Employee Benefit Plans Employee Benefit Plans (Details Textuals) (USD $)	6 Months Ended
	Jun. 30, 2012	Apr. 30, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	7.30%
Defined Contribution Plan Non Elective Contribution Percent	2.00%
Defined Contribution Plan Contribution Match Percent	50.00%
Defined Contribution Plan employee contribution percent	up to 6.00%
Defined contribution plan non elective contribution earings threshold less than amount			110,000
Defined Contribution Plan Non Elective Contribution Above Threshold Percent			0.50%
Defined Contribution Plan Non Elective Contribution Below Threshold Percent			1.50%
Defined contribution plan non elective contribution earnings threshold more than amount			0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Change in pension benefit obligation due to defined benefit plans remeasurement		117,000,000
Change in accumulated other comprehensive income due to defined benefit plan remeasurement		76,000,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.50%	4.75%
Defined benefit plan recognized net gain loss due to curtailments, net of tax	7,000,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Change in pension benefit obligation due to defined benefit plans remeasurement		111,000,000
Change in accumulated other comprehensive income due to defined benefit plan remeasurement		72,000,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.00%	4.50%
Defined benefit plan recognized net gain loss due to curtailments, net of tax	$ 1,000,000