DEBT - Commercial Paper (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2014
Short-term Debt [Line Items]
Short-term borrowings	$ 150,000,000	$ 300,000,000
Commercial Paper
Short-term Debt [Line Items]
Maximum borrowing capacity			$ 2,000,000,000
Maximum amount outstanding during period	500,000,000
Short-term borrowings	$ 150,000,000	$ 300,000,000