v3.26.1
OTHER COMPREHENSIVE INCOME - AOCI Roll Forward (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period $ 24,379 $ 19,782
Other comprehensive income (loss) before reclassifications (137) 409
Amounts reclassified from AOCI to earnings (14) 24
Other comprehensive income (loss), net of tax (151) 433
Balance, end of period 32,581 20,486
Reclassification out of Accumulated Other Comprehensive Income    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Debt securities transferred from available-for-sale (42) (49)
AOCI    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period (1,908) (2,866)
Other comprehensive income (loss), net of tax (151) 433
Balance, end of period (2,059) (2,433)
Unrealized gains (losses) on available-for-sale securities, net of hedges    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period (1,738) (2,365)
Other comprehensive income (loss) before reclassifications (57) 253
Amounts reclassified from AOCI to earnings (19) 2
Other comprehensive income (loss), net of tax (76) 255
Balance, end of period (1,814) (2,110)
Net change related to cash flow hedges on loans    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period 27 (267)
Other comprehensive income (loss) before reclassifications (81) 155
Amounts reclassified from AOCI to earnings 5 22
Other comprehensive income (loss), net of tax (76) 177
Balance, end of period (49) (90)
Translation adjustments, net of hedges    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period (4) (12)
Other comprehensive income (loss) before reclassifications 0 1
Amounts reclassified from AOCI to earnings 0 0
Other comprehensive income (loss), net of tax 0 1
Balance, end of period (4) (11)
Unrealized losses for pension and other post-retirement obligations    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, beginning of period (193) (222)
Other comprehensive income (loss) before reclassifications 1 0
Amounts reclassified from AOCI to earnings 0 0
Other comprehensive income (loss), net of tax 1 0
Balance, end of period $ (192) $ (222)