Postretirement Benefits (Components Of Postretirement Benefit Expense) (Details) (U.S. Postretirement Benefit Plans [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
U.S. Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 2	$ 2
Interest cost	20	21	23
Actuarial loss	10	9	12
Amortization of prior service credits	(30)	(25)	(31)
Curtailments	(7)	0	0
Net periodic pension expense	$ (4)	$ 7	$ 6