Revenues - Revenue Recognition Timing (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 1,526	$ 1,356	$ 4,679	$ 4,081
At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	660	578	2,140	1,820
Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	866	778	2,539	2,261
MIS
Disaggregation of Revenue [Line Items]
Revenue recognized	925	825	2,941	2,557
MIS | At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	631	548	2,062	1,731
MIS | Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	294	277	879	826
MA
Disaggregation of Revenue [Line Items]
Revenue recognized	601	531	1,738	1,524
MA | At Point in Time
Disaggregation of Revenue [Line Items]
Revenue recognized	29	30	78	89
MA | Over Time
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 572	$ 501	$ 1,660	$ 1,435