Investments (Narrative) (Details)	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2023 USD ($) loan item	Sep. 30, 2023 USD ($) loan item	Dec. 31, 2022 USD ($) loan item
Schedule of Investments [Line Items]
Decrease in gross AFS securities unrealized gains (losses)		$ 1,400,000,000
Number of partnerships in alternative investment portfolio \| item	337	337	328
Alternative investments as a percentage of overall invested assets		2.00%	2.00%
Fair value of collateral received that we are permitted to sell or re-pledge	$ 25,000,000	$ 25,000,000
Securities that have been re-pledged	0	0
Investment commitments	2,300,000,000	2,300,000,000
Investment commitments for limited partnerships	1,800,000,000	1,800,000,000
Investment commitments for private placements	217,000,000	217,000,000
Investment commitments for mortgage loans on real estate	257,000,000	257,000,000
Fixed maturity AFS securities	100,387,000,000	100,387,000,000	$ 99,465,000,000
Asset Pledged as Collateral [Member]
Schedule of Investments [Line Items]
Fixed maturity AFS securities	87,000,000	87,000,000
Derivative Counterparties [Member]
Schedule of Investments [Line Items]
Fair value of collateral received that we are permitted to sell or re-pledge	1,000,000,000.0	1,000,000,000.0
Securities that have been re-pledged	$ 335,000,000	$ 335,000,000
Minimum [Member]
Schedule of Investments [Line Items]
Percentage of the fair value of securities obtained as collateral under reverse repurchase agreements.	80.00%	80.00%
Maximum [Member]
Schedule of Investments [Line Items]
Percentage of the fair value of securities obtained as collateral under reverse repurchase agreements.	95.00%	95.00%
Loan modifications	$ 1,000,000	$ 1,000,000
Mortgage Loans On Real Estate [Member] \| Commercial [Member]
Schedule of Investments [Line Items]
Impaired financing receivable, principal balance	$ 3,000,000	$ 3,000,000
Mortgage Loans On Real Estate [Member] \| Commercial [Member] \| Maximum [Member]
Schedule of Investments [Line Items]
Impaired financing receivable, principal balance			$ 1,000,000
Mortgage Loans On Real Estate [Member] \| Residential [Member]
Schedule of Investments [Line Items]
Number of loans past due \| loan	89	89	73
Financing Receivable, Number of Loans In Foreclosure \| loan	66	66	49
Financing Receivable, 90 Days or More Past Due, Still Accruing	$ 30,000,000	$ 30,000,000	$ 21,000,000
Number of impaired loans \| loan	67	67	37
Impaired financing receivable, principal balance	$ 34,000,000	$ 34,000,000	$ 16,000,000
Geographic Concentration Risk [Member] \| Mortgage Loans On Real Estate [Member] \| Commercial [Member] \| California [Member]
Schedule of Investments [Line Items]
Concentration risk, percentage		28.00%	28.00%
Geographic Concentration Risk [Member] \| Mortgage Loans On Real Estate [Member] \| Commercial [Member] \| Texas [Member]
Schedule of Investments [Line Items]
Concentration risk, percentage		10.00%	9.00%
Geographic Concentration Risk [Member] \| Mortgage Loans On Real Estate [Member] \| Residential [Member] \| California [Member]
Schedule of Investments [Line Items]
Concentration risk, percentage		14.00%	17.00%
Geographic Concentration Risk [Member] \| Mortgage Loans On Real Estate [Member] \| Residential [Member] \| NEW JERSEY
Schedule of Investments [Line Items]
Concentration risk, percentage			12.00%
Geographic Concentration Risk [Member] \| Mortgage Loans On Real Estate [Member] \| Residential [Member] \| NEW YORK
Schedule of Investments [Line Items]
Concentration risk, percentage		13.00%
Corporate Bonds [Member]
Schedule of Investments [Line Items]
Percentage of fair value rated as investment grade	96.00%	96.00%	96.00%
Amortized cost of portfolio rated below investment grade	$ 3,200,000,000	$ 3,200,000,000	$ 3,500,000,000
Fair value of portfolio rated below investment grade	3,000,000,000.0	3,000,000,000.0	3,300,000,000
Securities [Member] \| White Chapel LLC [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value	1,000,000,000.0	1,000,000,000.0
Securities Investment [Member] \| White Chapel V LLC [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value	1,300,000,000	$ 1,300,000,000
Securities Investment [Member] \| White Chapel LLC [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value			$ 1,000,000,000.0
Concentration risk, percentage		1.00%	1.00%
Securities Investment [Member] \| Financial Service [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value	19,500,000,000	$ 19,500,000,000	$ 19,200,000,000
Concentration risk, percentage		14.00%	15.00%
Securities Investment [Member] \| Consumer Non-Cyclical Industry [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value	$ 14,500,000,000	$ 14,500,000,000	$ 14,300,000,000
Concentration risk, percentage		11.00%	11.00%
Securities Investment [Member] \| Federal Home Loan Mortgage Corporation [Member] \| Investments [Member]
Schedule of Investments [Line Items]
Fair value			$ 702,000,000
Concentration risk, percentage			1.00%

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Amortized cost of portfolio rated below investment grade.

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This item represents the change in gross unrealized holding gain or loss on available-for-sale securities that has been included in accumulated other comprehensive income, a separate component of shareholders' equity, during the period.

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Percentage of the fair value of portfolio that was rated investment grade as of balance sheet date.

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Financing Receivable, Number of Loans In Foreclosure

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Number of partnerships represented in alternative investment portfolio.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Fair value of the collateral, or portion thereof, that has been re-pledged, delivered, or otherwise used.

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Amortized cost of financing receivable modified during period for debtor experiencing financial difficulty.

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