Postretirement Plans (Reconciliation Of Level 3 Assets Held) (Details) (Pension Plans [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	$ 51,051	$ 49,252
Net Realized and Unrealized Gains/(Losses)	6,300	3,953
Net Purchases, Issuances and Settlements	(71)	(104)
Ending balance at fair value	56,178	51,051
Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	7,777	6,468
Net Realized and Unrealized Gains/(Losses)	519	529
Net Purchases, Issuances and Settlements	310	778
Net Transfers Into/(Out of) Level 3	(861)	2
Ending balance at fair value	7,745	7,777
Corporate [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	11	4
Net Realized and Unrealized Gains/(Losses)	(12)
Net Purchases, Issuances and Settlements	11	6
Net Transfers Into/(Out of) Level 3	(7)	1
Ending balance at fair value	3	11
Mortgage Backed And Asset Backed [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	11	33
Net Realized and Unrealized Gains/(Losses)	41	2
Net Purchases, Issuances and Settlements	151	(25)
Net Transfers Into/(Out of) Level 3	358	1
Ending balance at fair value	561	11
Municipal Bonds [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	3
Net Purchases, Issuances and Settlements		3
Net Transfers Into/(Out of) Level 3	(3)
Ending balance at fair value		3
Private equity [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	2,859	2,626
Net Realized and Unrealized Gains/(Losses)	208	327
Net Purchases, Issuances and Settlements	(151)	(94)
Ending balance at fair value	2,916	2,859
Real Estate [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	1,820	1,428
Net Realized and Unrealized Gains/(Losses)	133	179
Net Purchases, Issuances and Settlements	175	213
Ending balance at fair value	2,128	1,820
Real assets [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	547	390
Net Realized and Unrealized Gains/(Losses)	45	67
Net Purchases, Issuances and Settlements	72	90
Ending balance at fair value	664	547
Global strategies [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	75	69
Net Realized and Unrealized Gains/(Losses)		6
Net Transfers Into/(Out of) Level 3	(75)
Ending balance at fair value		75
Hedge funds [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance at fair value	2,451	1,918
Net Realized and Unrealized Gains/(Losses)	104	(52)
Net Purchases, Issuances and Settlements	52	585
Net Transfers Into/(Out of) Level 3	(1,134)
Ending balance at fair value	$ 1,473	$ 2,451