Supplementary Financial Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Supplementary Financial Information [Abstract]
Interest	$ 84	$ 80
Less capitalized interest	(3)	(3)
Interest payments (net of amounts capitalized)	81	77
Construction expenditures financed through accounts payable (investing)	194	182
ROU assets obtained in exchange for operating lease obligations (investing)	$ 13	$ 7

Future cash outflow to pay for construction in progress expenditures that have occurred.

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