STOCK-BASED COMPENSATION - STOCK-BASED COMPENSATION EXPENSE (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Information related to share based awards
Total stock-based compensation expense	$ 30.2	$ 14.0	$ 16.1
Deferred income tax benefit	12.1	5.6	6.4
Stock-based compensation cost capitalized	0	0	0
Stock Options
Information related to share based awards
Total stock-based compensation expense	2.7	1.8	2.0
Performance Stock Rights
Information related to share based awards
Total stock-based compensation expense	16.8	2.7	5.0
Restricted Share Units
Information related to share based awards
Total stock-based compensation expense	9.9	8.6	8.1
Nonemployee Director Deferred Stock Units
Information related to share based awards
Total stock-based compensation expense	$ 0.8	$ 0.9	$ 1.0

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

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-Name Accounting Standards Codification

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

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Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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