Fair Value (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Percentage of bank issuers are public companies	27.00%
Probability of default, number of basis points for years 1 through 5			0.30%
Probability of default, increase to number of base points for each year from year 2 to 5			0.48%
Weighted average assumed loss rate on deferring collateral	24.00%		24.00%		26.00%	26.00%
Net gains on sale of OREO properties	$ (5,509,000)	$ (14,363,000)	$ (13,341,000)	$ (34,113,000)
Highest Quality/Most Over-Collateralized Insurance-Only Tranches Discount Rate [Member]
Derivatives, Fair Value [Line Items]
Valuations for bank and insurance tranches utilized a discount rate range of LIBOR	3.75%
Lowest Credit Quality Tranche Discount Rate [Member]
Derivatives, Fair Value [Line Items]
Valuations for bank and insurance tranches utilized a discount rate range of LIBOR	26.00%
AAA [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	6.00%
BBB [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	20.00%
A-Rated Bonds [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	12.00%
OREO Properties [Member]
Derivatives, Fair Value [Line Items]
Net gains on sale of OREO properties	2,900,000	5,500,000	5,800,000	11,000,000
Transfer of Other Real Estate			84,700,000	145,300,000
Impairment of OREO properties	(3,200,000)	(9,900,000)	(3,900,000)	(14,800,000)
Minimum [Member]
Derivatives, Fair Value [Line Items]
Probability of default, minimum number of basis points for year six			0.65%
Minimum [Member] | Highest Quality/Most Over-Collateralized Insurance-Only Tranches Discount Rate [Member]
Derivatives, Fair Value [Line Items]
Valuations for bank and insurance tranches utilized a discount rate range of LIBOR	6.60%
Best [Member]
Derivatives, Fair Value [Line Items]
Percentage of resulting five-year PDs	2.18%		2.18%
Worst [Member]
Derivatives, Fair Value [Line Items]
Percentage of resulting five-year PDs	100.00%		100.00%
First Priority Original AAA-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	6.60%		6.60%
First Priority Original AAA-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	7.60%		7.60%
First Priority Original AAA-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	6.70%		6.70%
Lower Priority Original AAA-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	6.60%		6.60%
Lower Priority Original AAA-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	8.30%		8.30%
Lower Priority Original AAA-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	7.00%		7.00%
Original A-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	6.80%		6.80%
Original A-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	21.90%		21.90%
Original A-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	13.60%		13.60%
Original BBB-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	10.40%		10.40%
Original BBB-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	26.00%		26.00%
Original BBB-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	22.50%		22.50%
Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,952,688,000		1,952,688,000			1,991,915,000
Level 2 [Member] | AFS securities [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	2,000,000,000		2,000,000,000
Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,005,073,000		1,005,073,000			1,078,948,000
Level 3 [Member] | Municipal Securities [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	16,000,000		16,000,000
Level 3 [Member] | AFS securities [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,000,000,000		1,000,000,000
Level 3 [Member] | Other (Including ABS CDOs) [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	30,000,000		30,000,000
Third Party Pricing Service [Member] | Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,800,000,000		1,800,000,000
Third Party Pricing Service [Member] | Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	53,000,000		53,000,000
Licensed Internal Third Party [Member] | Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	905,000,000		905,000,000
Market Corroborative Data [Member] | Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	6,000,000		6,000,000
Market Corroborative Data [Member] | Level 2 [Member] | FAMC Securities [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	$ 143,000,000		$ 143,000,000