Condensed Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical) - $ / shares		3 Months Ended		9 Months Ended
	Aug. 14, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share (in $ per share)	$ 0.55	$ 0.55	$ 0.45	$ 1.45	$ 1.35
Cash dividends declared per preferred share (in $ per share)	$ 1.8125	$ 1.81	$ 1.81	$ 5.44	$ 5.44