v3.26.3
SEGMENTS - Geographic Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]      
Revenues $ 10,557 $ 8,831 $ 7,940
Long-Lived Asset, Excluding Financial Instrument, Customer Relationship, Mortgage Servicing Right, Deferred Policy Acquisition Cost, and Deferred Tax Asset, Amount 1,924 1,644 1,549
UNITED STATES      
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]      
Revenues 6,859 5,535 5,032
Long-Lived Asset, Excluding Financial Instrument, Customer Relationship, Mortgage Servicing Right, Deferred Policy Acquisition Cost, and Deferred Tax Asset, Amount 1,541 1,339 1,273
Non-US      
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]      
Revenues 3,698 3,296 2,908
Long-Lived Asset, Excluding Financial Instrument, Customer Relationship, Mortgage Servicing Right, Deferred Policy Acquisition Cost, and Deferred Tax Asset, Amount $ 383 $ 305 $ 276