Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Statement of Stockholders' Equity [Abstract]
Stock option exercises (shares)	1,249,874	197,961
Issuance of preferred stock (shares)	6,000,000
Purchase of treasury stock, shares	2,236,748
Cash dividends declared on preferred stock, per share	$ 0.78
Cash dividends, per share	$ 1.48	$ 1.42