Investmenst (Changes In Allowance For Credit Losses On Mortgage Loans On Real Estate) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Balance as of beginning-of-period		$ 2	$ 2
Additions from provision for credit loss expense	$ 4		182
Additions from purchases of PCD mortgage loans on real estate		160		$ 2
Additions (reductions) for mortgage loans on real estate for which credit losses were previously recognized	107
Balance as of end-of-period	271		271	2
Changes in economic assumptions increasing provision	111		182
Accrued interest receivable excluded from credit losses	52		52
Cumulative Effect, Period of Adoption, Adjustment [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-period		87	87
Balance as of end-of-period				87
Unfunded Loan Commitment [Member]
Schedule of Investments [Line Items]
Additions (reductions) for mortgage loans on real estate for which credit losses were previously recognized	1		0
Commercial [Member]
Schedule of Investments [Line Items]
Additions from provision for credit loss expense	3		173
Additions from purchases of PCD mortgage loans on real estate		125
Additions (reductions) for mortgage loans on real estate for which credit losses were previously recognized	106
Balance as of end-of-period	234		234
Commercial [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-period		61	61
Balance as of end-of-period				61
Residential [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-period		2	2
Additions from provision for credit loss expense	1		9
Additions from purchases of PCD mortgage loans on real estate		35		2
Additions (reductions) for mortgage loans on real estate for which credit losses were previously recognized	1
Balance as of end-of-period	$ 37		37	2
Residential [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-period		$ 26	$ 26
Balance as of end-of-period				$ 26