Commitments And Contingencies (Schedule Of Reconciliation Of Beginning And Ending Accrued Self-Insured Claims) (Details) - Accrued Self-Insured Claims, Net [Member] - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies [Line Items]
Balance at the beginning of the period	$ 111	$ 111
Provision for self-insured claims	35	26
Cash payments	(21)	(28)
Balance at the end of the period	$ 125	$ 108