Parent Company Financial Information (Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net cash used in operating activities	$ 596,067	$ 464,352	$ 380,341
Other, net	(14,243)	48,919	34,916
Net cash provided by (used in) investing activities	(3,436,254)	(2,579,901)	(1,268,562)
Net change in short-term funds borrowed	480,282	102,764	(96,125)
Repayments of long-term debt	(280,120)	(287,752)	(1,223,275)
Debt Extinguishment Costs Paid	(353)	(2,530)	(35,435)
Payments for Repurchase of Common Stock	(97,240)	(6,681)	(5,589)
Other, net	2,227	1,441	2,030
Net cash provided by (used in) financing activities	2,779,195	2,071,926	557,106
Net increase (decrease) in cash and due from banks	(60,992)	(43,623)	(331,115)
Cash and Due From Banks - Beginning of Year	737,327	798,319	841,942	$ 1,173,057
Interest paid	83,338	101,623	152,783
Other Noncash Income (Expense)	3,352	(19,712)	(23,287)
Parent Company [Member]
Net income (loss) applicable to controlling interest	469,050	309,471	398,462
Undistributed net losses (income) of consolidated subsidiaries	(226,641)	(97,781)	(93,163)
Net cash used in operating activities	211,714	290,405	499,001
Net decrease (increase) in interest-bearing deposits	347,118	132,267	(1,007,844)
Collection of advances to subsidiaries	60	56,000	15,000
Advances to subsidiaries	0	(41,000)	(30,060)
Proceeds from Sale and Maturity of Marketable Securities	3,878	124,419	372,357
Purchases of investment securities	0	(46,851)	0
Decrease (increase) of investment in subsidiaries	0	15,000	6,310
Other, net	7,342	4,010	24,319
Net cash provided by (used in) investing activities	358,398	243,845	(619,918)
Repayments of long-term debt	(279,948)	(271,120)	(1,147,641)
Debt Extinguishment Costs Paid	(353)	(135)	(35,435)
Proceeds from issuance of common stock and warrants	25,072	22,392	526,438
Cash paid for preferred stock redemption	(126,144)	(175,669)	0
Payments for Repurchase of Common Stock	(97,240)	(6,681)	(5,589)
Dividends paid on preferred stock	(50,098)	(62,857)	(64,868)
Dividends paid on common stock	57,753	45,198	31,262
Other, net	0	(381)	(30)
Net cash provided by (used in) financing activities	(586,464)	(539,649)	(758,387)
Net increase (decrease) in cash and due from banks	(16,352)	(5,399)	(879,304)
Cash and Due From Banks - Beginning of Year	2,023	18,375	23,774	$ 903,078
Interest paid	35,000	51,400	100,600
Extinguishment of Debt, Amount	353	135	44,422
Other Noncash Income (Expense)	$ (31,048)	$ 78,580	$ 149,280