Cash Paid for Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Business Combinations [Abstract]
Cost of investment: current year acquisitions	$ 32.3		$ 39.0
Cost of investment: prior-year acquisitions	3.3		0.7
Less: net cash acquired	(10.2)		(4.1)
Total cash paid for acquisitions	25.4	[1]	35.6	[1]
Acquisition-related payments	3.3		0.7
Acquisitions, including deferred payments, net of cash acquired	$ 22.1		$ 34.9

[1] Of the total cash paid, $3.3 and $0.7 for the three months ended March 31, 2014, and 2013, respectively, are classified under the financing section of the unaudited Consolidated Statements of Cash Flows within other financing activities. These amounts relate to increases in our ownership interests in our consolidated subsidiaries, as well as deferred payments for acquisitions that closed on or after January 1, 2009. Of the total cash paid, $22.1 and $34.9 for the three months ended March 31, 2014, and 2013, respectively, are classified under the investing section of the unaudited Consolidated Statements of Cash Flows within acquisitions, including deferred payments, net of cash acquired. These amounts relate to initial payments for new transactions and deferred payments for acquisitions that closed prior to January 1, 2009.