Segment Reporting - Reconciliations Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 689.8	$ 625.0
Expenses:
Cost of revenues (exclusive of items shown separately below)	(257.7)	(231.4)
Selling, general and administrative	(112.1)	(111.4)
Other operating income	19.4	0.0
Investment (loss) income and others, net	(2.1)	(0.4)
EBITDA	337.3	281.8
Depreciation and amortization of fixed assets	(46.1)	(46.6)
Amortization of intangible assets	(41.0)	(33.2)
Interest expense	(33.5)	(31.9)
Income before income taxes	216.7	170.1
Insurance
Segment Reporting Information [Line Items]
Revenues	489.4	453.6
Expenses:
Cost of revenues (exclusive of items shown separately below)	(163.3)	(152.7)
Selling, general and administrative	(68.4)	(69.7)
Other operating income	15.9	0.0
Investment (loss) income and others, net	(1.2)	0.1
EBITDA	272.4	231.3
Energy and Specialized Markets
Segment Reporting Information [Line Items]
Revenues	160.1	128.4
Expenses:
Cost of revenues (exclusive of items shown separately below)	(70.5)	(54.4)
Selling, general and administrative	(38.9)	(36.3)
Other operating income	0.0	0.0
Investment (loss) income and others, net	(0.5)	(0.5)
EBITDA	50.2	37.2
Financial Services
Segment Reporting Information [Line Items]
Revenues	40.3	43.0
Expenses:
Cost of revenues (exclusive of items shown separately below)	(23.9)	(24.3)
Selling, general and administrative	(4.8)	(5.4)
Other operating income	3.5	0.0
Investment (loss) income and others, net	(0.4)	0.0
EBITDA	$ 14.7	$ 13.3