Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		3 Months Ended		3 Months Ended				3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 VEBAs	Mar. 31, 2014 VEBAs Maximum	Mar. 31, 2014 Union VEBA trustrees	Mar. 31, 2014 Union VEBA Company Appointed trustrees	Mar. 31, 2014 Salaried VEBA	Dec. 31, 2013 Variable cash contribution VEBAs	Dec. 31, 2012 Variable cash contribution VEBAs	Mar. 31, 2014 Variable cash contribution VEBAs Maximum	Mar. 31, 2014 Variable cash contribution VEBAs Annual Cash Flows up to $20 Million	Mar. 31, 2014 Variable cash contribution VEBAs Annual Cash Flows in Excess of $20 Million
VEBA Postretirement Medical Obligations
Number of trustees					4	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%
Accrued Annual Veba Contribution	$ 0	$ 16.0						$ 16.0	$ 20.0