v3.26.1
INVESTMENT SECURITIES (Summary of Investment Securities) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Amortized cost    
Available-for-sale $ 10,383 $ 10,353
Held-to-maturity 8,688 8,867
Total investment securities 19,071 19,220
Gross unrealized gains    
Available-for-sale 12 22
Held-to-maturity 73 111
Total investment securities 85 133
Gross unrealized losses    
Available-for-sale 1,211 1,168
Held-to-maturity 65 38
Estimated fair value    
Available-for-sale 9,184 9,207
Held-to-maturity, Estimated fair value 8,696 8,940
Total investment securities 17,880 18,147
Total investment securities 1,276 1,206
U.S. Treasury securities    
Amortized cost    
Available-for-sale 1,799 1,500
Gross unrealized gains    
Available-for-sale 8 17
Gross unrealized losses    
Available-for-sale 116 106
Estimated fair value    
Available-for-sale 1,691 1,411
Agency securities    
Amortized cost    
Available-for-sale 294 313
Held-to-maturity 134 137
Gross unrealized gains    
Available-for-sale 0 0
Held-to-maturity 0 0
Gross unrealized losses    
Available-for-sale 16 15
Held-to-maturity 3 3
Estimated fair value    
Available-for-sale 278 298
Held-to-maturity, Estimated fair value 131 134
Agency guaranteed mortgage-backed securities    
Amortized cost    
Available-for-sale 7,017 7,207
Held-to-maturity 8,296 8,459
Gross unrealized gains    
Available-for-sale 4 5
Held-to-maturity 73 111
Gross unrealized losses    
Available-for-sale 1,012 989
Held-to-maturity 52 25
Estimated fair value    
Available-for-sale 6,009 6,223
Held-to-maturity, Estimated fair value 8,317 8,545
Small Business Administration loan-backed securities    
Amortized cost    
Available-for-sale 327 355
Gross unrealized gains    
Available-for-sale 0 0
Gross unrealized losses    
Available-for-sale 14 14
Estimated fair value    
Available-for-sale 313 341
Municipal securities    
Amortized cost    
Available-for-sale 921 953
Held-to-maturity 258 271
Gross unrealized gains    
Available-for-sale 0 0
Held-to-maturity 0 0
Gross unrealized losses    
Available-for-sale 52 44
Held-to-maturity 10 10
Estimated fair value    
Available-for-sale 869 909
Held-to-maturity, Estimated fair value 248 261
Other debt securities    
Amortized cost    
Available-for-sale 25 25
Gross unrealized gains    
Available-for-sale 0 0
Gross unrealized losses    
Available-for-sale 1 0
Estimated fair value    
Available-for-sale 24 25
Available-for-sale, Unrealized Gains, Other | Maximum    
Gross unrealized gains    
Available-for-sale $ 1 $ 1