REVENUES - Schedule of Changes in the Deferred Revenue Balances (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	$ 1,070.8	$ 986.5	$ 1,075.7	$ 946.3
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(454.6)	(444.4)	(878.2)	(804.7)
Increases due to amounts billable excluding amounts recognized as revenue during the period	372.1	353.5	788.2	768.9
Amount included in liabilities reclassified as held for sale			(2.7)
Effect of exchange rate changes	(17.6)	(0.2)	(12.3)	(15.1)
Total changes in deferred revenue	(100.1)	(91.1)	(105.0)	(50.9)
Ending Balance	970.7	895.4	970.7	895.4
Deferred revenue - current	855.7	771.5	855.7	771.5	$ 953.4
Deferred revenue - noncurrent	115.0	123.9	115.0	123.9	$ 122.3
MIS
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	376.0	377.5	325.4	334.7
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(110.8)	(127.4)	(190.8)	(196.2)
Increases due to amounts billable excluding amounts recognized as revenue during the period	82.0	101.6	211.6	217.6
Amount included in liabilities reclassified as held for sale			0.0
Effect of exchange rate changes	(3.7)	1.1	(2.7)	(3.3)
Total changes in deferred revenue	(32.5)	(24.7)	18.1	18.1
Ending Balance	343.5	352.8	343.5	352.8
Deferred revenue - current	233.2	233.9	233.2	233.9
Deferred revenue - noncurrent	110.3	118.9	110.3	118.9
MA
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	694.8	609.0	750.3	611.6
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(343.8)	(317.0)	(687.4)	(608.5)
Increases due to amounts billable excluding amounts recognized as revenue during the period	290.1	251.9	576.6	551.3
Amount included in liabilities reclassified as held for sale			(2.7)
Effect of exchange rate changes	(13.9)	(1.3)	(9.6)	(11.8)
Total changes in deferred revenue	(67.6)	(66.4)	(123.1)	(69.0)
Ending Balance	627.2	542.6	627.2	542.6
Deferred revenue - current	622.5	537.6	622.5	537.6
Deferred revenue - noncurrent	$ 4.7	$ 5.0	$ 4.7	$ 5.0