Fair Value (Fair Value Measurements - Recurring Quantitative Information) (Details) $ in Millions	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	$ 63,318	$ 62,039
Mortgage servicing rights	3,564	3,711
Financial derivatives - Swaps related to sales of certain Visa Class B common shares	(2,375)	(3,168)
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	63,318	62,039
Loans, fair value	1,149	1,156
Equity investments	2,995	3,132
Financial derivatives - Swaps related to sales of certain Visa Class B common shares	(4,730)	(5,495)
Recurring assets - fair value	79,965	77,246
Recurring liabilities - fair value	7,826	6,999
Residential mortgage-backed non-agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	596	603
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	2,223	2,111
Financial derivatives - Swaps related to sales of certain Visa Class B common shares	(157)	(143)
Insignificant assets, net of liabilities fair value disclosure	29	45
Total recurring assets net of recurring liabilities - fair value	7,118	7,094
Level 3 | Consumer Portfolio Segment | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	75	73
Level 3 | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	497	504
Level 3 | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	13	14
Level 3 | Consumer Portfolio Segment | Loans - Home equity - Second-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	78	79
Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	841	853
Loans, fair value	663	670
Equity investments	2,223	2,111
Financial derivatives - Swaps related to sales of certain Visa Class B common shares	(161)	(150)
Recurring assets - fair value	7,421	7,431
Recurring liabilities - fair value	303	337
Level 3 | Commercial mortgage loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, fair value	4	4
Level 3 | Residential mortgage-backed non-agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	596	603
Level 3 | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities – available-for-sale	92	93
Level 3 | Residential mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, fair value	104
Mortgage servicing rights	2,523	2,626
Level 3 | Commercial mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	$ 1,041	$ 1,085
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.0560	0.0560
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.1085	0.1075
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.0978	0.0970
Spread over the benchmark curve | Level 3 | Residential mortgage-backed non-agency securities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.0193	0.0216
Spread over the benchmark curve | Level 3 | Asset-backed | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.0163	0.0170
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.0455	0.0381
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.2201	0.2202
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.0755	0.0755
Constant prepayment rate | Level 3 | Residential mortgage-backed non-agency securities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.010	0.010
Constant prepayment rate | Level 3 | Residential mortgage-backed non-agency securities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.279	0.279
Constant prepayment rate | Level 3 | Residential mortgage-backed non-agency securities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.036	0.042
Constant prepayment rate | Level 3 | Asset-backed | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.010	0.010
Constant prepayment rate | Level 3 | Asset-backed | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.080	0.080
Constant prepayment rate | Level 3 | Asset-backed | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.042	0.038
Constant prepayment rate | Level 3 | Residential mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.000	0.000
Constant prepayment rate | Level 3 | Residential mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.496	0.403
Constant prepayment rate | Level 3 | Residential mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.067	0.064
Constant prepayment rate | Level 3 | Commercial mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.044	0.043
Constant prepayment rate | Level 3 | Commercial mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.076	0.074
Constant prepayment rate | Level 3 | Commercial mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.046	0.044
Constant default rate | Level 3 | Residential mortgage-backed non-agency securities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.000	0.000
Constant default rate | Level 3 | Residential mortgage-backed non-agency securities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.120	0.120
Constant default rate | Level 3 | Residential mortgage-backed non-agency securities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.017	0.019
Constant default rate | Level 3 | Asset-backed | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.000	0.000
Constant default rate | Level 3 | Asset-backed | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.074	0.071
Constant default rate | Level 3 | Asset-backed | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.016	0.015
Loss severity | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.000	0.000
Loss severity | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.000	0.000
Loss severity | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1.000	1.000
Loss severity | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1.000	1.000
Loss severity | Level 3 | Weighted Average | Consumer Portfolio Segment | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.060	0.060
Loss severity | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.048	0.050
Loss severity | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.121	0.123
Loss severity | Level 3 | Residential mortgage-backed non-agency securities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.150	0.150
Loss severity | Level 3 | Residential mortgage-backed non-agency securities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	1.000	0.690
Loss severity | Level 3 | Residential mortgage-backed non-agency securities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.422	0.424
Loss severity | Level 3 | Asset-backed | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.350	0.350
Loss severity | Level 3 | Asset-backed | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	1.000	1.000
Loss severity | Level 3 | Asset-backed | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.436	0.453
Loss severity | Level 3 | Residential mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.000
Loss severity | Level 3 | Residential mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1
Loss severity | Level 3 | Residential mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.059
Cumulative default rate | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.036	0.036
Cumulative default rate | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.036	0.036
Cumulative default rate | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1.000	1.000
Cumulative default rate | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1.000	1.000
Cumulative default rate | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.516	0.525
Cumulative default rate | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.504	0.516
Cumulative default rate | Level 3 | Residential mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.036
Cumulative default rate | Level 3 | Residential mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1
Cumulative default rate | Level 3 | Residential mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.399
Discount rate | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.055	0.055
Discount rate | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.055	0.055
Discount rate | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.075	0.075
Discount rate | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.075	0.075
Discount rate | Level 3 | Weighted Average | Consumer Portfolio Segment | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.070	0.072
Discount rate | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Residential real estate - Uninsured
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.057	0.057
Discount rate | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Home equity - First-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.061	0.061
Discount rate | Level 3 | Residential mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.055
Discount rate | Level 3 | Residential mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.090
Discount rate | Level 3 | Residential mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.060
Discount rate | Level 3 | Commercial mortgage servicing rights | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.093	0.096
Discount rate | Level 3 | Commercial mortgage servicing rights | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.112	0.115
Discount rate | Level 3 | Commercial mortgage servicing rights | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.109	0.112
Credit and liquidity discount | Level 3 | Minimum | Consumer Portfolio Segment | Loans - Home equity - Second-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.003	0.003
Credit and liquidity discount | Level 3 | Maximum | Consumer Portfolio Segment | Loans - Home equity - Second-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	1.000	1.000
Credit and liquidity discount | Level 3 | Weighted Average | Consumer Portfolio Segment | Loans - Home equity - Second-lien
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.401	0.412
Multiple of earnings | Level 3 | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	0.055	0.055
Multiple of earnings | Level 3 | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	0.267	0.267
Multiple of earnings | Level 3 | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	0.104	0.105
Estimated Conversion Factor | Level 3 | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	1.53	1.54
Estimated Annual Growth Rate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.160	0.160