v3.20.4
Stockholders' Equity and Accumulated Other Comprehensive Income (Loss)(Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Pre-tax AOCI activity, Period Start $ (120) $ (1,289) $ (1,002)
Other Comprehensive Income (Loss), before Tax 1,879 1,169 (287)
Pre-tax AOCI activity, Period End 1,759 (120) (1,289)
Tax Effect, period start [1] 30 325 253
Unrealized holding gains (losses) arising during the period on securities available for sale, Tax (200) (196) 83
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax (1) 7 0
Net actuarial gains and losses arising during the period, tax (36) (50) 4
Other Comprehensive Income (Loss), Tax [1] (474) (295) 72
Tax Effect, period end (444) 30 [1] 325 [1]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start (90) (964) (749)
Reclassification adjustments for securities gains (losses) realized in net income (net of tax) 3 (21) 0
Other comprehensive income (loss), net of tax 1,405 874 (215)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End 1,315 (90) (964)
Accumulated Net Unrealized Loss on Held To Maturity Securities [Member]      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Pre-tax AOCI activity, Period Start (29) (36) (45)
Other Comprehensive Loss, Held-to-maturity Security, Reclassification Adjustment from AOCI for Noncredit Portion of OTTI, before Tax [2] 8 7 9
Pre-tax AOCI activity, Period End (21) (29) (36)
Tax Effect, period start [1] 7 9 12
Reclassification adjustments for Amortization of Unrealized Losses on Securities Transferred to Held to Maturity, Tax [1],[2] (2) (2) (3)
Tax Effect, period end [1] 5 7 9
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start (22) (27) (33)
Reclassification adjustments for Amortization of Unrealized Losses on Securities Transferred to Held to Maturity (net of tax) [2] 6 5 6
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End (16) (22) (27)
Accumulated Net Unrealized Securities Available For Sale Gain (Loss) [Member]      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Pre-tax AOCI activity, Period Start 274 (531) (204)
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax 792 777 (327)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax [3] (4) 28  
Other Comprehensive Income (Loss), before Tax 788 805  
Pre-tax AOCI activity, Period End 1,062 274 (531)
Tax Effect, period start [1] (69) 134 51
Unrealized holding gains (losses) arising during the period on securities available for sale, Tax [1] 200 196 (83)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax [1],[3] 1 (7)  
Other Comprehensive Income (Loss), Tax [1] (199) (203)  
Tax Effect, period end [1] (268) (69) 134
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start 205 (397) (153)
Unrealized holding gains (losses) arising during the period on securities available for sale, net of tax 592 581 (244)
Reclassification adjustments for securities gains (losses) realized in net income (net of tax) [3] (3) 21  
Other comprehensive income (loss), net of tax 589 602  
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End 794 205 (397)
Accumulated Net Gain (Loss) from Derivative Instruments Designated as Cash Flow Hedges [Member]      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Pre-tax AOCI activity, Period Start 430 (84) (68)
Other Comprehensive Income (Loss), before Tax 1,180 514 (16)
Unrealized holding gains (losses) on derivatives arising during the period, before Tax 1,440 490 (4)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax [2] (260) 24 (12)
Pre-tax AOCI activity, Period End 1,610 430 (84)
Tax Effect, period start [1] (108) 21 17
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax [1] (363) (123) 1
Reclassification adjustments for derivatives gains (losses) realized in net income, Tax [1],[2] 65 (6) 3
Other Comprehensive Income (Loss), Tax [1] (298) (129) 4
Tax Effect, period end [1] (406) (108) 21
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start 322 (63) (51)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax 1,077 367 (3)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax [2] (195) 18 (9)
Other comprehensive income (loss), net of tax   385 (12)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End 1,204 322 (63)
Accumulated Defined Benefit Pension Plans Adjustment [Member]      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Pre-tax AOCI activity, Period Start (795) (638) (685)
Other Comprehensive Income (Loss), before Tax (97) (157) 47
Net actuarial gains (losses) arising during the period, before tax (144) (200) 11
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, before Tax [4] 47 43 36
Pre-tax AOCI activity, Period End (892) (795) (638)
Tax Effect, period start [1] 200 161 173
Net actuarial gains and losses arising during the period, tax [1] 36 50 (4)
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income, Tax [1],[4] (11) (11) (8)
Other Comprehensive Income (Loss), Tax [1] 25 39 (12)
Tax Effect, period end [1] 225 200 161
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start (595) (477) (512)
Net actuarial gains (losses) arising during the period (net of tax) (108) (150) 7
Reclassification adjustments for amortization of actuarial (gains) losses and settlements realized in net income (net of tax) [4] 36 32 28
Other comprehensive income (loss), net of tax (72) (118) 35
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End $ (667) $ (595) $ (477)
[1] The tax impact of each component of AOCI is calculated using an effective tax rate of approximately 25%.
[2] Reclassification amount is recognized in net interest income in the consolidated statements of income.
[3] Reclassification amount is recognized in securities gains (losses), net in the consolidated statements of income.
[4] Reclassification amount is recognized in other non-interest expense in the consolidated statements of income. Additionally, these accumulated other comprehensive income (loss) components are included in the computation of net periodic pension cost (see Note 18 for additional details).