Fair Value (Fair Value Measurements- Nonrecurring Quantitative Information) (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	$ 1,069	[1]
Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	81	[1]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	1,037		1,081	[1]
Level 3 [Member] | Nonaccrual Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	298	[1]	253	[1]
Level 3 [Member] | Nonaccrual Loans [Member] | Fair Value Of Collateral [Member] | Loss Severity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum % or bps amount)	0.40%
Range (Maximum % or bps amount)	95.30%
Weighted Average (% or bps amount)	37.90%
Level 3 [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	49		130	[1]
Level 3 [Member] | Loans Held For Sale [Member] | Discounted Cash Flow [Member] | Spread Over The Benchmark Curve [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum % or bps amount)	0.55%	[2]
Range (Maximum % or bps amount)	0.62%	[2]
Weighted Average (% or bps amount)	0.56%	[2]
Level 3 [Member] | Loans Held For Sale [Member] | Discounted Cash Flow [Member] | Embedded Servicing Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum % or bps amount)	1.30%
Range (Maximum % or bps amount)	2.60%
Weighted Average (% or bps amount)	1.40%
Level 3 [Member] | Equity Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value			1	[1]
Level 3 [Member] | Commercial Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	389	[1]	457	[1]
Level 3 [Member] | Commercial Mortgage Servicing Rights [Member] | Discounted Cash Flow [Member] | Constant Prepayment Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum % or bps amount)	5.00%
Range (Maximum % or bps amount)	21.00%
Weighted Average (% or bps amount)	6.70%
Level 3 [Member] | Commercial Mortgage Servicing Rights [Member] | Discounted Cash Flow [Member] | Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum % or bps amount)	6.00%
Range (Maximum % or bps amount)	8.00%
Weighted Average (% or bps amount)	7.90%
Level 3 [Member] | OREO and foreclosed assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	287	[1]	223	[1]
Level 3 [Member] | OREO and foreclosed assets [Member] | Fair value of property | Appraised Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum $ Amount)	0	[3]
Range (Maximum $ Amount)	12.0	[3]
Weighted Average ($ Amount)	0.5	[3]
Level 3 [Member] | OREO and foreclosed assets [Member] | Fair value of property | Sales Price [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum $ Amount)	0	[3]
Range (Maximum $ Amount)	5.0	[3]
Weighted Average ($ Amount)	0.3	[3]
Level 3 [Member] | Long-lived assets held for sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	14	[1]	17	[1]
Level 3 [Member] | Long-lived assets held for sale [Member] | Fair value of property | Appraised Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum $ Amount)	0	[3]
Range (Maximum $ Amount)	2.1	[3]
Weighted Average ($ Amount)	0.5	[3]
Level 3 [Member] | Long-lived assets held for sale [Member] | Fair value of property | Sales Price [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum $ Amount)	0	[3]
Range (Maximum $ Amount)	1.6	[3]
Weighted Average ($ Amount)	0.2	[3]
Level 3 [Member] | Long-lived assets held for sale [Member] | Fair value of property | Adjustments For Market/ Property Conditions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Minimum $ Amount)	0	[3]
Range (Maximum $ Amount)	0.2	[3]
Weighted Average ($ Amount)	$ 0.1	[3]

[1] All Level 3, except for $32 million included in Loans held for sale which is categorized as Level 2 as of June 30, 2012.

[2] (b) The assumed yield spread over benchmark curve for each instrument is generally intended to incorporate non-interest-rate risks such as credit and liquidity risks.

[3] (a) Where dollar amounts are disclosed, the amounts represent the lowest and highest fair value of the respective assets in the population except for adjustments for market/property conditions which represents the range of adjustments to individual properties.