DEBT Line of Credit Facility (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Line of credit facility disclosures
Line of Credit Facility, Maximum Borrowing Capacity	$ 750.0
Line of credit, potential maximum with Company's request and lender consent	$ 1,000.0
Credit Facility covenant, consolidated total debt to consolidated EBITDA ratio, numerator(cannot exceed)	3.5
Credit Facility covenant, consolidated total debt to consolidated EBITDA ratio, denominator	1.00
Credit Facility covenant, consolidated EBITDA to consolidated interest expense ratio, numerator (cannot be less)	3.00
Credit Facility covenant, consolidated EBITDA to consolidated interest expense ratio, denominator	1.00
Description of interest rate basis	LIBOR
Credit facility, commitment fee percentage	0.125%
Long-term Line of Credit	$ 750.0
Lower limit
Line of credit facility disclosures
Range of margin added to base rate (as a percent)	0.00%
Upper limit
Line of credit facility disclosures
Range of margin added to base rate (as a percent)	1.375%
Revolving Credit Facility [Member]
Line of credit facility disclosures
Proceeds from Lines of Credit	$ 0.0	$ 446.0
Line of Credit Facility, Outstanding at End of Period	$ 0.0