Investmenst (Changes In Allowance For Credit Losses On Mortgage Loans On Real Estate) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule of Investments [Line Items]
Balance as of beginning-of-year	$ 183	$ 160	$ 203	$ 2
Additions (reductions) from provision for credit loss expense	(14)	111	(34)	182
Additions from purchases of PCD mortgage loans on real estate
Balance as of end-of-year	169	271	169	271
Changes in economic assumptions increasing provision	(14)	111	(34)	182
Accrued interest receivable excluded from credit losses	50	52	50	52
Commercial [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-year	171	125	186
Additions (reductions) from provision for credit loss expense	(16)	109	(31)	173
Additions from purchases of PCD mortgage loans on real estate
Balance as of end-of-year	155	234	155	234
Residential [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-year	12	35	17	2
Additions (reductions) from provision for credit loss expense	2	2	(3)	9
Additions from purchases of PCD mortgage loans on real estate
Balance as of end-of-year	14	37	14	37
Residential [Member] | Unfunded Loan Commitment [Member]
Schedule of Investments [Line Items]
Changes in economic assumptions increasing provision	$ 1	$ 1	$ 2
Cumulative Effect, Period of Adoption, Adjustment [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-year				87
Cumulative Effect, Period of Adoption, Adjustment [Member] | Commercial [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-year				61
Cumulative Effect, Period of Adoption, Adjustment [Member] | Residential [Member]
Schedule of Investments [Line Items]
Balance as of beginning-of-year				$ 26