Employee Benefit Plans (The Estimated Portion of Balances Remaining in Accumulated Other Comprehensive Income (Loss) that are Expected to be Recognized as a Component of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Net loss	$ 60
Transition obligation	4
Prior service cost (credit)	3
Pension Plans, Defined Benefit [Member] | Qualified Plans [Member]
Net loss	51
Transition obligation	0
Prior service cost (credit)	4
Pension Plans, Defined Benefit [Member] | Non Qualified Plans [Member]
Net loss	8
Transition obligation	0
Prior service cost (credit)	(2)
Postretirement Benefit Plan
Net loss	1
Transition obligation	4
Prior service cost (credit)	$ 1