Postretirement Plans (Reconciliation Of Level 3 Assets Held) (Details) - Pension Plans [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		$ 64,011	$ 56,692
Net Realized and Unrealized Gains/(Losses)		(2,585)	8,552
Net Purchases, Issuances and Settlements		(764)	(744)
Ending balance at fair value		56,102	64,011
Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		315	350
Net Realized and Unrealized Gains/(Losses)		(3)	9
Net Purchases, Issuances and Settlements		3	(40)
Net Transfers Into/(Out of) Level 3		3	(4)
Ending balance at fair value		318	315
Fixed Income Securities [Member] | Corporate
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		19,603
Ending balance at fair value		17,481	19,603
Fixed Income Securities [Member] | Corporate | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value	[1]	2
Net Purchases, Issuances and Settlements	[1]
Net Transfers Into/(Out of) Level 3	[1]
Ending balance at fair value	[1]	2	2
Fixed Income Securities [Member] | US Treasury and Government [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		5,430
Ending balance at fair value		5,589	5,430
Fixed Income Securities [Member] | US Treasury and Government [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value
Ending balance at fair value
Fixed Income Securities [Member] | US Government Corporations and Agencies Securities [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value	[1]		1
Net Transfers Into/(Out of) Level 3	[1]		(1)
Fixed Income Securities [Member] | Mortgage backed, asset back, and other securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Ending balance at fair value		722
Fixed Income Securities [Member] | Mortgage backed, asset back, and other securities [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value	[1]	310
Net Realized and Unrealized Gains/(Losses)	[1]	(3)
Net Purchases, Issuances and Settlements	[1]	3
Net Transfers Into/(Out of) Level 3	[1]	2
Ending balance at fair value	[1]	312	310
Fixed Income Securities [Member] | Mortgage backed and asset backed
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		760
Ending balance at fair value			760
Fixed Income Securities [Member] | Mortgage backed and asset backed | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value	[1]	300	331
Net Realized and Unrealized Gains/(Losses)	[1]		10
Net Purchases, Issuances and Settlements	[1]		(39)
Net Transfers Into/(Out of) Level 3	[1]		(2)
Ending balance at fair value	[1]		300
Fixed Income Securities [Member] | Corporate and other [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value	[1]	12	12
Net Purchases, Issuances and Settlements	[1]		1
Net Transfers Into/(Out of) Level 3	[1]		(1)
Ending balance at fair value	[1]		12
Fixed Income Securities [Member] | Other Debt Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		118
Ending balance at fair value		106	118
Fixed Income Securities [Member] | Real assets [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Net Transfers Into/(Out of) Level 3	[1]	1
Equity securities [Member] | United States Common And Preferred Stock [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		4,615
Ending balance at fair value		3,744	4,615
Equity securities [Member] | United States Common And Preferred Stock [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value			1
Ending balance at fair value
Equity securities [Member] | Non United States Common And Preferred Stock [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		6,204
Ending balance at fair value		4,850	6,204
Real estate and real assets [Member] | Real assets [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		705
Ending balance at fair value		659	705
Real estate and real assets [Member] | Real assets [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		3	5
Net Purchases, Issuances and Settlements			(2)
Ending balance at fair value		$ 4	$ 3

[1] Certain fixed income securities were reclassified between mortgage backed and asset backed and corporate on January 1, 2018 and 2017.