Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pledged securities that can be sold or repledged	$ 200,339	$ 487,365
Investment securities, available for sale, amortized cost	6,258,276	8,869,423
Investment securities, held to maturity, fair value	2,699,206	3,255,483
Equity and other securities, cost	$ 487,041	$ 677,187
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	159,741,898	159,765,044
Common stock issuable, shares	21,534	24,563
Treasury stock, common shares	29,174,402	21,255,275
Series A Series C Series And E Preferred Stock [Member]
Preferred stock, shares issued	350,000	731,500
Preferred stock, shares outstanding	350,000	731,500
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Series F And Series G Preferred Stock [Member]
Preferred stock, shares issued	90,000	50,000
Preferred stock, shares outstanding	90,000	50,000
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000