Fair Value (Fair Value Measurements- Nonrecurring Quantitative Information) (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	$ 888	[1]
Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	57	[1]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	880		1,081	[1]
Level 3 [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	392	[2]
Level 3 [Member] | Nonaccrual Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	173	[1]	253	[1]
Level 3 [Member] | Nonaccrual Loans [Member] | Appraised Value / Sales Price | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	128
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]
Nonrecurring Assets - Fair Value	45	[3]
Range (Minimum % or bps amount)	1.80%	[3]
Range (Maximum % or bps amount)	98.30%	[3]
Weighted Average (% or bps amount)	58.60%	[3]
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)	0.25%	[4]
Range (Maximum % or bps amount)	2.35%	[4]
Weighted Average (% or bps amount)	1.19%	[4]
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)	0.80%
Range (Maximum % or bps amount)	2.60%
Weighted Average (% or bps amount)	1.70%
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	394	[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)	5.30%
Range (Maximum % or bps amount)	20.60%
Weighted Average (% or bps amount)	6.90%
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)	5.40%
Range (Maximum % or bps amount)	7.90%
Weighted Average (% or bps amount)	7.60%
Level 3 [Member] | OREO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	242	[1]	223	[1]
Level 3 [Member] | OREO [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	242
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	22	[1]	17	[1]
Level 3 [Member] | Long Lived Assets Held For Sale [Member] | Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	$ 22

[1] All Level 3, except for $8 million included in Loans held for sale which is categorized as Level 2 as of September 30, 2012.

[2] Other includes nonaccrual loans of $128 million, OREO and foreclosed assets of $242 million and Long-lived assets held for sale of $22 million as of September 30, 2012. The fair value of these assets are determined based on appraised value or sales price, the range of which is not meaningful to disclose.

[3] The fair value of nonaccrual loans included in this line item is determined based on internal loss rates. Nonaccrual loans where the fair value is determined based on the appraised value or sales price is included within Other, below.

[4] 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.