Pension And Other Postretirement Benefits (Schedule Of Changes In Benefit Obligations And Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Change in Benefit Obligation
Benefit obligation at end of year	$ 2,000		$ 1,900
Change in Plan Assets
Fair value of plan assets at end of year	1,975		1,907
Pension Benefits [Member]
Change in Benefit Obligation
Benefit obligation at beginning of year	1,970		1,796
Service cost	35		35		36
Interest cost	107		110		111
Amendments	18		(7)
Actuarial loss (gain)	176	[1]	179	[1]
Benefits paid	(182)		(146)
Termination benefits			3
Benefit obligation at end of year	2,124		1,970		1,796
Change in Plan Assets
Fair value of plan assets at beginning of year	1,632		1,500
Actual return on plan assets	127		173
Company contributions	117	[1]	105	[1]
Benefits paid	(182)		(146)
Fair value of plan assets at end of year	1,694		1,632		1,500
Funded Status at end of year (plan assets less plan obligations)	(430)		(338)
Other Postretirement Benefits [Member]
Change in Benefit Obligation
Benefit obligation at beginning of year	704		651
Service cost	5		5		7
Interest cost	37		39		40
Amendments	7
Actuarial loss (gain)	36	[1]	42	[1]
Benefits paid	(40)		(39)
Termination benefits	1		6
Benefit obligation at end of year	750		704		651
Change in Plan Assets
Fair value of plan assets at beginning of year	275		242
Actual return on plan assets			26
Company contributions	46	[1]	46	[1]
Benefits paid	(40)		(39)
Fair value of plan assets at end of year	281		275		242
Funded Status at end of year (plan assets less plan obligations)	$ (469)		$ (429)

[1] Other Postretirement Benefits paid is net of Medicare Part D subsidy receipts of $2 million in 2011 and $3 million in 2010.