Fair Value (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Percentage of bank issuers are public companies	30.00%
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	21.00%		21.00%		24.00%	26.00%
Net gains on sale of OREO properties	$ (309,000)	$ (15,550,000)	$ (13,650,000)	$ (49,663,000)
Principal amount of other real estate owned property sold			126,000,000	217,000,000
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	40.80%
AAA [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	4.00%
BBB [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	29.00%
A-Rated Bonds [Member]
Derivatives, Fair Value [Line Items]
Percentage of difference between rated bonds	14.00%
OREO Properties [Member]
Derivatives, Fair Value [Line Items]
Net gains on sale of OREO properties	5,600,000	2,500,000	11,400,000	13,400,000
Impairment of OREO properties	(3,300,000)	(6,700,000)	(7,200,000)	(21,400,000)
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	4.60%
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	4.60%		4.60%
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	10.40%		10.40%
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	5.10%		5.10%
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	4.60%		4.60%
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	7.30%		7.30%
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	5.20%		5.20%
Original A-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	5.30%		5.30%
Original A-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	25.40%		25.40%
Original A-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	15.60%		15.60%
Original BBB-Rated Bonds Discount Rate [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	13.80%		13.80%
Original BBB-Rated Bonds Discount Rate [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Discount rate range of LIBOR utilized for fair value purposes	40.80%		40.80%
Original BBB-Rated Bonds Discount Rate [Member] | Average [Member]
Derivatives, Fair Value [Line Items]
Discount rate average of LIBOR utilized for fair value purposes	31.50%		31.50%
Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,868,265,000		1,868,265,000			1,991,915,000
Level 2 [Member] | AFS securities [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,900,000,000		1,900,000,000
Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,044,101,000		1,044,101,000			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	29,000,000		29,000,000
Third Party Pricing Service [Member] | Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	1,700,000,000		1,700,000,000
Third Party Pricing Service [Member] | Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	57,000,000		57,000,000
Licensed Internal Third Party [Member] | Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	942,000,000		942,000,000
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	$ 117,000,000		$ 117,000,000