v3.26.1
Shareholders' Equity and Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]                
Pre-tax AOCI activity, Period Start $ (2,302) $ (2,057) $ (3,053) $ (3,912) $ (2,057) $ (3,912)    
Tax Effect, period start 584 522 770 984 522 984    
Unrealized losses on securities transferred to held to maturity during the period, tax 0   (19)   0 (57)    
Unrealized losses on securities transferred from available for sale during the period 0   (55)   0 (170)    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, tax 7   11   13 18    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, after Tax (19)   (32)   (37) (47)    
Other Comprehensive Income (Loss), before Tax (272)   422   (517) 1,272    
Other Comprehensive Income (Loss), Tax 68   (106)   130 (320)    
Other comprehensive income (loss), net of tax (204) (183) 316 636 (387) 952    
Stockholders Equity Other Tax           0    
Stockholders Equity Other After Tax           9    
Stockholders Equity Other Before Tax           9    
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityBeforeAdjustmentTax 0   (19)   0 (57)    
Unrealized losses on securities transferred to held to maturity during the period 0   55   0 170    
Unrealized holding gains (losses) on available for sale securities, tax 24   (43)   63 (156)    
Unrealized holding gains (losses) arising during the period on securities available for sale, net of tax (70)   127   (186) 472    
Reclassification adjustments for securities gains (losses) realized in net income, tax 10   0   11 6    
Reclassification adjustments for securities gains (losses) realized in net income (net of tax) (31)   (1)   (33) (20)    
Unrealized holding gains (losses) on derivatives arising during the period (212)   106   (330) 309    
Net change in unrealized gains (losses) on derivative instruments, net of tax (187)   151   (278) 404    
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income (net of tax) 3   5   7 9    
Pre-tax AOCI activity, Period End (2,574) (2,302) (2,631) (3,053) (2,574) (2,631)    
Tax Effect, period end 652 584 664 770 652 664    
Net actuarial gains (losses) arising during the period (net of tax) 0   0   0 0    
Net actuarial gains and losses arising during the period, tax 0   0   0 0    
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start (1,718) (1,535) (2,283) (2,928) (1,535) (2,928)    
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End (1,922) (1,718) (1,967) (2,283) (1,922) (1,967)    
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 (843) (867) (875) (744) (867) (744)    
Tax Effect, period start 213 219 219 188 219 188    
OCIDebtSecuritiesAvailableForSaleTransferToHeldToMaturityUnrealizedGainLossBeforeAdjustmentBeforeTax     (74)     (227)    
Unrealized losses on securities transferred to held to maturity during the period, tax     19     57    
Unrealized losses on securities transferred from available for sale during the period     (55)     (170)    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, before Tax 26   43   50 65    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, tax (7)   (11)   (13) (18)    
Reclassification adjustments for amortization on unrealized losses on securities transferred to held for maturity, after Tax 19   32   37 47    
Other Comprehensive Income (Loss), before Tax     (31)     (162)    
Other Comprehensive Income (Loss), Tax     8     39    
Other comprehensive income (loss), net of tax     (23)     (123)    
AOCI component, net of tax (611) (630) (679) (656) (611) (679) $ (648) $ (556)
Pre-tax AOCI activity, Period End (817) (843) (906) (875) (817) (906)    
Tax Effect, period end 206 213 227 219 206 227    
Unrealized gains (losses) on securities available for sale:                
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]                
Pre-tax AOCI activity, Period Start (726) (574) (1,322) (1,958) (574) (1,958)    
Tax Effect, period start 184 146 333 490 146 490    
Other Comprehensive Income (Loss), before Tax (53)   245   (205) 881    
Other Comprehensive Income (Loss), Tax 14   (62)   52 (219)    
Other comprehensive income (loss), net of tax (39)   183   (153) 662    
AOCI component, net of tax (581) (542) (806) (989) (581) (806) (428) (1,468)
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityArisingDuringBeforeTax     74     227    
OCIDebtSecuritiesAvailableForSaleUnrealizedGainLossTransferredToHeldToMaturityBeforeAdjustmentTax     19     57    
Unrealized losses on securities transferred to held to maturity during the period     55     170    
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax (94)   170   (249) 628    
Unrealized holding gains (losses) on available for sale securities, tax 24   (43)   63 (156)    
Unrealized holding gains (losses) arising during the period on securities available for sale, net of tax (70)   127   (186) 472    
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax 41   1   44 26    
Reclassification adjustments for securities gains (losses) realized in net income, tax (10)   0   (11) (6)    
Reclassification adjustments for securities gains (losses) realized in net income (net of tax) 31   1   33 20    
Pre-tax AOCI activity, Period End (779) (726) (1,077) (1,322) (779) (1,077)    
Tax Effect, period end 198 184 271 333 198 271    
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 (213) (91) (323) (662) (91) (662)    
Tax Effect, period start 54 23 82 168 23 168    
Other Comprehensive Income (Loss), before Tax (250)   202   (372) 541    
Other Comprehensive Income (Loss), Tax 63   (51)   94 (137)    
Other comprehensive income (loss), net of tax (187)   151     404    
AOCI component, net of tax (346) (159) (90) (241) (346) (90) (68) (494)
OCI, before Reclassifications, before Tax, Attributable to Parent (284)   142   (442) 414    
OCI, before reclassifications, tax, attributable to parent 72   (36)   112 (105)    
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent (34)   (60)   (70) (127)    
Reclassification from AOCI, Current Period, Tax 9   (15)   (18) (32)    
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent 25   45   52 (95)    
Pre-tax AOCI activity, Period End (463) (213) (121) (323) (463) (121)    
Tax Effect, period end 117 54 31 82 117 31    
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 (520) (525) (542) (548) (525) (548)    
Tax Effect, period start 133 134 136 138 134 138    
AOCI component, net of tax (384) (387) (401) (406) (384) (401) $ (391) $ (410)
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, before Tax (5)   6   10 12    
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, Tax 2   1   3 3    
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income (net of tax) (3)   5   7 9    
Pre-tax AOCI activity, Period End (515) (520) (536) (542) (515) (536)    
Tax Effect, period end $ 131 $ 133 $ 135 $ 136 $ 131 $ 135