Pension, OPEB and Savings Plans (Pre-Tax Changes Recognized In Accumulated Other Comprehensive Income (Loss), Regulatory Assets And Deferred Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net Actuarial (Gain) Loss in Current Period	$ 369	$ 55
Amortization of Net Actuarial Gain (Loss)	(85)	(97)
Prior Service Cost (Credit) in current period	0	0
Amortization of Prior Service Credit	18	18
Total	302	(24)
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net Actuarial (Gain) Loss in Current Period	(145)	156
Amortization of Net Actuarial Gain (Loss)	(64)	(50)
Prior Service Cost (Credit) in current period	(559)	0
Amortization of Prior Service Credit	1	11
Total	$ (767)	$ 117