Environmental and Legal Contingencies (Details 6) (USD $) In Millions, unless otherwise specified	1 Months Ended	0 Months Ended								0 Months Ended			0 Months Ended
	Oct. 31, 2009 Schumacher [Member] plaintiffs	Aug. 26, 2009 Consolidation Coal [Member]	Jul. 31, 2013 Final [Member] MOFCOM [Member]	Jul. 31, 2013 Final [Member] Countervailing Duty [Member] MOFCOM [Member]	Jul. 31, 2013 Final [Member] Antidumping Duty [Member] MOFCOM [Member]	Jul. 31, 2013 Preliminary [Member] Countervailing Duty [Member] MOFCOM [Member]	Oct. 14, 2013 Preliminary [Member] Attorneys [Member] Schumacher [Member]	Nov. 13, 2013 Final [Member] Schumacher [Member]	May 29, 2013 Final [Member] Schumacher [Member]	Nov. 23, 2013 Final [Member] Patrick [Member]	Nov. 23, 2013 Final [Member] Plaintiffs And Other Class Members [Member] Patrick [Member]	Oct. 14, 2013 Final [Member] Attorneys [Member] Schumacher [Member]	Nov. 23, 2013 Final [Member] Attorneys [Member] Patrick [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs	92
Potential exposure of increase to defined benefit plan obligation							$ 1.3	$ 4.4	$ 3.0			$ 0.6
Total Amount Paid in Settlements										2.5	1.7		0.8
Loss contingency, damages sought, value		30.0
Loss contingency, damages sought, value, codefendant		$ 20.0
Duty Rate			11.20%	3.40%	7.80%	11.70%