0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 0000002 - Document - Audit Information link:presentationLink link:calculationLink link:definitionLink 9952151 - Statement - CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952153 - Statement - CONSOLIDATED STATEMENTS OF INCOME link:presentationLink link:calculationLink link:definitionLink 9952154 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:calculationLink link:definitionLink 9952156 - Statement - CONSOLIDATED STATEMENTS OF EQUITY link:presentationLink link:calculationLink link:definitionLink 9952157 - Statement - CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952158 - Statement - CONSOLIDATED BALANCE SHEETS - Southwest link:presentationLink link:calculationLink link:definitionLink 9952159 - Statement - CONSOLIDATED STATEMENTS OF INCOME - Southwest link:presentationLink link:calculationLink link:definitionLink 9952160 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - Southwest link:presentationLink link:calculationLink link:definitionLink 9952161 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS - Southwest link:presentationLink link:calculationLink link:definitionLink 9952162 - Statement - CONSOLIDATED STATEMENTS OF EQUITY - Southwest link:presentationLink link:calculationLink link:definitionLink 9952163 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 9952164 - Disclosure - Regulated Operations Plant and Leases link:presentationLink link:calculationLink link:definitionLink 9952165 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 9952166 - Disclosure - Receivables and Related Allowances link:presentationLink link:calculationLink link:definitionLink 9952167 - Disclosure - Regulatory Assets and Liabilities link:presentationLink link:calculationLink link:definitionLink 9952168 - Disclosure - Other Comprehensive Income and AOCI link:presentationLink link:calculationLink link:definitionLink 9952169 - Disclosure - Common Stock link:presentationLink link:calculationLink link:definitionLink 9952170 - Disclosure - Debt link:presentationLink link:calculationLink link:definitionLink 9952171 - Disclosure - Share-Based Compensation link:presentationLink link:calculationLink link:definitionLink 9952172 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 9952173 - Disclosure - Pension and Other Postretirement Benefits link:presentationLink link:calculationLink link:definitionLink 9952174 - Disclosure - Income Taxes link:presentationLink link:calculationLink link:definitionLink 9952175 - Disclosure - Segment Information link:presentationLink link:calculationLink link:definitionLink 9952176 - Disclosure - Redeemable Noncontrolling Interests link:presentationLink link:calculationLink link:definitionLink 9952177 - Disclosure - Dispositions link:presentationLink link:calculationLink link:definitionLink 9955511 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 9955512 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies (Tables) link:presentationLink link:calculationLink link:definitionLink 9955513 - Disclosure - Regulated Operations Plant and Leases (Tables) link:presentationLink link:calculationLink link:definitionLink 9955514 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 9955515 - Disclosure - Receivables and Related Allowances (Tables) link:presentationLink link:calculationLink link:definitionLink 9955516 - Disclosure - Regulatory Assets and Liabilities (Tables) link:presentationLink link:calculationLink link:definitionLink 9955517 - Disclosure - Other Comprehensive Income and AOCI (Tables) link:presentationLink link:calculationLink link:definitionLink 9955518 - Disclosure - Debt (Tables) link:presentationLink link:calculationLink link:definitionLink 9955519 - Disclosure - Share-Based Compensation (Tables) link:presentationLink link:calculationLink link:definitionLink 9955520 - Disclosure - Pension and Other Postretirement Benefits (Tables) link:presentationLink link:calculationLink link:definitionLink 9955521 - Disclosure - Income Taxes (Tables) link:presentationLink link:calculationLink link:definitionLink 9955522 - Disclosure - Segment Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9955523 - Disclosure - Redeemable Noncontrolling Interests (Tables) link:presentationLink link:calculationLink link:definitionLink 9955524 - Disclosure - Dispositions (Tables) link:presentationLink link:calculationLink link:definitionLink 9955525 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955526 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Schedule of Other Property and Investments (Details) link:presentationLink link:calculationLink link:definitionLink 9955527 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Summary of Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955528 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Schedule of Estimated Future Amortization of Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955529 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Schedule of Goodwill (Details) link:presentationLink link:calculationLink link:definitionLink 9955530 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Schedule of Capitalized and Debt Portion of AFUDC (Details) link:presentationLink link:calculationLink link:definitionLink 9955531 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Other Income (Deductions) (Details) link:presentationLink link:calculationLink link:definitionLink 9955532 - Disclosure - Background, Organization, and Summary of Significant Accounting Policies - Schedule of Earnings Per Share, Basic and Diluted (Details) link:presentationLink link:calculationLink link:definitionLink 9955533 - Disclosure - Regulated Operations Plant and Leases - Schedule of Regulated Operations Plant (Details) link:presentationLink link:calculationLink link:definitionLink 9955534 - Disclosure - Regulated Operations Plant and Leases - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955535 - Disclosure - Regulated Operations Plant and Leases - Schedule of Depreciation and Amortization Expense (Details) link:presentationLink link:calculationLink link:definitionLink 9955536 - Disclosure - Regulated Operations Plant and Leases - Components of Lease Expense (Details) link:presentationLink link:calculationLink link:definitionLink 9955537 - Disclosure - Regulated Operations Plant and Leases - Supplemental Cash Flow Information Related to Leases (Details) link:presentationLink link:calculationLink link:definitionLink 9955538 - Disclosure - Regulated Operations Plant and Leases - Supplemental Information Related to Leases Included in Balance Sheet (Details) link:presentationLink link:calculationLink link:definitionLink 9955539 - Disclosure - Regulated Operations Plant and Leases - Schedule of Maturities of Lease Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955539 - Disclosure - Regulated Operations Plant and Leases - Schedule of Maturities of Lease Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955540 - Disclosure - Revenue - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955540 - Disclosure - Revenue - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955541 - Disclosure - Revenue - Schedule of Regulated Operations Revenues: Natural Gas Distribution Segment (Details) link:presentationLink link:calculationLink link:definitionLink 9955542 - Disclosure - Revenue - Schedule of Regulated Operations Revenues: Utility Infrastructure Services Segment (Details) link:presentationLink link:calculationLink link:definitionLink 9955543 - Disclosure - Revenue - Summary of Information about Receivables (Details) link:presentationLink link:calculationLink link:definitionLink 9955544 - Disclosure - Revenue - Schedule of Utility Infrastructure Services Contracts Receivable (Details) link:presentationLink link:calculationLink link:definitionLink 9955545 - Disclosure - Receivables and Related Allowances - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955546 - Disclosure - Receivables and Related Allowances - Schedule of Accounts Receivable (Details) link:presentationLink link:calculationLink link:definitionLink 9955547 - Disclosure - Receivables and Related Allowances - Schedule of Percent of Customers by State (Details) link:presentationLink link:calculationLink link:definitionLink 9955548 - Disclosure - Receivables and Related Allowances - Schedule of Allowance for Uncollectibles (Details) link:presentationLink link:calculationLink link:definitionLink 9955549 - Disclosure - Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955550 - Disclosure - Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955551 - Disclosure - Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955552 - Disclosure - Other Comprehensive Income and AOCI - Related Tax Effects Allocated to OCI (Details) link:presentationLink link:calculationLink link:definitionLink 9955553 - Disclosure - Other Comprehensive Income and AOCI - AOCI Rollforward (Details) link:presentationLink link:calculationLink link:definitionLink 9955554 - Disclosure - Other Comprehensive Income and AOCI - Amount Recognized Before Income Tax Associated with Defined Benefit Plans in Accumulated Other Comprehensive Income (Details) link:presentationLink link:calculationLink link:definitionLink 9955555 - Disclosure - Common Stock (Details) link:presentationLink link:calculationLink link:definitionLink 9955556 - Disclosure - Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9955556 - Disclosure - Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9955557 - Disclosure - Debt - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955558 - Disclosure - Debt - Summary of Effective Interest Rates on Variable-Rate IDRBs (Details) link:presentationLink link:calculationLink link:definitionLink 9955559 - Disclosure - Debt - Estimated Maturities of Long-Term Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9955560 - Disclosure - Share-Based Compensation - Schedule of Share-Based Plan Compensation Expense, Including Cash Award (Details) link:presentationLink link:calculationLink link:definitionLink 9955561 - Disclosure - Share-Based Compensation - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955562 - Disclosure - Share-Based Compensation - Schedule of Nonvested Performance and Restricted Stock Unit Plans (Details) link:presentationLink link:calculationLink link:definitionLink 9955563 - Disclosure - Commitments and Contingencies (Details) link:presentationLink link:calculationLink link:definitionLink 9955564 - Disclosure - Pension and Other Postretirement Benefits - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955565 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Assumptions Used (Details) link:presentationLink link:calculationLink link:definitionLink 9955566 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in Balance Sheet and Income Statement (Details) link:presentationLink link:calculationLink link:definitionLink 9955567 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Accumulated Benefit Obligation (Details) link:presentationLink link:calculationLink link:definitionLink 9955568 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Expected Benefit Payments (Details) link:presentationLink link:calculationLink link:definitionLink 9955569 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Net Periodic Benefit Cost and Weighted-Average Assumptions (Details) link:presentationLink link:calculationLink link:definitionLink 9955570 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Details) link:presentationLink link:calculationLink link:definitionLink 9955571 - Disclosure - Pension and Other Postretirement Benefits - Schedule of Fair Value of Plan Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955572 - Disclosure - Income Taxes - Summary of Income Before Taxes and Noncontrolling Interest for Domestic and Foreign Operations (Details) link:presentationLink link:calculationLink link:definitionLink 9955573 - Disclosure - Income Taxes - Summary of Income Tax Expense (Benefit) (Details) link:presentationLink link:calculationLink link:definitionLink 9955574 - Disclosure - Income Taxes - Significant Components of Deferred Income Tax Expense (Benefit) (Details) link:presentationLink link:calculationLink link:definitionLink 9955575 - Disclosure - Income Taxes - Reconciliation of U.S Federal Statutory Rate to Consolidated Effective Tax Rate (Details) link:presentationLink link:calculationLink link:definitionLink 9955576 - Disclosure - Income Taxes - Deferred Tax Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955577 - Disclosure - Income Taxes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955578 - Disclosure - Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) link:presentationLink link:calculationLink link:definitionLink 9955579 - Disclosure - Income Taxes - Summary of Income Before Taxes for Continuing and Discontinued Operations (Details) link:presentationLink link:calculationLink link:definitionLink 9955580 - Disclosure - Segment Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955581 - Disclosure - Segment Information - Accounts Receivable for Services (Details) link:presentationLink link:calculationLink link:definitionLink 9955582 - Disclosure - Segment Information - Schedule of Revenues by Geographic Area (Details) link:presentationLink link:calculationLink link:definitionLink 9955583 - Disclosure - Segment Information - Schedule of Segment Reporting Information (Details) link:presentationLink link:calculationLink link:definitionLink 9955584 - Disclosure - Redeemable Noncontrolling Interests - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955585 - Disclosure - Redeemable Noncontrolling Interests - Summary of Redeemable Noncontrolling Interest (Details) link:presentationLink link:calculationLink link:definitionLink 9955586 - Disclosure - Dispositions - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955587 - Disclosure - Dispositions - Schedule of Ownership Interests (Details) link:presentationLink link:calculationLink link:definitionLink