Revenues - Consolidated Revenue Information by Geographic Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenue	$ 1,472	$ 1,275	$ 4,436	$ 4,178
MA
Segment Reporting Information [Line Items]
Revenue	776	685	2,260	2,055
MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	779	687	2,270	2,060
MIS
Segment Reporting Information [Line Items]
Revenue	696	590	2,176	2,123
MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	743	633	2,314	2,252
United States
Segment Reporting Information [Line Items]
Revenue	768	668	2,320	2,214
United States | MA
Segment Reporting Information [Line Items]
Revenue	340	306	991	913
United States | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	340	306	991	913
United States | MIS
Segment Reporting Information [Line Items]
Revenue	428	362	1,329	1,301
United States | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	428	362	1,329	1,301
Non-U.S.
Segment Reporting Information [Line Items]
Revenue	704	607	2,116	1,964
Non-U.S. | MA
Segment Reporting Information [Line Items]
Revenue	436	379	1,269	1,142
Non-U.S. | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	436	379	1,269	1,142
Non-U.S. | MIS
Segment Reporting Information [Line Items]
Revenue	268	228	847	822
Non-U.S. | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	268	228	847	822
EMEA
Segment Reporting Information [Line Items]
Revenue	455	393	1,376	1,271
EMEA | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	300	254	867	774
EMEA | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	155	139	509	497
Asia-Pacific
Segment Reporting Information [Line Items]
Revenue	145	129	442	422
Asia-Pacific | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	78	72	229	211
Asia-Pacific | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	67	57	213	211
Americas
Segment Reporting Information [Line Items]
Revenue	104	85	298	271
Americas | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	58	53	173	157
Americas | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	$ 46	$ 32	$ 125	$ 114