Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net income	$ 491,795	$ 468,532	$ 419,930
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	275,098	273,600	298,996
Goodwill impairment	17,000	12,500	0
Total securities impairment	1,660	180	3,864
Amortization of intangibles	39,208	50,856	60,691
Accretion of discount, loan fees and purchase market adjustments, net	(128,170)	(176,114)	(299,018)
FDIC indemnification expense	55,129	115,049	267,159
Provision for loan losses	193,638	106,301	107,546
Amortization of stock based compensation	4,175	4,515	8,311
Net change in trading account assets	(20,180)	(42,258)	225,850
Net change in trading account liabilities	(8,440)	46,573	(233,745)
Net change in loans held for sale	84,234	13,428	266,356
Deferred tax (benefit) expense	(110,902)	(9,081)	34,130
Investment securities gains, net	(81,656)	(53,042)	(31,371)
(Gain) loss on prepayment of FHLB and other borrowings	8,016	315	(21,775)
Loss on sale of premises and equipment	868	5,906	11,661
(Gain) loss on sale of loans	(22,091)	82	0
Net (gain) loss on sale of other real estate and other assets	508	(1,511)	(8,458)
Loss on disposition	0	981	0
(Increase) decrease in other assets	190,261	(459,288)	18,402
Increase (decrease) in other liabilities	(320,949)	443,712	6,864
Net cash provided by operating activities	669,202	801,236	1,135,393
Investing Activities:
Proceeds from sales of investment securities available for sale	3,369,062	1,114,215	1,126,609
Proceeds from prepayments, maturities and calls of investment securities available for sale	1,564,910	1,382,949	1,968,803
Purchases of investment securities available for sale	(5,856,808)	(4,409,991)	(3,719,792)
Proceeds from prepayments, maturities and calls of investment securities held to maturity	123,188	195,276	212,483
Purchases of investment securities held to maturity	(85,929)	(7,312)	(210,830)
Purchases of trading securities	(4,831,626)	(2,472,209)	0
Proceeds from sales of trading securities	3,548,071	0	0
Net change in loan portfolio	(4,426,260)	(6,799,260)	(5,907,928)
Purchase of premises and equipment	(160,526)	(127,060)	(167,231)
Proceeds from sale of premises and equipment	8,138	19,238	233
Net cash paid in acquisition	(12,567)	(97,566)	0
Proceeds from sales of loans	488,550	107,936	203,958
Payments to FDIC for covered assets	(1,924)	(12,709)	(19,546)
Proceeds from sales of other real estate owned	20,011	25,895	101,677
Net cash used in investing activities	(6,253,710)	(11,080,598)	(6,411,564)
Financing Activities:
Net increase in demand deposits, NOW accounts and savings accounts	3,564,104	5,998,569	2,921,046
Net increase (decrease) in time deposits	1,216,583	741,352	(126,256)
Net increase (decrease) in federal funds purchased and securities sold under agreements to repurchase	(379,349)	276,933	(249,021)
Net increase in other short-term borrowings	1,486,920	2,540,133	1,828
Proceeds from FHLB and other borrowings	5,300,000	2,195,418	425,000
Repayment of FHLB and other borrowings	(4,664,941)	(1,688,797)	(346,347)
Vesting of restricted stock	(3,720)	(4,702)	(5,741)
Restricted stock grants retained to cover taxes	(2,984)	(2,507)	(2,228)
Issuance of preferred stock	229,475	0	0
Issuance of common stock	0	117,000	100,000
Common dividends paid	(95,000)	(102,000)	0
Preferred dividends paid	(2,093)	(2,092)	(2,092)
Net cash provided by financing activities	6,648,995	10,069,307	2,716,189
Net increase (decrease) in cash and cash equivalents	1,064,487	(210,055)	(2,559,982)
Cash and cash equivalents, January 1	3,388,405	3,598,460	6,158,442
Cash and cash equivalents, December 31	$ 4,452,892	$ 3,388,405	$ 3,598,460