Investment And Other Income (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Investment And Other Income [Abstract]
OPEB Remeasurement	$ 46	$ 12	$ (20)	$ 84	$ 38	$ 234