Income Tax Matters, Components of Deferred Tax Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Deferred income tax assets:
Loss and credit carryforwards	$ 321.8		$ 342.2
VEBAs (See Note 7)	6.1		7.6
Other assets	34.4		35.3
Inventories and other	2.5		1.7
Valuation allowances	(19.9)		(18.7)
Total deferred income tax assets	344.9		368.1
Deferred income tax liabilities:
Property, plant, and equipment	(73.0)		(69.7)
VEBAs (See Note 7)	(152.4)		(136.9)
Inventories	(14.9)		0
Total deferred income tax liabilities	(240.3)		(206.6)
Net deferred income tax assets	104.6	[1]	161.5	[1]
Net deferred income tax assets, current	36.7		59.5
Net deferred income tax assets, long term	69.1		102.0
Deferred tax liability, long term	$ (1.2)

[1] Of the total net deferred income tax assets of $104.6, $36.7 was included in Prepaid expenses and other current assets, $69.1 was presented as Deferred tax assets, net and $1.2 was presented as Deferred tax liability on the Consolidated Balance Sheet as of December 31, 2013. Of the total net deferred income tax assets of $161.5, $59.5 was included in Prepaid expenses and other current assets and $102.0 was presented as Deferred tax assets, net on the Consolidated Balance Sheet as of December 31, 2012.