SHORT-TERM BORROWINGS (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) Rate
ONEOK Credit Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 300,000,000
Indebtedness To Adjusted EBITDA Maximum	4.0
Indebtedness To Adjusted EBITDA Current	2.1
Line of Credit Facility Letter of Credit Sublimit	$ 50,000,000
Line of Credit Facility Swingline Sublimit	50,000,000
Line Of Credit Facility Option To Increase Borrowing Capacity	$ 500,000,000
Interest rate description	borrowings, if any, will accrue interest at LIBOR plus 145 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 30 basis points
Letters of credit issued	$ 1,100,000
Borrowings outstanding under Partnership Credit Agreement	0
Partnership Credit Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 2,400,000,000
Indebtedness To Adjusted EBITDA Maximum	5.0
Indebtedness To Adjusted EBITDA Current	4.1
Line of Credit Facility Letter of Credit Sublimit	$ 100,000,000
Line of Credit Facility Swingline Sublimit	$ 150,000,000
Interest rate description	borrowings, if any, will accrue at LIBOR plus 117.5 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 20 basis points
Letters of credit issued	$ 14,000,000
Borrowings outstanding under Partnership Credit Agreement	0
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,700,000,000
Indebtedness To Adjusted EBITDA From Acquisitions Maximum	5.5
Acquisition price threshold for increase in permitted debt to EBITDA covenant ratio	$ 25,000,000
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Commercial paper outstanding	694,000,000
Maximum Amount Of Commercial Paper	$ 2,400,000,000
Short-term Debt, Weighted Average Interest Rate | Rate	1.15%