Consolidated Statements Of Shareholder's Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Common dividends declared, per share (in dollars per share)	$ 0.6	$ 0.56	$ 0.54