SUBSEQUENT EVENTS - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions				6 Months Ended	12 Months Ended
	Feb. 16, 2017	Jan. 20, 2017	Apr. 06, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Common stock dividends (in dollars per share)				$ 0.12
Preferred stock dividends					$ 14	$ 7
Series A Preferred Stock
Subsequent Event [Line Items]
Preferred stock, dividend rate			5.50%
Subsequent Event
Subsequent Event [Line Items]
Common stock dividends (in dollars per share)		$ 0.14
Common stock dividends		$ 72
Subsequent Event | Series A Preferred Stock
Subsequent Event [Line Items]
Preferred stock, dividend rate	5.50%
Preferred stock dividend declared (in dollars per share)	$ 27.5
Preferred stock dividends	$ 7