Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common stock dividends per share, declared	$ 0.80	$ 0.77	$ 0.74
Series A 3% Preferred Stock [Member]
Preferred stock dividends per share, declared	$ 3.00	$ 3.00	3.00
Preferred stock, dividend percentage	3.00%	3.00%
Series B-1 8.48% Preferred Stock [Member]
Preferred stock dividends per share, declared	$ 8.48	$ 8.48	$ 8.48
Preferred stock, dividend percentage	8.48%	8.48%