EQUITY AND EARNINGS PER SHARE - Activity in Outstanding Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, Outstanding options (in shares)	18,502,188.000	13,196,610
Options granted (in shares)	5,799,166	5,654,578
Options exercised (in shares)	(15,803,216)	0
Options expired unexercised (in shares)	0	(349,000)
Ending balance, Outstanding options (in shares)	8,498,138.000	18,502,188.000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, options granted (in dollars per share)	$ 17.23	$ 14.50
Weighted average exercise price, options exercised (in dollars per share)	$ 14.30	$ 0.00
Option exercised (in shares)	15,803,216	0
Intrinsic value of options exercised	$ 68.9

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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