Revenues - Revenue Recognition Timing (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 1,290	$ 1,142
At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	558	440
Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	732	702
MIS
Disaggregation of Revenue [Line Items]
Revenue recognized	794	670
MIS | At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	519	410
MIS | Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	275	260
MA
Disaggregation of Revenue [Line Items]
Revenue recognized	496	472
MA | At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	39	30
MA | Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 457	$ 442