Income Statement [Table] Income Statement [Table] Available-for-sale Securities Available-for-sale Securities [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Property, Plant and Equipment, Net [Abstract] Property, Plant and Equipment, Net [Abstract] Accounts Payable and Accrued Liabilities, Current Accounts Payable and Accrued Liabilities, Current ARO Assets [Domain] ARO Assets [Domain] [Domain] for ARO Assets [Axis] SUPPLEMENTAL INFORMATION: Supplemental Cash Flow Information [Abstract] Operating Lease, Liability, Noncurrent Operating Lease, Liability, Noncurrent Accounting Standards Update [Axis] Accounting Standards Update [Axis] Interest expense, net Interest Expense OPERATING EXPENSES: Operating Expenses [Abstract] Entity Interactive Data Current Entity Interactive Data Current Accrued Environmental Loss Contingencies, Noncurrent Accrued Environmental Loss Contingencies, Noncurrent NET INCOME Net income Net Income (Loss) Attributable to Parent OPERATING REVENUES: Revenues [Abstract] Operating Lease, Right-of-Use Asset Operating Lease, Right-of-Use Asset FINANCING ACTIVITIES: FINANCING ACTIVITIES: [Abstract] FINANCING ACTIVITIES: [Abstract] Document Period End Date Document Period End Date Increase (Decrease) in Other Operating Assets and Liabilities, Net Changes in operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Entity Central Index Key Entity Central Index Key Fixed Income Securities [Member] Fixed Income Securities [Member] Product and Service, Other [Member] Product and Service, Other [Member] Entity Filer Category Entity Filer Category Description of the Business Description of the Business [Line Items] Description of the Business [Line Items] General and administrative Selling, General and Administrative Expense Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Income Statement [Abstract] Income Statement [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Investments, Fair Value Disclosure Investments, Fair Value Disclosure Entity Registrant Name Entity Registrant Name Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Entity Address, State or Province Entity Address, State or Province Other non-current assets, net Other Assets, Noncurrent Property, Plant and Equipment, Net, Total Property, Plant and Equipment, Net Other Liabilities, Noncurrent Other Liabilities, Noncurrent Basis of Presentation and Significant Accounting Policies [Text Block] Basis of Presentation and Significant Accounting Policies [Text Block] Net change in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Related Party Transaction [Axis] Related Party Transaction [Axis] Liabilities, Current [Abstract] Liabilities, Current [Abstract] Entity File Number Entity File Number Stockholders' Equity, Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Operating and maintenance Related Party Transaction, Expenses from Transactions with Related Party Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Amendment Flag Amendment Flag Entity Tax Identification Number Entity Tax Identification Number Related company note activity Repayments of Related Party Debt Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Investment Type [Axis] Investment Type [Axis] Document Fiscal Period Focus Document Fiscal Period Focus Property, plant and equipment Property, Plant and Equipment, Gross Total current assets Assets, Current Equity Securities, FV-NI, Unrealized Gain (Loss) Equity Securities, FV-NI, Unrealized Gain (Loss) Related Party Transaction [Domain] Related Party Transaction [Domain] Equity Securities [Member] Equity Securities [Member] General and administrative Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Inventories Inventory, Net Total operating revenues Revenues Panhandle [Member] Panhandle [Member] Panhandle [Member] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Long-term Debt and Lease Obligation Long-term Debt and Lease Obligation Related Party Transactions [table text block] Schedule of Related Party Transactions [Table Text Block] Document Transition Report Document Transition Report Actuarial gain relating to postretirement benefit plans Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Other Commitments [Line Items] Other Commitments [Line Items] Product and Service [Axis] Product and Service [Axis] Commitments and Contingencies Commitments and Contingencies Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company Entity Current Reporting Status Entity Current Reporting Status Partner Capital Components [Domain] Partner Capital Components [Domain] Stockholders' Equity, Other Stockholders' Equity, Other Statement of Partners' Capital [Abstract] Statement of Partners' Capital [Abstract] Local Phone Number Local Phone Number ASSETS Assets [Abstract] Other Commitments [Table] Other Commitments [Table] Investments [Domain] Investments [Domain] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Statement Statement [Line Items] Ownership [Axis] Ownership [Axis] Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Total operating expenses Costs and Expenses Exchanges receivable Exchanges receivable Consists of natural gas and natural gas liquid delivery and receipt imbalances with others. For the midstream and intrastate segments, these amounts turn over monthly and are valued at market prices, which management believes approximates cost. For the interstate segment, natural gas imbalances, in-kind receivables and payables are recorded at the dollar weighted composite average of all current month gas transactions and dollar valued imbalances are recorded at contractual prices. Current assets: Assets, Current [Abstract] Natural Gas, US Regulated [Member] Natural Gas, US