Noncontrolling Interests in Consolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Summary financial statistics - statement of operations and cash flows, consolidated affiliates
Sales	$ 776.6	$ 864.2	$ 2,357.7	$ 2,386.3
Income (loss) before taxes	111.4	121.6	309.0	313.2
Net income (loss)	76.0	81.2	207.0	210.7
Noncontrolling interests in net income (loss)	0.5	(0.1)	1.3	(0.6)
Summary financial statistics - balance sheet information, consolidated affiliates
Other current assets	95.1		95.1		93.0
Total assets	4,756.5		4,756.5		4,494.0
Total liabilities	4,354.3		4,354.3		4,326.5
Shareholders' equity	402.2	75.7	402.2	75.7	167.5	(68.8)
Noncontrolling interests in shareholders' equity	9.4		9.4		8.1
Joint ventures
Summary financial statistics - statement of operations and cash flows, consolidated affiliates
Sales	25.3	22.5	77.0	62.6
Income (loss) before taxes	1.8	(0.9)	5.9	(2.4)
Net income (loss)	1.5	(1.0)	5.0	(2.7)
Noncontrolling interests in net income (loss)	0.5	(0.1)	1.3	(0.6)
Summary financial statistics - balance sheet information, consolidated affiliates
Cash	8.5		8.5		6.7
Other current assets	37.5		37.5		34.7
Total assets	60.2		60.2		53.0
Total liabilities	33.2		33.2		30.3
Shareholders' equity	27.0		27.0		22.7
Noncontrolling interests in shareholders' equity	$ 9.4		$ 9.4		$ 8.1