Contingent Acquisition Obligations (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Deferred acquisition payments
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	$ 26.0
Recorded Unconditional Purchase Obligation Due in Second Year	12.4
Recorded Unconditional Purchase Obligation Due in Third Year	9.7
Recorded Unconditional Purchase Obligation Due in Fourth Year	46.4
Recorded Unconditional Purchase Obligation Due in Fifth Year	18.9
Recorded Unconditional Purchase Obligation Due after Fifth Year	2.0
Recorded Unconditional Purchase Obligation	115.4
Redeemable noncontrolling interests and call options with affiliates
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	20.5
Recorded Unconditional Purchase Obligation Due in Second Year	43.8
Recorded Unconditional Purchase Obligation Due in Third Year	32.9
Recorded Unconditional Purchase Obligation Due in Fourth Year	5.7
Recorded Unconditional Purchase Obligation Due in Fifth Year	2.2
Recorded Unconditional Purchase Obligation Due after Fifth Year	10.6
Recorded Unconditional Purchase Obligation	115.7	[1]
Redeemable at noncontrolling equity owners discretion
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	16.4
Total contingent acquisition payments
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	46.5
Recorded Unconditional Purchase Obligation Due in Second Year	56.2
Recorded Unconditional Purchase Obligation Due in Third Year	42.6
Recorded Unconditional Purchase Obligation Due in Fourth Year	52.1
Recorded Unconditional Purchase Obligation Due in Fifth Year	21.1
Recorded Unconditional Purchase Obligation Due after Fifth Year	12.6
Recorded Unconditional Purchase Obligation	231.1
Cash compensation expense included in contingent acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	(0.7)
Recorded Unconditional Purchase Obligation Due in Second Year	(0.6)
Recorded Unconditional Purchase Obligation Due in Third Year	(0.8)
Recorded Unconditional Purchase Obligation Due in Fourth Year	(0.2)
Recorded Unconditional Purchase Obligation Due in Fifth Year	0
Recorded Unconditional Purchase Obligation Due after Fifth Year	0
Recorded Unconditional Purchase Obligation	(2.3)
Total contingent acquisition payments excluding compensation expense
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	45.8
Recorded Unconditional Purchase Obligation Due in Second Year	55.6
Recorded Unconditional Purchase Obligation Due in Third Year	41.8
Recorded Unconditional Purchase Obligation Due in Fourth Year	51.9
Recorded Unconditional Purchase Obligation Due in Fifth Year	21.1
Recorded Unconditional Purchase Obligation Due after Fifth Year	12.6
Recorded Unconditional Purchase Obligation	$ 228.8

[1] We have entered into certain acquisitions that contain both redeemable noncontrolling interests and call options with similar terms and conditions. We have certain redeemable noncontrolling interests that are exercisable at the discretion of the noncontrolling equity owners as of December 31, 2012. These estimated payments of $16.4 are included within the total payments expected to be made in 2013, and will continue to be carried forward into 2014 or beyond until exercised or expired. Redeemable noncontrolling interests are included in the table at current exercise price payable in cash, not at applicable redemption value in accordance with the authoritative guidance for classification and measurement of redeemable securities.