Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, unless otherwise specified			6 Months Ended		6 Months Ended			6 Months Ended				6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 VEBAs	Jun. 30, 2014 VEBAs Maximum	Jun. 30, 2014 Union VEBA trustrees	Jun. 30, 2014 Union VEBA Company Appointed trustrees	Jun. 30, 2014 Union VEBA USW Appointed trustrees	Jun. 30, 2014 Salaried VEBA	Dec. 31, 2013 Variable cash contribution VEBAs	Dec. 31, 2012 Variable cash contribution VEBAs	Jun. 30, 2014 Variable cash contribution VEBAs Maximum	Jun. 30, 2014 Variable cash contribution VEBAs Annual Cash Flows up to $20 Million	Jun. 30, 2014 Variable cash contribution VEBAs Annual Cash Flows in Excess of $20 Million
VEBA Postretirement Medical Obligations
Number of trustees					4	2	2
Administrative expenses of the VEBAs				$ 0.3
Postretirement medical plan contribution obligation percentage												10.00%	20.00%
Cash flow in determining VEBA obligation			20.0
Variable cash contribution obligation to VEBAs											20.0
Percent allocation of total contribution between VEBAs					85.50%			14.50%
Annual variable cash contribution	$ 0	$ 16.0							$ 16.0	$ 20.0