Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Stock option exercises/stock unit conversions (shares)	774,799	908,921
Treasury stock, shares, acquired	1,135,435	0
Cash dividends declared on preferred stock, per share	$ 1.01	$ 1.01
Cash dividends declared on common stock, per share	$ 1.68	$ 1.61