Postretirement Plans (Reconciliation Of Level 3 Assets Held) (Details) - Pension Plans [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		$ 61,119		$ 58,131
Net Realized and Unrealized Gains/(Losses)		(701)		5,893
Net Purchases, Issuances and Settlements		(649)		(640)
Ending balance at fair value		56,514		61,119
Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		621		577
Net Realized and Unrealized Gains/(Losses)		(12)		14
Net Purchases, Issuances and Settlements		(153)		6
Net Transfers Into/(Out of) Level 3		8		24
Ending balance at fair value		464		621
Fixed Income Securities [Member] | Corporate [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Ending balance at fair value		16,339
Fixed Income Securities [Member] | Corporate [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 Purchases, Issuances and Settlements		1
Net Transfers Into/(Out of) Level 3		1
Ending balance at fair value		3		1	[1]
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		5,224
Ending balance at fair value		4,801		5,224
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	[1]	1
Ending balance at fair value		1		1	[1]
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		1,207
Ending balance at fair value		830		1,207
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		611	[1]	554	[2]
Net Realized and Unrealized Gains/(Losses)		(9)		14
Net Purchases, Issuances and Settlements		(157)		10
Net Transfers Into/(Out of) Level 3		3		33
Ending balance at fair value		448		611	[1]
Fixed Income Securities [Member] | Corporate and other [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		17,488
Ending balance at fair value				17,488
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		2		19	[2]
Net Purchases, Issuances and Settlements				(7)
Net Transfers Into/(Out of) Level 3				(10)
Ending balance at fair value				2
Fixed Income Securities [Member] | Other [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		246
Ending balance at fair value		83		246
Fixed Income Securities [Member] | Other [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Net Realized and Unrealized Gains/(Losses)		(3)
Net Purchases, Issuances and Settlements		$ 3
Ending balance at fair value
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		$ 7,605
Ending balance at fair value		5,165		7,605
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]
Net Transfers Into/(Out of) Level 3		1
Ending balance at fair value		1
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		7,151
Ending balance at fair value		5,712		7,151
Equity securities [Member] | Non 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		1
Net Purchases, Issuances and Settlements		(2)		(1)
Net Transfers Into/(Out of) Level 3		3		1
Ending balance at fair value		2		1
Private Equity Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance at fair value		3
Ending balance at fair value		3		3
Private Equity Funds [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		3
Ending balance at fair value		3		3
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		743
Ending balance at fair value		632		743
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		4
Net Purchases, Issuances and Settlements		2		4
Ending balance at fair value		$ 6		$ 4

[1] Certain fixed income securities were reclassified from corporate and mortgage backed and asset backed to U.S. government and agencies on January 1, 2015.

[2] Certain fixed income securities were reclassified from corporate to mortgage backed and asset backed on January 1, 2014.