DEBT (Convertible Subordinated Notes) (Details)	3 Months Ended
	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($)
Zero Coupon Convertible Subordinated Notes [Line Items]
Number of trading days used to establish contingent cash interest rate on zero-coupon subordinated notes (in days)	five
Payments On Zero Coupon Subordinated Notes	$ 0	$ 22,900,000
Zero-coupon convertible subordinated notes [Member]
Zero Coupon Convertible Subordinated Notes [Line Items]
Minimum contingent cash interest rate on zero-coupon subordinated notes (in hundredths)	0.125%
Stock conversion rate for zero-coupon subordinated notes (per thousand) | shares	13.4108
Principal amount of zero-coupon subordinated notes	$ 1,000,000,000