Consolidated Statement of Earnings - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues before reimbursements	$ 2,008.4	$ 1,896.8	$ 4,412.9	$ 4,029.4
Reimbursements	34.6	36.7	65.4	69.1
Total revenues	2,043.0	1,933.5	4,478.3	4,098.5
Compensation	1,161.1	937.1	2,443.1	1,912.7
Operating	323.9	253.4	641.2	486.5
Reimbursements	34.6	36.7	65.4	69.1
Cost of revenues from clean coal activities		268.8	22.9	577.9
Interest	64.6	56.2	128.5	104.3
Depreciation	40.0	37.2	75.2	75.3
Amortization	100.3	108.0	224.9	213.2
Change in estimated acquisition earnout payables	(33.8)	13.8	(12.9)	28.8
Total expenses	1,690.7	1,711.2	3,588.3	3,467.8
Earnings before income taxes	352.3	222.3	890.0	630.7
Provision for income taxes	67.2	20.5	165.8	35.2
Net earnings	285.1	201.8	724.2	595.5
Net earnings attributable to noncontrolling interests	0.9	11.6	1.3	23.2
Net earnings attributable to controlling interests	$ 284.2	$ 190.2	$ 722.9	$ 572.3
Basic net earnings per share	$ 1.35	$ 0.94	$ 3.45	$ 2.89
Diluted net earnings per share	1.33	0.92	3.38	2.83
Dividends declared per common share	$ 0.51	$ 0.48	$ 1.02	$ 0.96
Commissions [Member]
Revenues before reimbursements	$ 1,282.4	$ 977.1	$ 2,847.7	$ 2,102.5
Broker Fees [Member]
Revenues before reimbursements	590.9	540.9	1,241.8	1,094.7
Supplemental Revenue [Member]
Revenues before reimbursements	65.7	55.2	140.0	122.0
Contingent Revenue [Member]
Revenues before reimbursements	43.1	43.3	114.7	106.6
Investment Income [Member]
Revenues before reimbursements	23.2	18.1	41.4	35.2
Net Gains on Divestitures [Member]
Revenues before reimbursements	2.8	0.6	4.2	4.7
Clean Coal Activities [Member]
Revenues before reimbursements	$ 0.3	261.0	23.0	561.6
Other Net Revenue (Losses) [Member]
Revenues before reimbursements		$ 0.6	$ 0.1	$ 2.1