level 3) | Fair Value | Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	0	0
Significant Unobservable Inputs (Level 3) | Fair Value | Funds withheld reinsurance-related liabilities – excluding embedded derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities	$ (16,877)	$ (17,089)