Segment Information (Summary Of Operating Revenues And Expenses) (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023 USD ($) segment	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Segment Reporting Information Operations And Support Expenses	$ 19,506	$ 19,713
Number of reportable segments | segment	2
Corporate, non-segment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information Operations And Support Expenses	$ 692	$ 626
Corporate, non-segment [Member] | Revision of Prior Period, Reclassification, Adjustment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information Operations And Support Expenses			$ 2,400,000