Environmental Obligations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Enviromental Liability Rollforward [Line Items]
Environmental reserves, excluding recoveries	$ 219.1				$ 219.1				$ 236.5
Environmental loss contingencies, net of expected recoveries, in excess of accrual					160
Accrual for Environmental Loss Contingencies [Roll Forward]
Total environmental reserves, net of recoveries at begining of period					216.0
Spending, net of recoveries					(27.9)
Net change					(17.6)
Total environmental reserves, net of recoveries at end of period	198.4				198.4
Accrual for Environmental Loss Contingencies, Increase (Decrease) for Revision in Estimates	5.0	[1]	9.4	[1]	10.3	[1]	14.5	[1]
Environmental reserves, current, net of recoveries (1)	24.4	[2]			24.4	[2]
Environmental reserves, long-term continuing and discontinued, net of recoveries	174.0	[3]			174.0	[3]			200.2
Expected recoveries recorded	66.3				66.3				72.1
Increase in Third-party Environmental Recoveries Receivable					2.7
Cash recoveries recorded					(8.5)
Total environmental reserves, net of recoveries at end of period	198.4				198.4
Environmental Charges, Net	4.2		9.4		8.5		14.5
Environmental Cost Recognized, Recovery Credited to Expense	(0.8)	[4]	0	[4]	(1.8)	[4]	0	[4]
Environmental Provision, Net of Recoveries recorded to Other Assets	4.2		9.4		8.5		14.5
Middleport [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Total environmental reserves, net of recoveries at begining of period									42.4
Total environmental reserves, net of recoveries at end of period	41.0				41.0				42.4
Total environmental reserves, net of recoveries at end of period	41.0				41.0				42.4
Environmental Liabilities, Continuing and Discontinued [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Expected recoveries recorded	20.7				20.7				20.5
Increase in Third-party Environmental Recoveries Receivable					0.9
Cash recoveries recorded					(0.7)
Other Assets [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Expected recoveries recorded	45.6				45.6				51.6
Increase in Third-party Environmental Recoveries Receivable					1.8
Cash recoveries recorded					(7.8)
Segment, Continuing Operations [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Environmental Charges, Net	1.0	[5]	1.5	[5]	2.0	[5]	2.5	[5]
Segment, Discontinued Operations [Member] | Environmental Remediation Expense [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Environmental Charges, Net	$ 3.2	[6]	$ 7.9	[6]	$ 6.5	[6]	$ 12.0	[6]

[1] See above roll forward of our total environmental reserves as presented on our condensed consolidated balance sheets.

[2] “Current” includes only those reserves related to continuing operations. These amounts are included within "Accrued and other liabilities" on the condensed consolidated balance sheets.

[3] These amounts are included in “Environmental liabilities, continuing and discontinued” on the condensed consolidated balance sheets.

[4] Represents certain environmental recoveries.

[5] Recorded as a component of “Restructuring and other charges (income)” on our condensed consolidated statements of income. See Note 7.

[6] Recorded as a component of “Discontinued operations, net of income taxes" on our consolidated statements of income. See Note 10.