Acquisition (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Business Acquisition [Line Items]
Total revenues	$ 2,166.7	$ 2,095.9
Net income (loss)	190.0	221.3
Cuprum
Business Acquisition [Line Items]
Total revenues	18.3
Net income (loss)	$ 9.3