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CAPITAL STOCK (Details) $ / shares in Units, $ in Millions | 2 Months Ended | 3 Months Ended | 12 Months Ended |  |  |  |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Feb. 21, 2013 $ / shares shares | Dec. 31, 2015 USD ($) $ / shares shares | Sep. 30, 2015 USD ($) | Jun. 30, 2015 USD ($) | Dec. 31, 2014 USD ($) $ / shares shares | Sep. 30, 2014 USD ($) | Jun. 30, 2014 USD ($) | Mar. 31, 2014 USD ($) | Feb. 11, 2013 | Dec. 31, 2015 USD ($) $ / shares shares | Dec. 31, 2014 USD ($) $ / shares shares | Dec. 31, 2013 USD ($) | Jan. 04, 2016 shares | Nov. 02, 2015 $ / shares | Aug. 03, 2015 $ / shares | May. 01, 2015 $ / shares | Feb. 02, 2015 $ / shares | Jan. 26, 2015 $ / shares | Dec. 03, 2014 $ / shares | Nov. 03, 2014 $ / shares | Sep. 02, 2014 $ / shares | Aug. 01, 2014 $ / shares | Jun. 03, 2014 $ / shares | Mar. 03, 2014 $ / shares | Mar. 01, 2013 $ / shares
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depositary Share Interest in a Share of 7% Series A Mandatory Convertible Preferred Stock, Class A |  |  |  |  |  |  |  |  |  | 0.025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Par or Stated Value Per Share | $ / shares |  | $ 0.125 |  |  | $ 0.125 |  |  |  |  | $ 0.125 | $ 0.125 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Trading Day Window Determining Number of Common Shares Issuable on Conversion |  |  |  |  |  |  |  |  |  | 20 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of Series A, Mandatory Convertible Preferred Stock, Class A | $ |  |  |  |  |  |  |  |  |  | $ 0.0 | $ 0.0 | $ 709.4 |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends, Preferred Stock | $ |  |  |  |  |  |  |  |  |  | $ 38.4 | $ 51.2 | 48.7 |  |  |  |  |  |  |  |  |  |  |  |  |
Common shares, issued (in shares) |  | 159,546,224 |  |  | 159,546,224 |  |  |  |  | 159,546,224 | 159,546,224 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of common shares | $ |  |  |  |  |  |  |  |  |  | $ 0.0 | $ 0.0 | 285.3 |  |  |  |  |  |  |  |  |  |  |  |  |
Elimination of Dividend | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.15 |  |  |  |  |  |  |
Over Allotment Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common shares, issued (in shares) | 1,350,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred Class A [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series A Mandatory Convertible Preferred Stock, Class A, Percentage |  |  |  |  |  |  |  |  |  | 7.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred Stock, Liquidation Preference Per Share | $ / shares |  | $ 1,000 |  |  | $ 1,000 |  |  |  |  | $ 1,000 | $ 1,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends payable, per share | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 17.5000 | $ 0.44 | $ 17.50 | $ 0.44 |  |  | $ 17.5000 |  | $ 0.44 |  |  |
Dividends, Preferred Stock | $ |  | $ 0.0 | $ 25.6 | $ 0.0 | $ 12.8 | $ 12.8 | $ 12.8 | $ 12.8 |  | $ 38.4 | $ 51.2 | $ 48.7 |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of common shares, public offering (in shares) | 731,250 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Closing price per share (in usd per share) | $ / shares | $ 25 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends payable, per share | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.150 |  | $ 0.150 |  | $ 0.150 | $ 0.15 | $ 0.15
Percentage increase (decrease) in dividends payable |  |  |  |  |  |  |  |  | 76.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of common shares, public offering (in shares) | 10,350,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common shares, issued (in shares) | 9,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Closing price per share (in usd per share) | $ / shares | $ 29.00 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Shares Issued upon Conversion |  | 28.1480 |  |  |  |  |  |  |  | 28.1480 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Shares Issued Upon Conversion per Depositary Share |  | 0.7037 |  |  |  |  |  |  |  | 0.7037 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Shares Issued upon Conversion |  | 34.4840 |  |  |  |  |  |  |  | 34.4840 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depositary Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depositary Share Offering included in Depositary Share Issuance | 27,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Shares included in Depositary Share Issuance due to Exercise of | 2,250,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred Stock, Liquidation Preference Per Share | $ / shares |  | $ 25 |  |  |  |  |  |  |  | $ 25 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends payable, per share | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.44 | $ 17.5000 | $ 0.44 | $ 17.5000 |  |  | $ 0.44 |  | $ 17.5000 |  |  |
Issuance of common shares, public offering (in shares) | 29,250,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Conversion of Preferred Stock [Member] | Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Common Shares Issued Upon Conversion in Lieu of Dividend |  |  |  |  |  |  |  |  |  |  |  |  | 1,300,000 |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Shares Issued upon Conversion |  |  |  |  |  |  |  |  |  |  |  |  | 0.9052 |  |  |  |  |  |  |  |  |  |  |  |
Common shares, issued (in shares) |  |  |  |  |  |  |  |  |  |  |  |  | 26,500,000 |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Common Shares Issued Upon Conversion |  |  |  |  |  |  |  |  |  |  |  |  | 25,200,000 |  |  |  |  |  |  |  |  |  |  |  |
Conversion of Preferred Stock [Member] | Common Stock [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock, Shares Issued upon Conversion |  |  |  |  |  |  |  |  |  |  |  |  | 0.8621 |  |  |  |  |  |  |  |  |  |  |  |

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