Pension And Postretirement Benefits (Pension And Postretirement Benefit Costs Included In Operating Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$ 432	$ (930)
Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (credit) cost	59	(1,196)
Pension Benefit [Member] | Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	240	291
Interest cost on benefit obligation	549	487
Expected return on assets	(851)	(760)
Amortization of prior service credit	(33)	(30)
Actuarial (gain) loss	432	0
Net (credit) cost	337	(12)
Postretirement Benefit [Member] | Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	18	29
Interest cost on benefit obligation	186	191
Expected return on assets	(56)	(77)
Amortization of prior service credit	(426)	(397)
Actuarial (gain) loss	0	(930)
Net (credit) cost	$ (278)	$ (1,184)