Consolidated Statement of Earnings - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Commissions	$ 2,338.7	$ 2,083.0	$ 1,553.1
Fees	1,432.3	1,258.3	1,059.5
Supplemental commissions	125.5	104.0	77.3
Contingent commissions	93.7	84.7	52.1
Investment income	54.2	41.3	8.1
Gains on books of business sales	6.7	7.3	5.2
Revenues from clean coal activities	1,310.8	1,029.5	412.5
Other net revenues	30.5	18.4	11.8
Total revenues	5,392.4	4,626.5	3,179.6
Compensation	2,428.9	2,167.6	1,685.0
Operating	840.7	743.1	535.9
Cost of revenues from clean coal activities	1,351.5	1,058.9	437.3
Interest	103.0	89.0	50.1
Depreciation	93.9	69.4	53.4
Amortization	240.3	189.5	125.2
Change in estimated acquisition earnout payables	40.6	17.5	1.7
Total expenses	5,098.9	4,335.0	2,888.6
Earnings before income taxes	293.5	291.5	291.0
Provision (benefit) for income taxes	(95.6)	(36.0)	6.4
Net earnings	389.1	327.5	284.6
Net earnings attributable to noncontrolling interests	32.3	24.1	16.0
Net earnings attributable to controlling interests	$ 356.8	$ 303.4	$ 268.6
Basic net earnings per share:	$ 2.07	$ 1.98	$ 2.08
Diluted net earnings per share:	2.06	1.97	2.06
Dividends declared per common share	$ 1.48	$ 1.44	$ 1.40