Fair Value of Assets and Liabilities Fair Value of Assets and Liabilities (Quantitative Information for Level 3 Inputs) (Details) $ in Millions	Mar. 31, 2024 USD ($)		Dec. 31, 2023 USD ($)
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (68,810)	[1]	$ (61,924)	[2]
Corporate Debt Securities [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (160)		$ (91)
Corporate Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.01		0.01
Corporate Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.02		0.02
Corporate Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0		0
Asset-backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (292)		$ (268)
Asset-backed Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.02		0.02
Asset-backed Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.09		0.18
Asset-backed Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0		0
US Government Agencies Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (6)		$ (7)
US Government Agencies Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.01		0.01
US Government Agencies Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.01		0.01
US Government Agencies Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0		0
Equity securities | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (29)		$ (31)
Equity securities | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	0.04		0.04
Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets, Fair Value Disclosure	$ (6)		$ (50)
Embedded Derivatives In Indexed Annuity [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 398		$ 415
Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.02		0.02
Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.04		0.04
Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.01		0.01
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.02		0.02
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.04		0.04
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.01		0.01
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0		0
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.05		0.05
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0		0
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.04		0.04
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.10		0.05
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0		0
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.04		0.04
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.10		0.05
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0		0
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.18		0.18
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.35		0.35
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0		0
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.17		0.17
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.35		0.35
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0		0
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0.03		0.03
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	1		1
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Asset, Measurement Input	0		0
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.03		0.03
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	1		1
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0		0
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	8.9		7.1
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	11.0		8.5
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Instrument, Measurement Input	6.7		6
Measurement Input, EBITDA Multiple [Member] | Equity securities | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Equity Securities, FV-NI, Measurement Input	10.4		10.1
Measurement Input, EBITDA Multiple [Member] | Equity securities | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Equity Securities, FV-NI, Measurement Input	12.4		12.3
Measurement Input, EBITDA Multiple [Member] | Equity securities | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Equity Securities, FV-NI, Measurement Input	6.9		8.4

[1] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of March 31, 2024, the fair value of such investments was $893 million.

[2] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of December 31, 2023, the fair value of such investments was $856 million