Investments, Allowance for Credit Losses (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Dec. 31, 2019
Investments [Abstract]
Accrued interest receivables on available-for-sale fixed maturity securities		$ 390
Allowance for Credit Losses [Roll Forward]
Balance as of December 31, 2019		0
Total allowance for credit losses	[1]	49
ASU 2016-13 [Member]
Allowance for Credit Losses [Roll Forward]
Balance as of December 31, 2019		6
Impact of adopting ASU 2016-13			$ (5)
Corporate and Other Bonds [Member]
Allowance for Credit Losses [Roll Forward]
Balance as of December 31, 2019		0
Additions to allowance for securities for which credit losses were not previously recorded		48
Additions to allowance for available-for-sale securities accounted for as PCD assets		1
Reductions for securities sold during the period (realized)		(5)
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)
Total allowance for credit losses	[1]	$ 49
Corporate and Other Bonds [Member] | ASU 2016-13 [Member]
Allowance for Credit Losses [Roll Forward]
Impact of adopting ASU 2016-13			$ 6

[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.