Investment Securities Noncredit Related Other Than Temporary Impairment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Noncredit Related Losses On Securities Not Expected To Be Sold [Line Items]
Noncredit-related losses on securities not expected to be sold (recognized in other comprehensive income)	$ 0	$ 21,376
Held-to-maturity Securities [Member]
Noncredit Related Losses On Securities Not Expected To Be Sold [Line Items]
Noncredit-related losses on securities not expected to be sold (recognized in other comprehensive income)	0	16,114
Available-for-sale Securities [Member]
Noncredit Related Losses On Securities Not Expected To Be Sold [Line Items]
Noncredit-related losses on securities not expected to be sold (recognized in other comprehensive income)	$ 0	$ 5,262