Commitments And Contingencies (Schedule Of Reconciliation Of Beginning And Ending Accrued Litigated Claims And Non-Litigated Claims) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018
Commitments and Contingencies [Line Items]
Change in estimate	$ 53
Litigated Claims And Non-Litigated Claims [Member]
Commitments and Contingencies [Line Items]
Balance at the beginning of the period	28		$ 22
Provision for termite damage claims	95	[1]	39
Cash payments	(44)		(33)
Balance at the end of the period	$ 80		$ 28

[1] Includes a change in estimate of $53 million, as described above.