Revenues - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
MIS
Disaggregation of Revenue [Line Items]
Unbilled Receivables	$ 425	$ 361
MA
Disaggregation of Revenue [Line Items]
Unbilled Receivables	$ 128	$ 98

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration