Benefit Plans (Schedule Of Components Of Net Periodic Pension Cost) (Details) (Pension [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 79	$ 74	$ 80
Interest cost	344	351	356
Expected return on plan assets	(442)	(422)	(421)
Amortization of net loss	224	171	126
Amortization of Prior service cost	(10)	(14)	(13)
Termination, settlement and curtailment	21	41	0
Net periodic benefit costs	$ 236	$ 229	$ 154