Fair Value (Fair Value Measurements - Recurring Quantitative Information) (Details) - Fair Value, Recurring $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 56,102	$ 59,135
Financial and nonfinancial liabilities, fair value disclosure	(8,486)	(9,378)
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	6,987	7,252
Financial and nonfinancial liabilities, fair value disclosure	(384)	(421)
Total recurring assets net of recurring liabilities - fair value	6,603	6,831
Level 3 | Loans held for sale | Commercial mortgage loans held for sale | Discounted Cash Flow, Spread Over the Benchmark Curve
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 25	$ 33
Level 3 | Loans held for sale | Commercial mortgage loans held for sale | Discounted Cash Flow, Spread Over the Benchmark Curve | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	5.90%	5.85%
Level 3 | Loans held for sale | Commercial mortgage loans held for sale | Discounted Cash Flow, Spread Over the Benchmark Curve | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	24.40%	24.65%
Level 3 | Loans held for sale | Commercial mortgage loans held for sale | Discounted Cash Flow, Spread Over the Benchmark Curve | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	12.75%	9.59%
Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 768	$ 819
Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	2.31%	2.89%
Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 117	$ 124
Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	2.85%	2.96%
Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 556	$ 570
Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	3.60%	3.60%
Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	100.00%	100.00%
Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	61.00%	66.20%
Level 3 | Loans - Residential real estate | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 76	$ 76
Level 3 | Loans - Home equity - First-lien | Consensus Pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 21	$ 25
Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	3.60%	3.60%
Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	100.00%	100.00%
Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default rate	68.20%	72.50%
Level 3 | Loans - Home equity | Consensus Pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 92	$ 98
Level 3 | Equity investments | Multiple of adjusted earnings
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 1,623	$ 1,778
Level 3 | Equity investments | Multiple of adjusted earnings | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	0.045	0.045
Level 3 | Equity investments | Multiple of adjusted earnings | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	0.200	0.250
Level 3 | Equity investments | Multiple of adjusted earnings | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	0.093	0.091
Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 1,106	$ 1,113
Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets - fair value	$ 2,349	$ 2,310
Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	2.54%	2.54%
Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	16.52%	16.53%
Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	7.67%	7.66%
Level 3 | Financial derivatives | Visa Class B Swap | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and nonfinancial liabilities, fair value disclosure	$ (131)	$ (107)
Estimated growth rate of Visa Class A share price	16.00%	16.00%
Level 3 | Financial derivatives | Visa Class B Swap | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated conversion factor of Class B shares into Class A shares	159.00%	160.60%
Level 3 | Insignificant Assets, Net of Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Insignificant assets, fair value disclosure	$ 1	$ (8)
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.010	0.010
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.279	0.279
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.047	0.099
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.010	0.010
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.400	0.400
Measurement Input, Constant Prepayment Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.061	0.075
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.040	0.039
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.111	0.098
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.044	0.043
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.000	0.000
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.419	0.345
Measurement Input, Constant Prepayment Rate | Level 3 | Mortgage Servicing Rights | Residential mortgage loans held for sale | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.069	0.067
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.000	0.000
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.120	0.130
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.030	0.040
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.000	0.000
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.073	0.073
Measurement Input, Constant Default Rate | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.020	0.021
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.150	0.150
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.833	0.800
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Residential mortgage-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.455	0.461
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.300	0.200
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	1.000	1.000
Measurement Input, Loss Severity | Level 3 | Securities available for sale | Asset-backed | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, measurement input	0.506	0.490
Measurement Input, Loss Severity | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.000	0.000
Measurement Input, Loss Severity | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	1.000	1.000
Measurement Input, Loss Severity | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.057	0.062
Measurement Input, Loss Severity | Level 3 | Loans - Residential real estate | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.060	0.060
Measurement Input, Loss Severity | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.000	0.000
Measurement Input, Loss Severity | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	1.000	1.000
Measurement Input, Loss Severity | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.159	0.153
Measurement Input, Discount Rate | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.055	0.055
Measurement Input, Discount Rate | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.075	0.075
Measurement Input, Discount Rate | Level 3 | Loans - Residential real estate - Uninsured | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.058	0.059
Measurement Input, Discount Rate | Level 3 | Loans - Residential real estate | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.084	0.079
Measurement Input, Discount Rate | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.055	0.055
Measurement Input, Discount Rate | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.075	0.075
Measurement Input, Discount Rate | Level 3 | Loans - Home equity - First-lien | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, measurement input	0.063	0.065
Measurement Input, Discount Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.067	0.078
Measurement Input, Discount Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.103	0.101
Measurement Input, Discount Rate | Level 3 | Mortgage Servicing Rights | Commercial mortgage loans held for sale | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.099	0.098
Credit And Liquidity Discount | Level 3 | Loans - Home equity | Consensus Pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and liquidity discount	0.40%	0.40%
Credit And Liquidity Discount | Level 3 | Loans - Home equity | Consensus Pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and liquidity discount	100.00%	100.00%
Credit And Liquidity Discount | Level 3 | Loans - Home equity | Consensus Pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and liquidity discount	45.00%	46.20%