Revenues - Consolidated Revenue Information by Geographic Area (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenue	$ 7,718	$ 7,088	$ 5,916
Operating Segments
Segment Reporting Information [Line Items]
Revenue	7,718	7,088	5,916
MA
Segment Reporting Information [Line Items]
Revenue	3,599	3,295	3,056
MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	3,611	3,308	3,069
MIS
Segment Reporting Information [Line Items]
Revenue	4,119	3,793	2,860
MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	4,317	3,986	3,046
U.S.
Segment Reporting Information [Line Items]
Revenue	4,171	3,836	3,071
U.S. | MA
Segment Reporting Information [Line Items]
Revenue	1,548	1,390	1,321
U.S. | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	1,548	1,390	1,321
U.S. | MIS
Segment Reporting Information [Line Items]
Revenue	2,623	2,446	1,750
U.S. | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	2,623	2,446	1,750
Non-U.S.
Segment Reporting Information [Line Items]
Revenue	3,547	3,252	2,845
Non-U.S. | MA
Segment Reporting Information [Line Items]
Revenue	2,051	1,905	1,735
Non-U.S. | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	2,051	1,905	1,735
Non-U.S. | MIS
Segment Reporting Information [Line Items]
Revenue	1,496	1,347	1,110
Non-U.S. | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	1,496	1,347	1,110
EMEA
Segment Reporting Information [Line Items]
Revenue	2,376	2,174	1,886
EMEA | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	1,406	1,306	1,207
EMEA | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	970	868	679
Asia-Pacific
Segment Reporting Information [Line Items]
Revenue	699	629	570
Asia-Pacific | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	374	345	299
Asia-Pacific | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	325	284	271
Americas
Segment Reporting Information [Line Items]
Revenue	472	449	389
Americas | MA | Operating Segments
Segment Reporting Information [Line Items]
Revenue	271	254	229
Americas | MIS | Operating Segments
Segment Reporting Information [Line Items]
Revenue	$ 201	$ 195	$ 160