Investments Investments (Allowance for Credit Loss Roll Forward) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024	Dec. 31, 2023
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 161	$ 120	$ 161	$ 120	$ 132	$ 98	$ 111	$ 75
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	25	10	70	42
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	(2)	0	(4)	(9)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	5	(1)	(3)	11
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	1	0	0	0
Allowance for Loan and Lease Losses, Real Estate	113	87	113	87	107	93	75	67
Allowance For Loan and Lease Losses Provision Of Credit Losses	6	12	20	28
Provision (release)	0	0	0	(8)
Commercial Real Estate
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Allowance for Loan and Lease Losses, Real Estate	108	87	108	87	103	93	75	67
Allowance For Loan and Lease Losses Provision Of Credit Losses	5	12	15	28
Provision (release)	0	0	0	(8)
Residential Real Estate
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Allowance for Loan and Lease Losses, Real Estate	5	0	5	0	4	0	0	0
Allowance For Loan and Lease Losses Provision Of Credit Losses	1	0	5	0
Provision (release)	0	0	0	0
Corporate Debt Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	141	104	141	104	112	82	95	62
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	25	10	66	42
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	(2)	0	(4)	(9)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	5	(1)	(3)	8
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	1	0	0	0
Asset-backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Allowance for Credit Loss	19	15	19	15	19	15	15	12
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	0	0	4	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	0	0	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	0	0	0	(3)
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	0	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	1	1	1	1	$ 1	1	$ 1	$ 1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded	0	0	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	0	0	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	0	0	0	0
Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation	0	0	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			$ 0
Available-for-sale Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense	0	0	0	1
Available-for-sale Securities [Member] | Corporate Debt Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense	0	0	0	1
Available-for-sale Securities [Member] | Asset-backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense	0	0	0	0
Available-for-sale Securities [Member] | Commercial Mortgage Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense	$ 0	$ 0	$ 0	$ 0