Fair Value Measurements (excluding Consolidated Investment Entities) - Other Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held in separate accounts	$ 84,569	$ 80,174
Derivatives	376	389
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	30,468	30,357
Equity securities	308	336
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	2,003	2,454
Derivatives	342	422
Other investments	70	68
Assets held in separate accounts	84,569	80,174
Short-term debt	143	141
Long-term debt	2,094	2,094
Carrying Value | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	376	389
Carrying Value | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	72	95
Derivatives	49	46
Carrying Value | Managed custody guarantees
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	3	6
Carrying Value | Funding agreements without fixed maturities and deferred annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	34,958	35,707
Carrying Value | Funding agreements with fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	1,360	1,285
Carrying Value | Supplementary contracts, immediate annuities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	701	727
Carrying Value | Mortgage loans on real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	5,346	5,445
Carrying Value | Policy loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	359	363
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, including securities pledged	30,468	30,357
Equity securities	308	336
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreements	2,003	2,454
Derivatives	342	422
Other investments	70	68
Assets held in separate accounts	84,569	80,174
Short-term debt	144	142
Long-term debt	1,935	1,935
Estimate of Fair Value Measurement | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	376	389
Estimate of Fair Value Measurement | Embedded derivative on reinsurance
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	72	95
Derivatives	49	46
Estimate of Fair Value Measurement | Managed custody guarantees
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	3	6
Estimate of Fair Value Measurement | Funding agreements without fixed maturities and deferred annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	36,635	36,385
Estimate of Fair Value Measurement | Funding agreements with fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	1,358	1,281
Estimate of Fair Value Measurement | Supplementary contracts, immediate annuities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed benefit derivatives	640	636
Estimate of Fair Value Measurement | Mortgage loans on real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	5,078	5,149
Estimate of Fair Value Measurement | Policy loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	$ 359	$ 363