Fair Value (Fair Value Measurements- Recurring Quantitative Information) (Details) - Fair Value, Measurements, Recurring [Member] - Level 3 [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 9,719	$ 10,257
Recurring Liabilities - Fair Value	673	716
Total Recurring Assets Net of Recurring Liabilities - Fair Value	9,046	9,541
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 4,424	$ 4,798
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	1.00%	1.00%
Constant default rate (CDR)	0.00%	0.00%
Loss Severity	10.00%	6.10%
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	24.20%	28.90%
Constant default rate (CDR)	16.70%	16.70%
Loss Severity	98.50%	100.00%
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	6.90%	6.80%
Constant default rate (CDR)	5.40%	5.60%
Loss Severity	53.10%	53.10%
Spread over the benchmark curve	2.42%	2.49%
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Third Party Pricing Services Available [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 3,749	$ 4,081
Available-for-sale Securities [Member] | Residential Mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Third Party Pricing Services Unavailable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	675	717
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 531	$ 563
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	1.00%	1.00%
Constant default rate (CDR)	1.70%	1.70%
Loss Severity	15.00%	14.60%
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	15.70%	15.70%
Constant default rate (CDR)	13.90%	13.90%
Loss Severity	100.00%	100.00%
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	6.40%	5.90%
Constant default rate (CDR)	6.90%	7.60%
Loss Severity	76.40%	73.50%
Spread over the benchmark curve	3.08%	3.52%
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Third Party Pricing Services Available [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 500	$ 532
Available-for-sale Securities [Member] | Asset backed [Member] | Priced By A Third Party Vendor Using Discounted Cash Flow Pricing Model [Member] | Third Party Pricing Services Unavailable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	31	31
Available-for-sale Securities [Member] | State and Municipal [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value		$ 132
Available-for-sale Securities [Member] | State and Municipal [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve		0.55%
Available-for-sale Securities [Member] | State and Municipal [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve		1.65%
Available-for-sale Securities [Member] | State and Municipal [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve		0.67%
Available-for-sale Securities [Member] | State and Municipal [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value		$ 2
Available-for-sale Securities [Member] | State and Municipal [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		0.00%
Available-for-sale Securities [Member] | State and Municipal [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		20.00%
Available-for-sale Securities [Member] | State and Municipal [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		14.90%
Available-for-sale Securities [Member] | Other Debt Securities [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 33	$ 30
Available-for-sale Securities [Member] | Other Debt Securities [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	7.00%	7.00%
Available-for-sale Securities [Member] | Other Debt Securities [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	100.00%	95.00%
Available-for-sale Securities [Member] | Other Debt Securities [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	88.40%	88.60%
Trading Securities - Debt [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value		$ 32
Trading Securities - Debt [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		0.00%
Trading Securities - Debt [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		15.00%
Trading Securities - Debt [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount		8.00%
Mortgage Servicing Rights [Member] | Residential Mortgage [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 1,015	$ 845
Mortgage Servicing Rights [Member] | Residential Mortgage [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	0.30%	3.80%
Spread over the benchmark curve	5.58%	8.89%
Mortgage Servicing Rights [Member] | Residential Mortgage [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	38.40%	32.70%
Spread over the benchmark curve	18.61%	18.88%
Mortgage Servicing Rights [Member] | Residential Mortgage [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	9.70%	11.20%
Spread over the benchmark curve	9.66%	10.36%
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 543	$ 506
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	4.80%	7.00%
Discount rate	3.50%	2.50%
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	13.80%	16.80%
Discount rate	9.10%	8.60%
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)	5.90%	8.00%
Discount rate	7.60%	6.60%
Loans Held For Sale [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 757	$ 893
Loans Held For Sale [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	0.32%	0.37%
Estimated servicing cash flows	0.00%	0.00%
Loans Held For Sale [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	31.15%	40.25%
Estimated servicing cash flows	5.20%	2.00%
Loans Held For Sale [Member] | Commercial Mortgage [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	4.55%	5.49%
Estimated servicing cash flows	2.50%	1.20%
Equity Investments [Member] | Direct equity investments [Member] | Multiple Of Adjusted Earnings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 1,191	$ 1,152
Equity Investments [Member] | Direct equity investments [Member] | Multiple Of Adjusted Earnings [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	4.2	3.2
Equity Investments [Member] | Direct equity investments [Member] | Multiple Of Adjusted Earnings [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	14	13.9
Equity Investments [Member] | Direct equity investments [Member] | Multiple Of Adjusted Earnings [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Multiple of earnings	7.7	7.7
Equity Investments [Member] | Indirect Equity Investments [Member] | Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 425	$ 469
Loans - Residential real estate [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 123	$ 154
Loans - Residential real estate [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss Severity	8.00%	8.00%
Discount rate	3.50%	3.40%
Loans - Residential real estate [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 123	$ 114
Loans - Residential real estate [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss Severity	0.00%	0.00%
Cumulative default rate	2.00%	2.00%
Discount rate	4.90%	5.40%
Loans - Residential real estate [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss Severity	100.00%	100.00%
Cumulative default rate	100.00%	100.00%
Discount rate	7.00%	7.00%
Loans - Residential real estate [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss Severity	30.20%	35.60%
Cumulative default rate	86.60%	90.50%
Discount rate	5.10%	6.40%
Loans - Home equity [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 119	$ 129
Loans - Home equity [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	26.00%	26.00%
Loans - Home equity [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	99.00%	99.00%
Loans - Home equity [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit and Liquidity discount	52.00%	51.00%
Other Assets [Member] | BlackRock Series C Preferred Stock | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 363	$ 375
Other Assets [Member] | BlackRock Series C Preferred Stock | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Other Assets [Member] | BlackRock Series C Preferred Stock | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Other Assets [Member] | BlackRock Series C Preferred Stock | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Financial Derivatives [Member] | BlackRock LTIP [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Liabilities - Fair Value	$ 363	$ 375
Financial Derivatives [Member] | BlackRock LTIP [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Financial Derivatives [Member] | BlackRock LTIP [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Financial Derivatives [Member] | BlackRock LTIP [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidity Discount	20.00%	20.00%
Financial Derivatives [Member] | Visa Class B Swap [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Liabilities - Fair Value	$ 122	$ 135
Financial Derivatives [Member] | Visa Class B Swap [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated conversion factor of Class B shares into Class A shares	164.30%	41.10%
Estimated growth rate of Visa Class A share price	17.30%	14.80%
Financial Derivatives [Member] | Visa Class B Swap [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated conversion factor of Class B shares into Class A shares	164.30%	41.10%
Estimated growth rate of Visa Class A share price	17.30%	14.80%
Financial Derivatives [Member] | Visa Class B Swap [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated conversion factor of Class B shares into Class A shares	164.30%	41.10%
Estimated growth rate of Visa Class A share price	17.30%	14.80%
Other borrowed funds [Member] | Non-Agency Securitization [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Liabilities - Fair Value	$ 154	$ 166
Other borrowed funds [Member] | Non-Agency Securitization [Member] | Consensus Pricing [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	1.12%	1.13%
Credit and Liquidity discount	0.00%	0.00%
Other borrowed funds [Member] | Non-Agency Securitization [Member] | Consensus Pricing [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	1.12%	1.13%
Credit and Liquidity discount	99.00%	99.00%
Other borrowed funds [Member] | Non-Agency Securitization [Member] | Consensus Pricing [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Spread over the benchmark curve	1.12%	1.13%
Credit and Liquidity discount	18.00%	18.00%
Insignificant Assets, Net of Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	$ 38	$ 23