Postretirement Plans (Schedule Of Changes In Fair Value Of Level 3 Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Postretirement Plans [Line Items]
Beginning Balance	$ 3,400	$ 2,663
Realized gains, net	194	126
Unrealized gains, net	9	123
Purchases, sales, and settlements, net	(72)	487
Transfers into (out of) Level 3	23	1
Ending Balance	3,554	3,400
Private Equity Funds [Member]
Postretirement Plans [Line Items]
Beginning Balance	2,085	1,730
Realized gains, net	171	123
Unrealized gains, net	7	103
Purchases, sales, and settlements, net	23	129
Ending Balance	2,286	2,085
Real Estate Funds [Member]
Postretirement Plans [Line Items]
Beginning Balance	164	125
Realized gains, net	25
Unrealized gains, net	22	7
Purchases, sales, and settlements, net	67	32
Ending Balance	278	164
Hedge Funds [Member]
Postretirement Plans [Line Items]
Beginning Balance	1,025	750
Realized gains, net	(4)	1
Unrealized gains, net	(11)	13
Purchases, sales, and settlements, net	(183)	261
Transfers into (out of) Level 3	(2)
Ending Balance	825	1,025
Other [Member]
Postretirement Plans [Line Items]
Beginning Balance	126	58
Realized gains, net	2	2
Unrealized gains, net	(9)
Purchases, sales, and settlements, net	21	65
Transfers into (out of) Level 3	25	1
Ending Balance	$ 165	$ 126