Revenues - Schedule of Changes in the Deferred Revenue Balances (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	$ 1,162	$ 1,076
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(435)	(400)
Increases due to amounts billable excluding amounts recognized as revenue during the period	504	502
Increases due to RDC acquisition during the period	20
Effect of exchange rate changes	(29)	5
Total changes in deferred revenue	60	107
Ending Balance	1,222	1,183
Deferred revenue - current	1,113	1,062	$ 1,050
Deferred revenue - noncurrent	109	121	$ 112
MIS
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	322	326
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(99)	(93)
Increases due to amounts billable excluding amounts recognized as revenue during the period	161	155
Increases due to RDC acquisition during the period	0
Effect of exchange rate changes	(5)	0
Total changes in deferred revenue	57	62
Ending Balance	379	388
Deferred revenue - current	275	271
Deferred revenue - noncurrent	104	117
MA
Change in Contract with Customer, Liability [Abstract]
Beginning Balance	840	750
Revenue recognized that was included in the deferred revenue balance at the beginning of the period	(336)	(307)
Increases due to amounts billable excluding amounts recognized as revenue during the period	343	347
Increases due to RDC acquisition during the period	20
Effect of exchange rate changes	(24)	5
Total changes in deferred revenue	3	45
Ending Balance	843	795
Deferred revenue - current	838	791
Deferred revenue - noncurrent	$ 5	$ 4