Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

Schedule of Stockholders Equity

The following table summarizes the changes in Common Stock and Treasury Stock:

	Common Stock		Treasury Stock
Balance at December 31, 2011	199,751,070		123,586,842
Issuance of common stock	1,118,089		(1,118,089	)
Conversions to common stock	14,888		(14,888	)
Balance at December 31, 2012	200,884,047		122,453,865
Issuance of common stock	1,163,668		(1,163,668	)
Conversions to common stock	34,807		(34,807	)
Balance at December 31, 2013	202,082,522		121,255,390
Repurchases of common stock	(1,863,262	)	1,863,262
Issuance of common stock	781,032		(781,032	)
Conversions to common stock	27,672		(27,672	)
Balance at December 31, 2014	201,027,964		122,309,948