Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Stock Issued During Period, Value, New Issues	$ 515,856		$ 515,856
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues			17,617,450
Balance at Dec. 31, 2013	6,464,563	$ 1,003,970	$ 4,179,024	$ 1,473,670	$ (192,101)
Balance (in shares) at Dec. 31, 2013			184,677,696
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	316,648			316,648
Other comprehensive income, net of tax	81,174				81,174
Subordinated debt converted to preferred stock	31	$ 36	$ (5)
Net activity under employee plans and related tax benefits	22,420		$ 22,420
Net activity under employee plans and related tax benefits, shares			603,345
Dividends on preferred stock	(56,841)			(56,841)
Dividends on common stock, $0.16 per share	(23,039)			(23,039)
Change in deferred compensation	1,347			1,347
Balance at Sep. 30, 2014	7,322,159	$ 1,004,006	$ 4,717,295	1,711,785	(110,927)
Balance (in shares) at Sep. 30, 2014			202,898,491
Balance at Dec. 31, 2014	$ 7,369,530	1,004,011	$ 4,723,855	1,769,705	(128,041)
Balance (in shares) at Dec. 31, 2014	203,014,903		203,014,903
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	$ 206,984			206,984
Other comprehensive income, net of tax	111,066				111,066
Subordinated debt converted to preferred stock	104	148	$ (44)
Net activity under employee plans and related tax benefits	32,477		$ 32,477
Net activity under employee plans and related tax benefits, shares			1,263,691
Dividends on preferred stock	(48,567)			(48,567)
Dividends on common stock, $0.16 per share	(32,785)			(32,785)
Change in deferred compensation	(714)			(714)
Balance at Sep. 30, 2015	$ 7,638,095	$ 1,004,159	$ 4,756,288	$ 1,894,623	$ (16,975)
Balance (in shares) at Sep. 30, 2015	204,278,594		204,278,594