Significant Accounting Policy Common Stock Rollforward (Details) - shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock [Roll Forward]
Common Stock, Shares, Outstanding	229,054,236	230,265,463	229,145,736
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	388,772	1,001,873	1,119,727
Common Stock, Shares, Outstanding	229,443,008	229,054,236	230,265,463
Stock Repurchased and Retired During Period, Shares	0	(2,213,100)	0

Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration