Segment Information (Summary Of Operating Revenues And Expenses By Segment) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Operations and Support Expenses	$ 107,307	$ 90,289	$ 112,155
Number of reportable segments | segment	2
Corporate, non-segment [Member]
Segment Reporting Information [Line Items]
Operations and Support Expenses	$ 2,494	2,063	2,088
Corporate, non-segment [Member] | Revision of Prior Period, Reclassification, Adjustment [Member]
Segment Reporting Information [Line Items]
Operations and Support Expenses		$ 270	$ 1,310