Employee Benefit Plans Weighted Average Discount Rate Used to Determine the Net Periodic Postretirement Benefit Costs (Details) (Other Postretirement Benefit Plans, Defined Benefit)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Net periodic postretirement benefit costs	4.00%	3.50%	3.75%
Accumulated postretirement benefit obligations	3.25%	4.00%	3.50%