Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2012 Air Quality [Member]	Dec. 31, 2012 Air Quality [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Amount of Other Income (Loss) from Disposition of Discontinued Operations, before Income Tax					$ 116.7
Discontinued Operation, Amount of Other Income (Loss) from Disposition of Discontinued Operation, Net of Tax				75.0	75.0
Impairment of Long-Lived Assets to be Disposed of	26.9				108.9
Impairment of Long-Lived Assets to be Disposed of (after tax)					68.8
Total revenues	229.1	200.1	277.5
Loss from Discontinued operations before income taxes	(163.9)	(88.8)	(30.2)
Income tax benefit	59.7	22.3	7.4
Loss from discontinued operations, net of income taxes	(104.2)	(66.5)	(22.8)
Other current assets	37.5	24.6
Investments and other assets	140.8	232.2
Total assets classified as discontinued operations	178.3	256.8
Accounts payable and accrued expenses	33.3	63.9
Other noncurrent liabilities	27.1	59.6
Total liabilities classified as discontinued operations	$ 60.4	$ 123.5