Investment Securities AFS Gross Unrealized Losses (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (1,224)	$ (82,852)
Unrealized losses on available for sale securities, 12 months or more	(62,712)	(25,182)
Total unrealized losses on available for sale securities	(63,936)	(108,034)
Fair value of unrealized losses on available for sale securities, less than 12 months	288,904	2,386,847
Fair value of unrealized losses on available for sale securities, 12 months or more	1,858,193	467,340
Total fair value of unrealized losses on available for sale securities	2,147,097	2,854,187
Obligations of state and political subdivisions (municipal securities) [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(11)	(1,525)
Unrealized losses on available for sale securities, 12 months or more	(91)	(8)
Total unrealized losses on available for sale securities	(102)	(1,533)
Fair value of unrealized losses on available for sale securities, less than 12 months	5,281	47,044
Fair value of unrealized losses on available for sale securities, 12 months or more	9,066	273
Total fair value of unrealized losses on available for sale securities	14,347	47,317
Number of available for sale securities in a continuous unrealized loss position less than twelve months	13	113
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	21	1
Government-Sponsored Enterprise (GSE) [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(131)	(57,393)
Unrealized losses on available for sale securities, 12 months or more	(40,020)	(21,186)
Total unrealized losses on available for sale securities	(40,151)	(78,579)
Fair value of unrealized losses on available for sale securities, less than 12 months	47,505	1,887,784
Fair value of unrealized losses on available for sale securities, 12 months or more	1,452,736	421,082
Total fair value of unrealized losses on available for sale securities	1,500,241	2,308,866
Number of available for sale securities in a continuous unrealized loss position less than twelve months	8	106
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	63	15
Private Label [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	0	(37)
Unrealized losses on available for sale securities, 12 months or more	(1)	0
Total unrealized losses on available for sale securities	(1)	(37)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	2,105
Fair value of unrealized losses on available for sale securities, 12 months or more	34	35
Total fair value of unrealized losses on available for sale securities	34	2,140
Number of available for sale securities in a continuous unrealized loss position less than twelve months	0	2
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	2	1
GNMA commercial mortgage-related securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(1,081)	(23,854)
Unrealized losses on available for sale securities, 12 months or more	(22,600)	(3,988)
Total unrealized losses on available for sale securities	(23,681)	(27,842)
Fair value of unrealized losses on available for sale securities, less than 12 months	216,723	443,462
Fair value of unrealized losses on available for sale securities, 12 months or more	396,357	45,950
Total fair value of unrealized losses on available for sale securities	613,080	489,412
Number of available for sale securities in a continuous unrealized loss position less than twelve months	9	19
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	15	1
Asset-backed Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(1)
Unrealized losses on available for sale securities, 12 months or more	0
Total unrealized losses on available for sale securities	(1)
Fair value of unrealized losses on available for sale securities, less than 12 months	19,395
Fair value of unrealized losses on available for sale securities, 12 months or more	0
Total fair value of unrealized losses on available for sale securities	19,395
Number of available for sale securities in a continuous unrealized loss position less than twelve months	2
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	0
Other Debt And Other Equity Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	0	(43)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	0	(43)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	6,452
Fair value of unrealized losses on available for sale securities, 12 months or more	0	0
Total fair value of unrealized losses on available for sale securities	$ 0	$ 6,452
Number of available for sale securities in a continuous unrealized loss position less than twelve months	0	5
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	0	0