Regulated [Member] Debt Instrument, Fair Value Disclosure Debt Instrument, Fair Value Disclosure Regulatory Matters, Commitments, Contingencies And Environmental Liabilities [Abstract] Regulatory Matters, Commitments, Contingencies And Environmental Liabilities [Abstract] REGULATORY MATTERS, COMMITMENTS, CONTINGENCIES, AND ENVIRONMENTAL LIABILITIES [Abstract] Accounts receivable from related companies Accounts Receivable, Related Parties, Current Entity Address, Postal Zip Code Entity Address, Postal Zip Code Commitments and Contingencies Disclosure Commitments and Contingencies Disclosure [Text Block] Accounting Standards Update [Domain] Accounting Standards Update [Domain] Operating revenues Revenue from Related Parties Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Accounts Payable, Related Parties, Current Accounts Payable, Related Parties, Current Estimated litigation liability Estimated Litigation Liability Related Party [Axis] Related Party [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Related Party Related Party [Domain] Non-cash activity - Accrued capital expenditures Capital Expenditures Incurred but Not yet Paid Use of Estimates, Policy [Policy Text Block] Use of Estimates, Policy [Policy Text Block] Ownership Interest [Table] Ownership Interest [Table] Ownership Interest [Table] Document Quarterly Report Document Quarterly Report Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] OTHER INCOME (EXPENSE): Nonoperating Income (Expense) [Abstract] Exchanges payable Exchanges payable Consists of natural gas and natural gas liquid delivery and receipt imbalances with others. For the midstream and intrastate segments, these amounts turn over monthly and are value at market prices, which management believes approximates cost. For the interstate segment, natural gas imbalances, in-kind receivables and payables are recorded at the dollar weighted composite average of all current month gas transactions and dollar valued imbalances are recorded at contractual prices. Total assets Assets Entity Address, Address Line One Entity Address, Address Line One Net cash flows used in investing activities Net Cash Provided by (Used in) Investing Activities Entity Address, Address Line Two Entity Address, Address Line Two Interest expense — related company Interest Expense, Related Party Interest Expense, Related Party Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment OPERATING INCOME Operating Income (Loss) Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Entity Shell Company Entity Shell Company Document Type Document Type Product and Service [Domain] Product and Service [Domain] Liabilities, Current, Total Liabilities, Current Document Fiscal Year Focus Document Fiscal Year Focus Limited partner Limited Partner [Member] Operating and maintenance Operating Costs and Expenses Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Transportation and storage of natural gas Revenue from Contract with Customer, Including Assessed Tax Ownership [Domain] Ownership [Domain] Current Fiscal Year End Date Current Fiscal Year End Date Income Statement Income Statement [Line Items] Net Cash Provided by (Used in) Operating Activities Net Cash Provided by (Used in) Operating Activities Net Cash Provided by (Used in) Operating Activities Other Noncash Income (Expense) Other non-cash Other Noncash Income (Expense) Other, net Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Other current assets Other Assets, Current Partners' Capital [Abstract] Partners' Capital [Abstract] ETO [Member] ETO [Member] ETO [Member] Payments to Acquire Property, Plant, and Equipment Capital expenditures Payments to Acquire Property, Plant, and Equipment Other Liabilities, Current Other Liabilities, Current Notes Payable, Related Parties, Noncurrent Notes Payable, Related Parties, Noncurrent Contingent Residual Support Agreement, Amount Contingent Residual Support Agreement, Amount Amount of senior notes of an affiliate, the Partnership has agreed to provide contingent residual support for. COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Attributable to Parent Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document and Entity Information [Abstract] INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Net cash flows used in financing activities Net Cash Provided by (Used in) Financing Activities OTHER COMPREHENSIVE INCOME, NET OF TAX: Other Comprehensive Income (Loss), Net of Tax [Abstract] General partnership interest Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Entity Small Business Entity Small Business Partners' Capital, Total Partners' Capital Related Party Transaction [Line Items] Related Party Transaction [Line Items] City Area Code City Area Code ARO Assets [Axis] ARO Assets [Axis] ARO Assets [Axis] Operational Gas Sales Operational Gas Sales [Member] Operational Gas Sales Operations and Organization Nature of Operations [Text Block] Reconciliation of net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Scenario [Domain] Scenario [Domain] Liabilities and Equity, Total Liabilities and Equity Limited partnership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Statement, Partner Capital Components [Axis] Partner Capital Components [Axis] Fair Value Disclosures [Text Block] Fair Value Disclosures [Text Block] Entity Address, City or Town Entity Address, City or Town Scenario [Axis] Scenario [Axis] INCOME BEFORE INCOME TAX EXPENSE Income (Loss) Attributable to Parent, before Tax Related Party Transactions Related Party Transactions Disclosure [Text Block] Partners' Capital Limited Partners' Capital Account Liabilities and Equity [Abstract] Liabilities and Equity [Abstract]