Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended		9 Months Ended		9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2013 VEBAs	Sep. 30, 2013 VEBAs Maximum	Sep. 30, 2013 Union VEBA trustrees	Sep. 30, 2013 Union VEBA Company Appointed trustrees	Sep. 30, 2013 Salaried VEBA	Mar. 31, 2013 Variable cash contribution VEBAs	Sep. 30, 2013 Variable cash contribution VEBAs Maximum	Sep. 30, 2013 Variable cash contribution VEBAs Annual Cash Flows up to $20 Million	Sep. 30, 2013 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%
Annual VEBA contribution paid						$ 20.0