Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fixed maturity securities:
Available for sale securities, amortized cost	$ 48,238,946	$ 46,131,190
Stockholders' equity:
Preferred stock, par value (dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	16,000	0
Preferred stock, shares outstanding	16,000	0
Preferred stock, aggregate liquidation preference	$ 400,000
Common stock, par value (dollars per share)	$ 1	$ 1
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	91,107,555	90,369,229
Common stock, shares outstanding	91,107,555	90,369,229
Common stock, shares held in treasury	1,344,193	1,535,960