Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash dividends declared on common shares (in usd per share)	$ 0.225	$ 0.180
Series A Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)		1.9375
Series C Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)		0.539063
Series D Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	25	25
Series E Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	$ 0.765626	$ 0.778386