Investments Investments (Allowance for Credit Loss Roll Forward) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Dec. 31, 2024
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 232	$ 103	$ 210	$ 98
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	64	10
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	(56)	(2)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	14	(2)
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	(1)
Corporate Debt Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	211	88	189	82
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	64	10
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	(56)	(2)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	14	(1)
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	(1)
Asset-backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	21	15	21	15
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	0	0
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	0
Commercial Mortgage Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0	0	$ 1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	0	(1)
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	$ 0
Debt Security, Government, Non-US [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 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
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-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
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-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
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-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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-22

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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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147476148/220-40-50-22

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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 sale.

+ References

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

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- Definition

Amount of foreign currency translation gain (loss) which decreases (increases) allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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