Investments Investments (Allowance for Credit Loss Roll Forward) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance	$ 37	$ 31
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	45	24
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	(10)	(7)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	3	7
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	75	55
Corporate Debt Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance	27	26
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	44	18
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	(10)	(6)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	1	5
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	62	43
Asset-backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance	10	0
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0	5
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	0	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	2	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	12	5
Commercial Mortgage Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance	0	1
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	1	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	0	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	0	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	1	1
Debt Security, Government, Non-US [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance	0	4
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0	1
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	0	(1)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	0	2
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	$ 0	$ 6