SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 15,295	$ 37,193	$ 332,371	$ 248,875
Accounts receivable, net	934,664	1,202,951
Materials and supplies	113,831	90,301
Natural gas and natural gas liquids in storage	285,776	342,293
Other current assets	57,286	53,008
Total current assets	1,433,687	1,764,458
Property, plant and equipment
Property, plant and equipment	16,363,716	15,559,667
Accumulated depreciation and amortization	3,059,799	2,861,541
Net property, plant and equipment	13,303,917	12,698,126
Investments and other assets
Investments	986,979	1,003,156
Other assets	170,124	180,830
Total investments and other assets	2,176,116	2,383,353
Total assets	16,913,720	16,845,937	16,672,923
Current liabilities
Current maturities of long-term debt	932,650	432,650
Short-term borrowings	156,000	614,673
Accounts payable	1,027,467	1,140,571
Other current liabilities	184,127	179,971
Total current liabilities	2,572,081	2,667,335
Long-term debt, excluding current maturities	7,091,246	8,091,629
Deferred credits and other liabilities	411,910	401,621
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	6,664,860	5,527,867
Noncontrolling interests in consolidated subsidiaries	173,623	157,485
Total equity	6,838,483	5,685,352	5,565,231	3,428,915
Total liabilities and equity	16,913,720	16,845,937
Reportable Legal Entities \| Parent Issuer & Guarantor
Current assets
Cash and cash equivalents	15,300	37,200	321,000	248,500
Accounts receivable, net	0	0
Materials and supplies		0
Natural gas and natural gas liquids in storage	0	0
Other current assets	11,900	9,800
Total current assets	27,200	47,000
Property, plant and equipment
Property, plant and equipment	137,200	128,300
Accumulated depreciation and amortization	89,200	86,400
Net property, plant and equipment	48,000	41,900
Investments and other assets
Investments	5,872,900	5,752,100
Intercompany notes receivable	3,679,200	2,926,900
Other assets	233,000	416,900
Total investments and other assets	9,785,100	9,095,900
Total assets	9,860,300	9,184,800
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	156,000	614,700
Accounts payable	6,200	12,000
Other current liabilities	71,200	65,900
Total current liabilities	233,400	692,600
Intercompany debt	0	0
Long-term debt, excluding current maturities	2,727,000	2,726,400
Deferred credits and other liabilities	235,000	237,900
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	6,664,900	5,527,900
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	6,664,900	5,527,900
Total liabilities and equity	9,860,300	9,184,800
Reportable Legal Entities \| Subsidiary Issuer & Guarantor
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Materials and supplies		0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	1,300
Total current assets	0	1,300
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	3,243,000	3,133,700
Intercompany notes receivable	8,140,900	8,627,800
Other assets	0	200
Total investments and other assets	11,383,900	11,761,700
Total assets	11,383,900	11,763,000
Current liabilities
Current maturities of long-term debt	925,000	425,000
Short-term borrowings	0	0
Accounts payable	0	0
Other current liabilities	85,000	85,000
Total current liabilities	1,010,000	510,000
Intercompany debt	0	0
Long-term debt, excluding current maturities	4,339,200	5,336,400
Deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	6,034,700	5,916,600
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	6,034,700	5,916,600
Total liabilities and equity	11,383,900	11,763,000
Reportable Legal Entities \| Guarantor Subsidiary
Current assets
Cash and cash equivalents	0	0	11,400	400
Accounts receivable, net	0	0
Materials and supplies		0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	8,795,000	8,058,400
Intercompany notes receivable	2,588,900	3,703,100
Other assets	0	0
Total investments and other assets	11,383,900	11,761,500
Total assets	11,383,900	11,761,500
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany debt	8,140,900	8,627,800
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	3,243,000	3,133,700
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	3,243,000	3,133,700
Total liabilities and equity	11,383,900	11,761,500
Reportable Legal Entities \| Combined Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	934,700	1,203,000
Materials and supplies		90,300
Natural gas and natural gas liquids in storage	285,800	342,300
Other current assets	186,000	80,600
Total current assets	1,406,500	1,716,200
Property, plant and equipment
Property, plant and equipment	16,226,500	15,431,300
Accumulated depreciation and amortization	2,970,600	2,775,100
Net property, plant and equipment	13,255,900	12,656,200
Investments and other assets
Investments	795,400	803,000
Intercompany notes receivable	0	0
Other assets	1,006,900	1,007,400
Total investments and other assets	1,802,300	1,810,400
Total assets	16,464,700	16,182,800
Current liabilities
Current maturities of long-term debt	7,700	7,700
Short-term borrowings	0	0
Accounts payable	1,021,300	1,128,600
Other current liabilities	299,700	328,400
Total current liabilities	1,328,700	1,464,700
Intercompany debt	6,268,100	6,630,000
Long-term debt, excluding current maturities	25,000	28,800
Deferred credits and other liabilities	227,700	208,100
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	8,441,600	7,693,700
Noncontrolling interests in consolidated subsidiaries	173,600	157,500
Total equity	8,615,200	7,851,200
Total liabilities and equity	16,464,700	16,182,800
Reportable Legal Entities \| Total
Current assets
Cash and cash equivalents	15,300	37,200	332,400	248,900
Accounts receivable, net	934,700	1,203,000
Materials and supplies		90,300
Natural gas and natural gas liquids in storage	285,800	342,300
Other current assets	197,900	91,700
Total current assets	1,433,700	1,764,500
Property, plant and equipment
Property, plant and equipment	16,363,700	15,559,600
Accumulated depreciation and amortization	3,059,800	2,861,500
Net property, plant and equipment	13,303,900	12,698,100
Investments and other assets
Investments	987,000	1,003,200
Intercompany notes receivable	0	0
Other assets	1,189,100	1,380,100
Total investments and other assets	2,176,100	2,383,300
Total assets	16,913,700	16,845,900
Current liabilities
Current maturities of long-term debt	932,700	432,700
Short-term borrowings	156,000	614,700
Accounts payable	1,027,500	1,140,600
Other current liabilities	455,900	479,300
Total current liabilities	2,572,100	2,667,300
Intercompany debt	0	0
Long-term debt, excluding current maturities	7,091,200	8,091,600
Deferred credits and other liabilities	411,900	401,600
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	6,664,900	5,527,900
Noncontrolling interests in consolidated subsidiaries	173,600	157,500
Total equity	6,838,500	5,685,400
Total liabilities and equity	16,913,700	16,845,900
Consolidating Entries
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Materials and supplies		0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	(17,719,300)	(16,744,000)
Intercompany notes receivable	(14,409,000)	(15,257,800)
Other assets	(50,800)	(44,400)
Total investments and other assets	(32,179,100)	(32,046,200)
Total assets	(32,179,100)	(32,046,200)
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany debt	(14,409,000)	(15,257,800)
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	(50,800)	(44,400)
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	(17,719,300)	(16,744,000)
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	(17,719,300)	(16,744,000)
Total liabilities and equity	$ (32,179,100)	$ (32,046,200)

Intercompany Debt

No definition available.

Name:	oke_IntercompanyDebt
Namespace Prefix:	oke_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate of amounts due from managing member, general partner or affiliate more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date more than one year from the balance sheet date.

+ References

No definition available.