Consolidated Statement of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Consolidated Statement of Comprehensive Income [Abstract]
Net income	$ 233,380	$ 322,358	$ 439,843	$ 528,631
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	49,289	(33,550)	69,371	(27,892)
Reclassification to income for amortization of gains on terminated cash flow hedges	(42)	(71)	(112)	(141)
Foreign currency translation adjustment	(533)	196	(131)	196
Defined benefit plans liability adjustment	4,695	2,177	9,464	4,288
Total other comprehensive income	53,409	(31,248)	78,592	(23,549)
Total comprehensive income	$ 286,789	$ 291,110	$ 518,435	$ 505,082