Commitments And Contingencies (Schedule Of Reconciliation Of Beginning And Ending Accrued Self-Insured Claims) (Details) - Accrued self-insured claims, net - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Commitments and Contingencies [Line Items]
Balance at the beginning of the period	$ 111	$ 111
Provision for self-insured claims	24	18
Cash payments	(16)	(14)
Balance at the end of the period	$ 119	$ 115