v3.26.1
Derivative Financial Instruments - Impact on Derivatives and Hedged Items on Consolidated Statement of Income (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]        
Amount of Gain
(Loss) on Derivative
Recognized in
Consolidated
Statement of Income $ 46 $ (63) $ 86 $ (144)
Amount of Gain
(Loss) on Hedged
Item Recognized in
Consolidated
Statement of Income (46) 63 (86) 144
Net unrealized losses on AFS investment securities designated in fair value hedges 114 110 219 320
Income Statement Location [Axis]: us-gaap:InterestIncomeExpenseNet | Interest rate contracts | Long-term debt        
Derivative Instruments and Hedging Activities Disclosures [Line Items]        
Amount of Gain
(Loss) on Derivative
Recognized in
Consolidated
Statement of Income (105) 95 (168) 245
Amount of Gain
(Loss) on Hedged
Item Recognized in
Consolidated
Statement of Income 105 (95) 168 (245)
Income Statement Location [Axis]: us-gaap:InterestIncomeExpenseNet | Interest rate contracts | Available-for-sale securities        
Derivative Instruments and Hedging Activities Disclosures [Line Items]        
Amount of Gain
(Loss) on Derivative
Recognized in
Consolidated
Statement of Income 153 (154) 279 (388)
Amount of Gain
(Loss) on Hedged
Item Recognized in
Consolidated
Statement of Income (153) 154 (279) 388
Income Statement Location [Axis]: us-gaap:NoninterestIncomeOther | Foreign exchange contracts | Available-for-sale securities        
Derivative Instruments and Hedging Activities Disclosures [Line Items]        
Amount of Gain
(Loss) on Derivative
Recognized in
Consolidated
Statement of Income (2) (4) (25) (1)
Amount of Gain
(Loss) on Hedged
Item Recognized in
Consolidated
Statement of Income $ 2 $ 4 $ 25 $ 1