Pension And Postretirement Benefits (Pension And Postretirement Benefit Costs Included In Operating Expenses) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$ (1,888)	$ (1,699)	$ (432)		$ 4,048	$ (2,726)
Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (credit) cost	1,400			$ (233)	2,727	(3,488)
Pension Benefit [Member] | Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	260			270	743	845
Interest cost on benefit obligation	463			551	1,520	1,542
Expected return on assets	(905)			(761)	(2,636)	(2,276)
Amortization of prior service credit	(28)			(28)	(85)	(87)
Actuarial (gain) loss	1,888			0	4,019	(1,796)
Net (credit) cost	1,678			32	3,561	(1,772)
Postretirement Benefit [Member] | Qualified Plan [Member] | Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	19			27	55	82
Interest cost on benefit obligation	185			196	557	582
Expected return on assets	(57)			(76)	(169)	(228)
Amortization of prior service credit	(425)			(412)	(1,277)	(1,222)
Actuarial (gain) loss	0			0	0	(930)
Net (credit) cost	$ (278)			$ (265)	$ (834)	$ (1,716)