Contingent Acquisition Obligations (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Deferred acquisition payments
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	$ 60.3
Recorded Unconditional Purchase Obligation Due in Second Year	21.3
Recorded Unconditional Purchase Obligation Due in Third Year	49.1
Recorded Unconditional Purchase Obligation Due in Fourth Year	7.9
Recorded Unconditional Purchase Obligation Due in Fifth Year	10.8
Recorded Unconditional Purchase Obligation Due after Fifth Year	0.9
Recorded Unconditional Purchase Obligation	150.3
Redeemable noncontrolling interests and call options with affiliates
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	35.4
Recorded Unconditional Purchase Obligation Due in Second Year	65.0
Recorded Unconditional Purchase Obligation Due in Third Year	37.0
Recorded Unconditional Purchase Obligation Due in Fourth Year	7.8
Recorded Unconditional Purchase Obligation Due in Fifth Year	10.5
Recorded Unconditional Purchase Obligation Due after Fifth Year	7.0
Recorded Unconditional Purchase Obligation	162.7	[1]
Redeemable at noncontrolling equity owners discretion
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	20.5
Total contingent acquisition payments
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	95.7
Recorded Unconditional Purchase Obligation Due in Second Year	86.3
Recorded Unconditional Purchase Obligation Due in Third Year	86.1
Recorded Unconditional Purchase Obligation Due in Fourth Year	15.7
Recorded Unconditional Purchase Obligation Due in Fifth Year	21.3
Recorded Unconditional Purchase Obligation Due after Fifth Year	7.9
Recorded Unconditional Purchase Obligation	313.0
Cash compensation expense included in contingent acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	1.9
Recorded Unconditional Purchase Obligation Due in Second Year	1.6
Recorded Unconditional Purchase Obligation Due in Third Year	0.7
Recorded Unconditional Purchase Obligation Due in Fourth Year	0
Recorded Unconditional Purchase Obligation Due in Fifth Year	0
Recorded Unconditional Purchase Obligation Due after Fifth Year	0
Recorded Unconditional Purchase Obligation	4.2
Total contingent acquisition payments excluding compensation expense
Business Acquisition, Contingent Consideration [Line Items]
Recorded Unconditional Purchase Obligation Due in Next Twelve Months	93.8
Recorded Unconditional Purchase Obligation Due in Second Year	84.7
Recorded Unconditional Purchase Obligation Due in Third Year	85.4
Recorded Unconditional Purchase Obligation Due in Fourth Year	15.7
Recorded Unconditional Purchase Obligation Due in Fifth Year	21.3
Recorded Unconditional Purchase Obligation Due after Fifth Year	7.9
Recorded Unconditional Purchase Obligation	$ 308.8

[1] We have entered into certain acquisitions that contain both redeemable noncontrolling interests and call options with similar terms and conditions. The estimated amounts listed would be paid in the event of exercise at the earliest exercise date. We have certain redeemable noncontrolling interests that are exercisable at the discretion of the noncontrolling equity owners as of December 31, 2014. These estimated payments of $20.5 are included within the total payments expected to be made in 2015, and will continue to be carried forward into 2016 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.