v3.26.1
REVENUES - Revenue by Category (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenue $ 2,185 $ 1,898 $ 4,264 $ 3,822
Eliminations        
Disaggregation of Revenue [Line Items]        
Revenue (55) (53) (109) (105)
Eliminations        
Disaggregation of Revenue [Line Items]        
Revenue (55) (53) (109) (105)
MA        
Disaggregation of Revenue [Line Items]        
Revenue 925 888 1,851 1,747
MA | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 928 891 1,857 1,753
MA | Eliminations        
Disaggregation of Revenue [Line Items]        
Revenue 3 3 6 6
MA | Decision Solutions (DS) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 423 413 855 818
MA | Decision Solutions (DS) | Banking | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 119 138 252 279
MA | Decision Solutions (DS) | Insurance | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 183 168 364 331
MA | Decision Solutions (DS) | KYC | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 121 107 239 208
MA | Research and Insights (R&I) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 256 249 511 485
MA | Data and Information (D&I) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 246 226 485 444
MIS        
Disaggregation of Revenue [Line Items]        
Revenue 1,260 1,010 2,413 2,075
MIS | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 1,312 1,060 2,516 2,174
MIS | Eliminations        
Disaggregation of Revenue [Line Items]        
Revenue 52 50 103 99
MIS | Corporate Finance (CFG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 651 512 1,284 1,076
MIS | Corporate Finance (CFG) | Investment-grade | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 186 142 406 307
MIS | Corporate Finance (CFG) | High-yield | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 113 85 201 152
MIS | Corporate Finance (CFG) | Bank loans | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 147 98 286 258
MIS | Corporate Finance (CFG) | Other accounts | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 205 187 391 359
MIS | Structured Finance (SFG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 151 135 288 273
MIS | Structured Finance (SFG) | Other accounts | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 1 0 2 1
MIS | Structured Finance (SFG) | Asset-backed securities | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 45 35 83 70
MIS | Structured Finance (SFG) | RMBS | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 35 29 67 55
MIS | Structured Finance (SFG) | CMBS | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 25 25 47 53
MIS | Structured Finance (SFG) | Structured credit | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 45 46 89 94
MIS | Financial Institutions (FIG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 222 191 416 382
MIS | Financial Institutions (FIG) | Insurance | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 47 54 85 99
MIS | Financial Institutions (FIG) | Other accounts | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 4 4 8 7
MIS | Financial Institutions (FIG) | Banking | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 148 120 282 250
MIS | Financial Institutions (FIG) | Managed investments | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 23 13 41 26
MIS | Public, Project and Infrastructure Finance (PPIF) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 224 162 400 325
MIS | Public, Project and Infrastructure Finance (PPIF) | Public finance / sovereign | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 82 75 156 147
MIS | Public, Project and Infrastructure Finance (PPIF) | Project and infrastructure | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 142 87 244 178
MIS | Total ratings revenue        
Disaggregation of Revenue [Line Items]        
Revenue 1,248 1,000    
MIS | Total ratings revenue | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 1,248 1,000 2,388 2,056
MIS | MIS Other        
Disaggregation of Revenue [Line Items]        
Revenue 12 10    
MIS | MIS Other | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue $ 12 $ 10 $ 25 $ 19