Investment And Other Income (Components Of Investment And Other Income (Loss)) (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]
Interest and dividend income	$ 22			$ 16	$ 60	$ 24
Pension benefit	5			24	14	74
OPEB costs	(2)			(5)	(7)	(13)
OPEB remeasurement gain	46	$ 12	$ (20)	84	38	234
Pension remeasurement gain				91		91
All other, net	(4)			1	(4)
Total investment and other income, net	$ 67			$ 211	$ 101	$ 410