v3.25.2
AVAILABLE-FOR-SALE SECURITIES, Gross Unrealized Losses and Fair Value and Significant Assumptions (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Sep. 30, 2024
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months $ 114 $ 515
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 6,071 7,311
Unrealized losses 12 months or more (599) (653)
Fair value 6,185 7,826
Unrealized losses (599) (653)
Agency residential MBS    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 82 0
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 3,138 3,679
Unrealized losses 12 months or more (299) (327)
Fair value 3,220 3,679
Unrealized losses (299) (327)
Agency commercial MBS    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 5 0
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 1,176 1,287
Unrealized losses 12 months or more (98) (119)
Fair value 1,181 1,287
Unrealized losses (98) (119)
Agency CMOs    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 8 30
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 996 1,114
Unrealized losses 12 months or more (161) (170)
Fair value 1,004 1,144
Unrealized losses (161) (170)
U.S. Treasuries    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 0 475
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 11 229
Unrealized losses 12 months or more 0 (2)
Fair value 11 704
Unrealized losses 0 (2)
Other agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 0 10
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 342 539
Unrealized losses 12 months or more (3) (6)
Fair value 342 549
Unrealized losses (3) (6)
Non-agency residential MBS    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 14 0
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 383 417
Unrealized losses 12 months or more (37) (27)
Fair value 397 417
Unrealized losses (37) (27)
Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 4 0
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 21 42
Unrealized losses 12 months or more 0 (2)
Fair value 25 42
Unrealized losses 0 (2)
Other investments    
Debt Securities, Available-for-sale [Line Items]    
Fair value less than 12 months 1 0
Unrealized losses less than 12 months 0 0
Fair value 12 months or more 4 4
Unrealized losses 12 months or more (1) 0
Fair value 5 4
Unrealized losses $ (1) $ 0