Fair Value (Fair Value Measurements - Recurring Quantitative Information) (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 41,785	$ 44,159
Fair Value	3,686	3,423
Derivative Liability	(3,538)	(4,524)
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	41,785	44,159
Loans, fair value	1,238	1,310
Equity investments	2,717	3,147
Derivative Liability	(5,899)	(7,618)
fair value assets	56,862	59,135
Fair value liabilities	6,953	9,378
Residential mortgage-backed non-agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	696	819
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total recurring assets net of recurring liabilities - fair value	7,050	6,831
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	956	1,001
Loans, fair value	726	769
Equity investments	1,952	1,778
Derivative Liability	(152)	(123)
fair value assets	7,448	7,252
Fair value liabilities	398	421
Level 3 | Commercial mortgage loans held for sale | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, fair value	11	33
Level 3 | Residential mortgage-backed non-agency securities | 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]
Securities available for sale	696	819
Level 3 | 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]
Securities available for sale	102	124
Level 3 | Loans - Residential real estate - Uninsured | Consensus pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	546	570
Level 3 | Loans - Residential real estate | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	75	76
Level 3 | Loans - Home equity - First-lien | Consensus pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	18	25
Level 3 | Loans - Home equity | Consensus pricing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	87	98
Level 3 | Equity investments | Multiple of Adjusted Earnings
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	1,952	1,778
Level 3 | Residential mortgage servicing rights | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,654	2,310
Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,032	1,113
Level 3 | Financial derivatives | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(145)	(107)
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	$ 22	$ 8
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.0575	0.0585
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.3610	0.2465
Spread over the benchmark curve | Level 3 | Commercial mortgage loans held for sale | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.1647	0.0959
Spread over the benchmark curve | Level 3 | Residential mortgage-backed non-agency securities | 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	0.0285	0.0289
Spread over the benchmark curve | Level 3 | 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	0.0248	0.0296
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.0337	0.0254
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.1668	0.1653
Spread over the benchmark curve | Level 3 | Residential mortgage servicing rights | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.0765	0.0766
Measurement Input, Constant Prepayment Rate | Level 3 | Residential mortgage-backed non-agency securities | 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 | Residential mortgage-backed non-agency securities | 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 | Residential mortgage-backed non-agency securities | 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	0.037	0.099
Measurement Input, Constant Prepayment Rate | Level 3 | 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 | 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	0.280	0.400
Measurement Input, Constant Prepayment Rate | Level 3 | 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	0.051	0.075
Measurement Input, Constant Prepayment Rate | Level 3 | Residential mortgage servicing rights | 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 | Residential mortgage servicing rights | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.336	0.345
Measurement Input, Constant Prepayment Rate | Level 3 | Residential mortgage servicing rights | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.064	0.067
Measurement Input, Constant Prepayment Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.053	0.039
Measurement Input, Constant Prepayment Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.097	0.098
Measurement Input, Constant Prepayment Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.055	0.043
Measurement Input, Constant Default Rate | Level 3 | Residential mortgage-backed non-agency securities | 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 | Residential mortgage-backed non-agency securities | 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 | Residential mortgage-backed non-agency securities | 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	0.027	0.040
Measurement Input, Constant Default Rate | Level 3 | 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 | 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	0.043	0.073
Measurement Input, Constant Default Rate | Level 3 | 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	0.017	0.021
Cumulative default rate | Level 3 | Loans - Residential real estate - Uninsured | Consensus pricing | Minimum
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 | Loans - Residential real estate - Uninsured | Consensus pricing | Maximum
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 | Loans - Residential real estate - Uninsured | Consensus pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.591	0.662
Cumulative default rate | Level 3 | Loans - Home equity - First-lien | Consensus pricing | Minimum
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 | Loans - Home equity - First-lien | Consensus pricing | Maximum
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 | Loans - Home equity - First-lien | Consensus pricing | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing receivable, measurement input	0.609	0.725
Measurement Input, Loss Severity | Level 3 | Residential mortgage-backed non-agency securities | 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	0.100	0.150
Measurement Input, Loss Severity | Level 3 | Residential mortgage-backed non-agency securities | 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	0.690	0.800
Measurement Input, Loss Severity | Level 3 | Residential mortgage-backed non-agency securities | 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	0.412	0.461
Measurement Input, Loss Severity | Level 3 | 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	0.200	0.200
Measurement Input, Loss Severity | Level 3 | 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 | 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	0.495	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]
Financing receivable, 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]
Financing receivable, 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]
Financing receivable, measurement input	0.054	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]
Financing receivable, 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]
Financing receivable, measurement input	0.000	0.0
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]
Financing receivable, 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]
Financing receivable, measurement input	0.144	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]
Financing receivable, 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]
Financing receivable, 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]
Financing receivable, 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]
Financing receivable, measurement input	0.078	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]
Financing receivable, 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]
Financing receivable, 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]
Financing receivable, measurement input	0.062	0.065
Measurement Input, Discount Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.076	0.078
Measurement Input, Discount Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.100	0.101
Measurement Input, Discount Rate | Level 3 | Commercial Mortgage-Backed Securities | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input	0.096	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]
Financing receivable, measurement input	0.003	0.004
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]
Financing receivable, measurement input	1.000	1.000
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]
Financing receivable, measurement input	0.438	0.462
Multiple of earnings | Level 3 | Equity investments | Multiple of Adjusted Earnings | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	0.045	0.045
Multiple of earnings | Level 3 | Equity investments | Multiple of Adjusted Earnings | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	0.267	0.250
Multiple of earnings | Level 3 | Equity investments | Multiple of Adjusted Earnings | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, measurement input	10.1	0.091
Estimated Conversion Factor | Level 3 | Financial derivatives | Discounted cash flow | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	1.59	1.61
Estimated Annual Growth Rate | Level 3 | Financial derivatives | Discounted cash flow
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, measurement input	0.160	0.160