Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Investment [Line Items]
Amortized Cost	$ 8,874,540		$ 9,258,525
Fair Value	8,915,680		9,522,248
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	498,226		399,971
Fair Value	505,696		438,759
Weighted Average Yield	1.05%	[1]
U.S. Government And Federal Agency Obligations [Member] | Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	274,859
Fair Value	293,742
Weighted Average Yield	1.71%	[1]
U.S. Government And Federal Agency Obligations [Member] | Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	150,790
Fair Value	152,277
Weighted Average Yield	0.51%	[1]
U.S. Government And Federal Agency Obligations [Member] | Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	72,577
Fair Value	59,677
Weighted Average Yield	(0.31%)	[1]
Government-sponsored enterprise obligations [Member]
Investment [Line Items]
Amortized Cost	766,802		467,063
Fair Value	741,766		471,574
Weighted Average Yield	1.65%
Government-sponsored enterprise obligations [Member] | Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	30,159
Fair Value	30,437
Weighted Average Yield	1.58%
Government-sponsored enterprise obligations [Member] | Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	446,124
Fair Value	444,504
Weighted Average Yield	1.57%
Government-sponsored enterprise obligations [Member] | Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	143,535
Fair Value	132,930
Weighted Average Yield	1.59%
Government-sponsored enterprise obligations [Member] | Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	146,984
Fair Value	133,895
Weighted Average Yield	1.97%
State and municipal obligations [Member]
Investment [Line Items]
Amortized Cost	1,624,195		1,585,926
Fair Value	1,619,171		1,615,707
Weighted Average Yield	2.42%
State and municipal obligations [Member] | Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	141,912
Fair Value	143,357
Weighted Average Yield	2.70%
State and municipal obligations [Member] | Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	734,238
Fair Value	756,570
Weighted Average Yield	2.64%
State and municipal obligations [Member] | Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	562,959
Fair Value	543,749
Weighted Average Yield	2.21%
State and municipal obligations [Member] | Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	185,086
Fair Value	175,495
Weighted Average Yield	1.94%
Agency mortgage-backed securities [Member]
Investment [Line Items]
Amortized Cost	2,743,803		3,248,007
Fair Value	2,772,338		3,380,955
Weighted Average Yield	2.74%
Non-agency mortgage-backed securities [Member]
Investment [Line Items]
Amortized Cost	236,595		224,223
Fair Value	246,983		237,011
Weighted Average Yield	4.51%
Asset-backed securities [Member]
Investment [Line Items]
Amortized Cost	2,847,368		3,152,913
Fair Value	2,844,071		3,167,394
Weighted Average Yield	0.88%
Total mortgage and asset-backed securities [Member]
Investment [Line Items]
Amortized Cost	5,827,766		6,625,143
Fair Value	5,863,392		6,785,360
Weighted Average Yield	1.90%
Other debt securities [Member]
Investment [Line Items]
Amortized Cost	147,581		174,727
Fair Value	141,757		177,752
Other debt securities [Member] | Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	7,695
Fair Value	7,719
Other debt securities [Member] | Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	49,697
Fair Value	50,125
Other debt securities [Member] | Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	90,189
Fair Value	83,913
Equity securities [Member]
Investment [Line Items]
Amortized Cost	9,970		5,695
Fair Value	$ 43,898		$ 33,096

[1] Rate does not reflect inflation adjustment on inflation-protected securities