Investments, Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Investments [Abstract]
Accrued interest receivables on available-for-sale fixed maturity securities	$ 387	$ 390	$ 387	$ 390	$ 371
Allowance for Credit Losses [Roll Forward]
Beginning balance	45	51	40	0
Additions to allowance for securities for which credit losses were not previously recorded		4	14	74
Additions to allowance for available-for-sale securities accounted for as PCD assets	2	1	8	3
Reductions for securities sold during the period (realized)		9	6	15
Write-offs charged against the allowance	16		16
Reductions for intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis				1
Additional increases or (decrease) to the allowance for credit losses on securities that had an allowance recorded in a previous period			(9)	(20)
Total allowance for credit losses	31	47	31	47
Cumulative Effect, Period of Adoption, Adjustment [Member] | ASC 326 [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance				6
Corporate and Other Bonds [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance	24	39	23	0
Additions to allowance for securities for which credit losses were not previously recorded		4	14	62
Additions to allowance for available-for-sale securities accounted for as PCD assets	2	1	4	3
Reductions for securities sold during the period (realized)		9	6	15
Write-offs charged against the allowance	16		16
Reductions for intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis				1
Additional increases or (decrease) to the allowance for credit losses on securities that had an allowance recorded in a previous period		(1)	(9)	(21)
Total allowance for credit losses	10	34	10	34
Corporate and Other Bonds [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | ASC 326 [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance				6
Asset-Backed [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance	21	12	17	0
Additions to allowance for securities for which credit losses were not previously recorded				12
Additions to allowance for available-for-sale securities accounted for as PCD assets			4
Additional increases or (decrease) to the allowance for credit losses on securities that had an allowance recorded in a previous period		1		1
Total allowance for credit losses	$ 21	$ 13	$ 21	$ 13