v3.25.4
Shareholders' Equity and Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2025
Jun. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]            
Pre-tax AOCI activity, Period Start     $ (3,912) $ (3,773) $ (4,481)  
Tax Effect, period start     984 961 1,138  
Unrealized losses on securities transferred to held to maturity during the period, tax     (57) (192) 0  
Unrealized losses on securities transferred from available for sale during the period     (170) (562) 0  
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, tax     26 5 1  
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, after Tax     (78) (14) (1)  
Other Comprehensive Income (Loss), before Tax     1,855 (139) 708  
Other Comprehensive Income (Loss), Tax     (462) 23 (177)  
Other comprehensive income (loss), net of tax     1,393 (116) 531  
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityBeforeAdjustmentTax     (57) (192) 0  
Unrealized losses on securities transferred to held to maturity during the period     170 562 0  
Unrealized holding gains (losses) on available for sale securities, tax     (274) 31 (168)  
Unrealized holding gains (losses) arising during the period on securities available for sale, net of tax     830 (130) 501  
Reclassification adjustments for securities gains (losses) realized in net income, tax     13 52 1  
Reclassification adjustments for securities gains (losses) realized in net income (net of tax)     (40) (156) (4)  
Unrealized holding gains (losses) on derivatives arising during the period     245 (511) (124)  
Net change in unrealized gains (losses) on derivative instruments, net of tax     426 (197) 52  
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income (net of tax)     20 23 34  
Pre-tax AOCI activity, Period End     (2,057) (3,912) (3,773)  
Tax Effect, period end     522 984 961  
Net actuarial gains and losses arising during the period, tax     (3) 9 (21)  
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start     (2,928) (2,812) (3,343)  
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End     (1,535) (2,928) (2,812)  
Unrealized losses on securities transferred to held to maturity:            
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]            
Pre-tax AOCI activity, Period Start     (744) (9) (11)  
Tax Effect, period start     188 1 2  
OCIDebtSecuritiesAvailableForSaleTransferToHeldToMaturityUnrealizedGainLossBeforeAdjustmentBeforeTax     (227) (754)    
Unrealized losses on securities transferred to held to maturity during the period, tax     57 192    
Unrealized losses on securities transferred from available for sale during the period     (170) (562)    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, before Tax     104 19 2  
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, tax     (26) (5) (1)  
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, after Tax     78 14 1  
Other Comprehensive Income (Loss), before Tax     (123) (735)    
Other Comprehensive Income (Loss), Tax     31 187    
Other comprehensive income (loss), net of tax     (92) (548)    
AOCI component, net of tax     (648) (556) (8) $ (9)
Pre-tax AOCI activity, Period End     (867) (744) (9)  
Tax Effect, period end     219 188 1  
Unrealized gains (losses) on securities available for sale:            
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]            
Pre-tax AOCI activity, Period Start     (1,958) (2,759) (3,433)  
Tax Effect, period start     490 703 872  
Other Comprehensive Income (Loss), before Tax     1,384 801 674  
Other Comprehensive Income (Loss), Tax     (344) (213) (169)  
Other comprehensive income (loss), net of tax     1,040 588 505  
AOCI component, net of tax     (428) (1,468) (2,056) (2,561)
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityArisingDuringBeforeTax $ 74 $ 153 227 754    
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityBeforeAdjustmentTax     57 192    
Unrealized losses on securities transferred to held to maturity during the period     170 562    
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax     1,104 (161) 669  
Unrealized holding gains (losses) on available for sale securities, tax     (274) 31 (168)  
Unrealized holding gains (losses) arising during the period on securities available for sale, net of tax     830 (130) 501  
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax     53 208 5  
Reclassification adjustments for securities gains (losses) realized in net income, tax     (13) (52) (1)  
Reclassification adjustments for securities gains (losses) realized in net income (net of tax)     40 156 4  
Pre-tax AOCI activity, Period End     (574) (1,958) (2,759)  
Tax Effect, period end     146 490 703  
Unrealized gains (losses) on derivative instruments designated as cash flow hedges:            
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]            
Pre-tax AOCI activity, Period Start     (662) (399) (468)  
Tax Effect, period start     168 102 119  
Other Comprehensive Income (Loss), before Tax     571 (263) 69  
Other Comprehensive Income (Loss), Tax     (145) 66 (17)  
Other comprehensive income (loss), net of tax       (197) 52  
AOCI component, net of tax     (68) (494) (297) (349)
OCI, before Reclassifications, before Tax, Attributable to Parent     329 (683) (167)  
OCI, before reclassifications, tax, attributable to parent     (84) 172 43  
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent     (242) (420) (236)  
Reclassification from AOCI, Current Period, Tax     (61) (106) (60)  
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent     181 (314) (176)  
Pre-tax AOCI activity, Period End     (91) (662) (399)  
Tax Effect, period end     23 168 102  
Defined benefit pension plans and other post employment benefit plans:            
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]            
Pre-tax AOCI activity, Period Start     (548) (606) (569)  
Tax Effect, period start     138 155 145  
Other Comprehensive Income (Loss), before Tax     23 58 (37)  
Other Comprehensive Income (Loss), Tax     (4) (17) 10  
Other comprehensive income (loss), net of tax     19 41 (27)  
AOCI component, net of tax     (391) (410) (451) $ (424)
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, before Tax     27 31 45  
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, Tax     7 8 11  
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income (net of tax)     20 23 34  
Pre-tax AOCI activity, Period End     (525) (548) (606)  
Tax Effect, period end     134 138 155  
Net actuarial gains and losses arising during the period, tax     3 (9) 21  
Net actuarial gains (losses) arising during the period, before tax     $ (4) $ 27 $ (82)