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, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	$ 670	$ 637	$ 616
Capitalized deferred policy acquisition costs	993	948	889
Amortized deferred policy acquisition costs	(946)	(913)	(863)
Shadow deferred policy acquisition costs	21	(2)	(5)
Deferred policy acquisition costs asset at December 31	738	670	637
Consolidated Property and Casualty Insurance Entity [Member]
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	438	408	388
Capitalized deferred policy acquisition costs	933	897	840
Amortized deferred policy acquisition costs	(907)	(867)	(820)
Deferred policy acquisition costs asset at December 31	464	438	408
Life Insurance Product Line [Member]
Deferred Costs [Roll Forward]
Deferred policy acquisition costs asset at January 1	232	229	228
Capitalized deferred policy acquisition costs	60	51	49
Amortized deferred policy acquisition costs	(39)	(46)	(43)
Shadow deferred policy acquisition costs	21	(2)	(5)
Deferred policy acquisition costs asset at December 31	$ 274	$ 232	$ 229