Deferred Policy Acquisition Costs (Deferred Policy Acquisition Costs And Asset Reconciliation Including The Amortized Deferred Policy Acquisition Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	$ 774	$ 738	$ 670
Capitalized deferred policy acquisition costs	1,145	1,095	993
Amortized deferred policy acquisition costs	(1,106)	(1,034)	(946)
Shadow deferred policy acquisition costs	(8)	(25)	21
Deferred policy acquisition costs asset at December 31	805	774	738
Life Insurance Segment
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	262	274	232
Capitalized deferred policy acquisition costs	58	61	60
Amortized deferred policy acquisition costs	(49)	(48)	(39)
Shadow deferred policy acquisition costs	(8)	(25)	21
Deferred policy acquisition costs asset at December 31	263	262	274
Consolidated Property And Casualty Insurance Entity
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	512	464	438
Capitalized deferred policy acquisition costs	1,087	1,034	933
Amortized deferred policy acquisition costs	(1,057)	(986)	(907)
Deferred policy acquisition costs asset at December 31	$ 542	$ 512	$ 464