Investments - Investments - ACL on Fixed Maturities (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	$ (12)	$ (1)	$ (23)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	9	20	2
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(5)	(4)	(18)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Sell before Recovery	0	(3)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	5	1	(6)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff	0	3	0
Ending Balance	(21)	(12)	(1)
CMBS
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	(10)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	0	7
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Sell before Recovery	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	2	3
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff	0	0
Ending Balance	(12)	(10)	0
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	(2)	(1)	(23)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	9	10	2
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(5)	(3)	(18)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Sell before Recovery	0	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	3	(3)	(6)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff	0	3	0
Ending Balance	(9)	(2)	(1)
Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning Balance	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded		3
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold		(1)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Sell before Recovery		(3)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)		1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff		0
Ending Balance	$ 0	$ 0	$ 0

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

Amount of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from intent to sell or more likely than not will be required to sell before recovery of amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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