Other income expense Other income expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2008	Jun. 30, 2012 Spark Plug Business [Member]	Sep. 30, 2012 Spark Plug Business [Member]
Significant Acquisitions and Disposals [Line Items]
Loss from disposal activities	$ 1.8	$ 0	$ 39.7	$ 0		$ 37.9
Restructuring Charges	27.4	0	27.4	0
Gain (Loss) Related to Litigation Settlement	0	0	0	(29.1)	4.0
Other Operating Income				(0.8)
Other Cost and Expense, Operating	0.5	0.6	0.3
Other Operating Income (Expense), Net	(29.7)	(0.6)	(67.4)	29.9
Proceeds from sale of business			56.8	2.1			55.2
Severance Costs	16.9
Other Restructuring Costs	10.5
Litigation Settlement, Gross				32.5
Litigation Settlement, Expense				$ 3.4