Pension And Other Postretirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 94	$ 116	$ 149
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	35	35	36
Interest cost	107	110	111
Expected return on plan assets	(128)	(117)	(101)
Amortization of net actuarial loss	47	42	56
Recognition of benefit contract			1
Plan amendments		1
Termination benefits		3
Net periodic benefit cost	61	74	103
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5	7
Interest cost	37	39	40
Expected return on plan assets	(19)	(16)	(13)
Amortization of prior service cost	(5)	(5)	(4)
Amortization of net actuarial loss	14	13	16
Termination benefits	1	6
Net periodic benefit cost	$ 33	$ 42	$ 46