Investments, Allowance for Credit Losses (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Investments [Abstract]
Accrued interest receivables on available-for-sale fixed maturity securities	$ 371
Allowance for Credit Losses [Roll Forward]
Beginning balance	0
Additions to allowance for securities for which credit losses were not previously recorded	79
Additions to allowance for available-for-sale securities accounted for as PCD assets	5
Reductions for securities sold during the period (realized)	22
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 (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	(27)
Total allowance for credit losses	40	[1]
ASC 326 [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance	6
Cumulative Effect, Period of Adoption, Adjustment [Member] | ASC 326 [Member]
Allowance for Credit Losses [Roll Forward]
Total allowance for credit losses	6
Corporate and Other Bonds [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance	0
Additions to allowance for securities for which credit losses were not previously recorded	67
Additions to allowance for available-for-sale securities accounted for as PCD assets	5
Reductions for securities sold during the period (realized)	22
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 (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	(32)
Total allowance for credit losses	23	[1]
Corporate and Other Bonds [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | ASC 326 [Member]
Allowance for Credit Losses [Roll Forward]
Total allowance for credit losses	6
Asset-Backed [Member]
Allowance for Credit Losses [Roll Forward]
Beginning balance	0
Additions to allowance for securities for which credit losses were not previously recorded	12
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	5
Total allowance for credit losses	$ 17	[1]

[1] On January 1, 2020, the Company adopted ASU 2016-13; see Note 1. The Unrealized OTTI Losses (Gains) column that tracked subsequent valuation changes on securities for which a credit loss had previously been recorded has been replaced with the Allowance for Credit Losses column. Prior period amounts were not adjusted for the adoption of this standard.