Future Policy Benefits (Liabilities for Unpaid Claims - Methodology) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-duration Insurance Contract, Discounted Liability, Discount	$ 1,672
Group Benefits
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Insurance Contract, Discounted Liability, Interest Accretion, Statement of Financial Position [Extensible Enumeration]	Policyholder benefits and claims	Policyholder benefits and claims	Policyholder benefits and claims
Group Long-Term Disability | Group Benefits
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contracts, Discounted Liabilities, Amount	$ 6,800	$ 6,700
Short-duration Insurance Contract, Discounted Liability, Discount	1,500	1,300
Short-duration Insurance Contracts, Discounted Liabilities, Interest Accretion	$ 464	516	$ 461
Group Long-Term Disability | Minimum | Group Benefits
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contract, Discounted Liability, Discount Rate	3.00%
Group Long-Term Disability | Maximum | Group Benefits
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contract, Discounted Liability, Discount Rate	8.00%
Group Life - Term | Asia
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contracts, Discounted Liabilities, Amount	$ 1,200	1,300
Short-duration Insurance Contract, Discounted Liability, Discount	166	163
Short-duration Insurance Contracts, Discounted Liabilities, Interest Accretion	$ 44	$ 37	$ 22
Group Life - Term | Minimum | Asia
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contract, Discounted Liability, Discount Rate	1.00%
Group Life - Term | Maximum | Asia
Liability for Claims and Claims Adjustment Expense [Line Items]
Short-Duration Contract, Discounted Liability, Discount Rate	7.00%