COMMON STOCK - Accelerated Share Repurchase (Details) $ / shares in Units, shares in Millions, $ in Millions		1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 19, 2015	Aug. 31, 2013 USD ($) $ / shares shares	Oct. 31, 2013 $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Accelerated Share Repurchase
Amount Paid | $				$ 280.1	$ 300.9	$ 496.9
Common Stock
Accelerated Share Repurchase
Conversion ratio of stock split	2
August 2013
Accelerated Share Repurchase
Amount Paid | $		$ 250.0
Shares Received (in shares) | shares		3.1	3.5
Initial Delivery, Price per Share (in dollars per share) | $ / shares		$ 72.39
Value of Shares as % of Contract Value		90.00%
Final Settlement, Average Price per Share (in dollars per share) | $ / shares			$ 71.24