Acquisitions and Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Acquisitions
Total cost	$ 2.0	$ 23.6	$ 2.0	$ 23.6
Net cash paid	0	15.3	0	15.3
Goodwill recorded	0.8	7.0	0.8	7.0
Divestitures
Proceeds	2.1	8.3	2.1	8.3
Gain recognized	1.5	0.7	1.5	0.7
Goodwill charged off	$ 0.1	$ 1.0	$ 0.1	$ 1.0