Equity Equity (Common Stock Changes in Number of Shares Issued, Held in Treasury and Oustanding) (Details) - shares		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Common Stock, Shares, Issued		79,137,758	79,137,758
Treasury Stock, Shares, Acquired		1,356,892	4,145,440	2,530,608
Common Stock Issuable [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		79,137,758	79,137,758	79,137,758	79,137,758
Stock Based Compensation Shares	[1]	0	0	0
Treasury Stock, Shares, Acquired		0	0	0
Common Stock Held In Treasury [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		14,835,256	13,933,232	10,364,797	8,369,540
Stock Based Compensation Shares	[1]	(454,868)	(577,005)	(535,351)
Treasury Stock, Shares, Acquired		1,356,892	4,145,440	2,530,608
Common Stock Outstanding [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		64,302,502	65,204,526	68,772,961	70,768,218
Stock Based Compensation Shares	[1]	454,868	577,005	535,351
Treasury Stock, Shares, Acquired		(1,356,892)	(4,145,440)	(2,530,608)

[1] Represents net shares issued from treasury pursuant to the Company’s stock-based compensation programs.