Consolidated Statements of Equity (Parentheticals) - $ / shares	3 Months Ended			12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retained Earnings [Abstract]
Dividends declared on common stock (Per share)	$ 0.46	$ 0.42	$ 0.37	$ 1.84	$ 1.72	$ 1.53