Business Segment Information (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue and property, plant and equipment by geographical area
Total revenue	$ 517.3	$ 447.8	$ 420.7	$ 405.6	$ 475.1	$ 418.4	$ 401.2	$ 357.0	$ 1,791.4	$ 1,651.7	$ 1,304.9
Total property, plant and equipment, net	283.6				249.0				283.6	249.0
United States
Revenue and property, plant and equipment by geographical area
Total revenue									377.4	309.2	264.0
Total property, plant and equipment, net	53.7				44.9				53.7	44.9
Germany
Revenue and property, plant and equipment by geographical area
Total revenue									174.8	195.3	181.6
Total property, plant and equipment, net	155.3				132.2				155.3	132.2
Rest of Europe
Revenue and property, plant and equipment by geographical area
Total revenue									531.2	483.2	384.1
Total property, plant and equipment, net	63.5				60.3				63.5	60.3
Asia Pacific
Revenue and property, plant and equipment by geographical area
Total revenue									570.6	500.7	342.7
Total property, plant and equipment, net	6.0				7.3				6.0	7.3
Other
Revenue and property, plant and equipment by geographical area
Total revenue									137.4	163.3	132.5
Total property, plant and equipment, net	$ 5.1				$ 4.3				$ 5.1	$ 4.3