Investments Investments (Allowance for Credit Loss Roll Forward) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
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	$ 31	$ 20
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	11	6
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	(2)	(3)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	2	1
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance	42	22
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	26	17
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	6	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	(1)	(1)
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	33	16
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	0	0
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	5	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	5	0
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	1	3
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	(2)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	0	1
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	4	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	(1)	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	$ 3	$ 5