Pension And Other Postretirement Benefits (Schedule Of Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 47	$ 41
Interest cost	160	169
Expected return on plan assets	(202)	(201)
Amortization of prior service cost (benefit)	5	5
Recognized net actuarial loss	96	62
Net periodic benefit cost	106	76
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4
Interest cost	33	40
Expected return on plan assets		(1)
Amortization of prior service cost (benefit)	(4)	(4)
Recognized net actuarial loss	6	7
Net periodic benefit cost	$ 39	$ 46