STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 119,030	$ 109,790	$ 99,195
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	133,023	125,722	144,758
Deferred income taxes	63,789	49,935	62,205
Share-based compensation expense	9,187	7,613	0
Provision for doubtful accounts	4,520	7,195	5,460
Changes in assets and liabilities:
Accounts receivable	105,886	23,044	(102,142)
Materials and supplies	(5,814)	10,868	(1,668)
Income Tax Receivable	4,923	(43,800)	0
Natural gas in storage	43,147	(19,172)	(63,139)
Asset removal costs	(51,608)	(47,125)	(46,567)
Affiliate payable	0	0	(8,140)
Accounts payable	(59,635)	(6,881)	37,241
Accrued interest	1	18,743	(1)
Accrued taxes other than income	(7,493)	12,316	2,449
Accrued Liabilities	5,451	21,228	(5,443)
Customer deposits	322	2,643	(727)
Regulatory assets and liabilities	50,658	30,067	29,436
Employee benefit obligation	(15,033)	(10,102)	0
Other assets and liabilities	(6,147)	(45,421)	1,291
Cash provided by operating activities	394,207	246,663	154,208
Investing activities
Capital expenditures	(294,320)	(297,103)	(292,080)
Proceeds from sale of assets	0	0	1,327
Cash used in investing activities	(294,320)	(297,103)	(290,753)
Financing activities
Settlement of short-term notes payable to ONEOK, net	0	0	150,851
Borrowings on notes payable, net	(29,500)	42,000	0
Repurchase of common stock	(24,122)	0	0
Issuance of debt, net of discounts	0	1,199,994	0
Long-term debt financing costs	0	(11,087)	0
Cash payment to ONEOK upon separation	0	(1,130,000)	0
Issuance of common stock	7,051	2,001	0
Dividends paid	(62,826)	(43,696)	0
Repayment of long-term debt	0	0	(206)
Distributions to ONEOK	0	0	(14,969)
Cash provided by financing activities	(109,397)	59,212	135,676
Change in cash and cash equivalents	(9,510)	8,772	(869)
Cash and cash equivalents at beginning of period	11,943	3,171	4,040
Cash and cash equivalents at end of period	2,433	11,943	3,171
Supplemental cash flow information:
Cash paid for interest, net of amounts capitalized	42,980	21,066	0
Cash paid to ONEOK for interest, net of amounts capitalized	0	0	61,366
Cash (received) paid for income taxes, net	(5,423)	44,603	0
Cash paid to ONEOK for income taxes	$ 0	$ 0	$ 67