Fair Value (Fair Value Measurements- Recurring Quantitative Information) (Details) (Fair Value, Measurements, Recurring [Member], Level 3 [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	10,257	10,650
Recurring Liabilities - Fair Value	716	638
Total Recurring Assets Net of Recurring Liabilities - Fair Value	9,541	10,012
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	4,798	5,358
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	6.10%	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)	28.90%	32.10%
Constant default rate (CDR)	16.70%	21.90%
Loss Severity	100.00%	92.90%
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)	6.80%	6.00%
Constant default rate (CDR)	5.60%	6.60%
Loss Severity	53.10%	52.30%
Spread over the benchmark curve	2.49%	2.37%
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	4,081	4,672
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	717	686
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	563	641
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%	1.00%
Loss Severity	14.60%	10.00%
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%	11.10%
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)	5.90%	5.00%
Constant default rate (CDR)	7.60%	8.70%
Loss Severity	73.50%	70.10%
Spread over the benchmark curve	3.52%	3.26%
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	532	610
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	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%	0.80%
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%	2.40%
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%	0.97%
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	201
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%	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%	25.00%
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%	8.30%
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	30	38
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	95.00%	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	88.60%	88.40%
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	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%	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%	20.00%
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%	8.30%
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	845	1,087
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)	3.80%	2.20%
Spread over the benchmark curve	8.89%	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)	32.70%	32.90%
Spread over the benchmark curve	18.88%	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)	11.20%	7.60%
Spread over the benchmark curve	10.36%	10.24%
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	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)	7.00%
Discount rate	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)	16.80%
Discount rate	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)	8.00%
Discount rate	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	893	586
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	0.37%	4.60%
Estimated servicing cash flows	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	40.25%	66.55%
Estimated servicing cash flows	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	5.49%	9.72%
Estimated servicing cash flows	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	1,152	1,069
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	3.2	4.5
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	13.9	10.8
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	7.2
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	469	595
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	154	179
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	3.40%	10.00%
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	114	225
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	5.40%	12.00%
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%	13.00%
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	35.60%	48.40%
Cumulative default rate	90.50%	80.00%
Discount rate	6.40%	12.20%
Loans - Home equity [Member] | Consensus Pricing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Assets - Fair Value	129	123
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%	36.00%
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	51.00%	55.00%
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	375	332
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	375	332
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]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring Liabilities - Fair Value	135	90
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	135	90
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	41.10%	41.70%
Estimated growth rate of Visa Class A share price	14.80%	8.60%
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	41.10%	41.70%
Estimated growth rate of Visa Class A share price	14.80%	8.60%
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	41.10%	41.70%
Estimated growth rate of Visa Class A share price	14.80%	8.60%
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	166	184
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	1.13%	0.13%
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	1.13%	0.13%
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	1.13%	0.13%
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	23	20