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Equity (Details Textual) - USD ($) shares in Thousands, $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2016 | Jun. 30, 2015 | Mar. 31, 2011
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 8,000 |  |  |  |  |
Equity (Textual) |  |  |  |  |  |
Authorized amount of share repurchases under the 2015 Share Repurchase Program |  |  |  | $ 5,000.0 | $ 5,000.0 |
Repurchase of common stock, shares | 3,300 | 16,800 | 2,900 |  |  |
Repurchase of common stock, value | $ 1,000.0 | $ 5,000.0 | $ 886.8 |  |  |
Common stock shares authorized for repurchase | 1,300 |  |  |  |  | 20,000
Series A |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 1,750 |  |  |  |  |
Series X junior participating |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 1,000 |  |  |  |  |
Undesignated |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 5,250 |  |  |  |  |

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- Definition The cash outflow to reacquire common stock during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
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