0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 9952151 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) link:presentationLink link:calculationLink link:definitionLink 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) (Parentheticals) link:presentationLink link:calculationLink link:definitionLink 9952153 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) link:presentationLink link:calculationLink link:definitionLink 9952154 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) (Parentheticals) link:presentationLink link:calculationLink link:definitionLink 9952156 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (unaudited) link:presentationLink link:calculationLink link:definitionLink 9952157 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (unaudited) (Parentheticals) link:presentationLink link:calculationLink link:definitionLink 9952158 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) link:presentationLink link:calculationLink link:definitionLink 9952159 - Disclosure - Summary of Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 9952160 - Disclosure - Segment Information link:presentationLink link:calculationLink link:definitionLink 9952161 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 9952162 - Disclosure - Select Balance Sheet Information link:presentationLink link:calculationLink link:definitionLink 9952163 - Disclosure - Regulatory Matters link:presentationLink link:calculationLink link:definitionLink 9952164 - Disclosure - Asset Retirement Obligations link:presentationLink link:calculationLink link:definitionLink 9952165 - Disclosure - Short-Term and Long-Term Borrowings link:presentationLink link:calculationLink link:definitionLink 9952166 - Disclosure - Employee Postretirement Benefits link:presentationLink link:calculationLink link:definitionLink 9952167 - Disclosure - Income Taxes link:presentationLink link:calculationLink link:definitionLink 9952168 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 9952169 - Disclosure - Shareholders' Equity link:presentationLink link:calculationLink link:definitionLink 9952170 - Disclosure - Accumulated Other Comprehensive Income (Loss) link:presentationLink link:calculationLink link:definitionLink 9952171 - Disclosure - Share-Based Payments link:presentationLink link:calculationLink link:definitionLink 9952172 - Disclosure - Earnings Per Share link:presentationLink link:calculationLink link:definitionLink 9952173 - Disclosure - Derivative Instruments link:presentationLink link:calculationLink link:definitionLink 9952174 - Disclosure - Fair Value Measurements link:presentationLink link:calculationLink link:definitionLink 9955511 - Disclosure - Summary of Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 9955512 - Disclosure - Segment Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9955513 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 9955514 - Disclosure - Select Balance Sheet Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9955515 - Disclosure - Regulatory Matters (Tables) link:presentationLink link:calculationLink link:definitionLink 9955516 - Disclosure - Asset Retirement Obligations (Tables) link:presentationLink link:calculationLink link:definitionLink 9955517 - Disclosure - Short-Term and Long-Term Borrowings (Tables) link:presentationLink link:calculationLink link:definitionLink 9955518 - Disclosure - Employee Postretirement Benefits (Tables) link:presentationLink link:calculationLink link:definitionLink 9955519 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Tables) link:presentationLink link:calculationLink link:definitionLink 9955520 - Disclosure - Share-Based Payments (Tables) link:presentationLink link:calculationLink link:definitionLink 9955521 - Disclosure - Earnings Per Share (Tables) link:presentationLink link:calculationLink link:definitionLink 9955522 - Disclosure - Derivative Instruments (Tables) link:presentationLink link:calculationLink link:definitionLink 9955523 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 9955524 - Disclosure - Summary of Significant Accounting Policies (Details) link:presentationLink link:calculationLink link:definitionLink 9955525 - Disclosure - Segment Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955526 - Disclosure - Segment Information - Schedule of Segment Profit or Loss (Details) link:presentationLink link:calculationLink link:definitionLink 9955527 - Disclosure - Segment Information - Schedule of Capital Expenditures and Identifiable Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955528 - Disclosure - Segment Information - Schedule of Reconciliation to Consolidated Amounts (Details) link:presentationLink link:calculationLink link:definitionLink 9955529 - Disclosure - Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9955530 - Disclosure - Select Balance Sheet Information - Schedule of Restricted and Unrestricted Cash (Details) link:presentationLink link:calculationLink link:definitionLink 9955531 - Disclosure - Select Balance Sheet Information - Schedule of Receivables (Details) link:presentationLink link:calculationLink link:definitionLink 9955532 - Disclosure - Select Balance Sheet Information - Schedule of Activity in Allowance for Credit Losses (Details) link:presentationLink link:calculationLink link:definitionLink 9955533 - Disclosure - Select Balance Sheet Information - Schedule of Inventories (Details) link:presentationLink link:calculationLink link:definitionLink 9955534 - Disclosure - Select Balance Sheet Information - Schedule of Investments (Details) link:presentationLink link:calculationLink link:definitionLink 9955535 - Disclosure - Select Balance Sheet Information - Schedule of Amortized Costs and Fair Value of Debt Securities, Available-for-Sale (Details) link:presentationLink link:calculationLink link:definitionLink 9955536 - Disclosure - Select Balance Sheet Information - Schedule of Investments Classified by Contractual Maturity Date (Details) link:presentationLink link:calculationLink link:definitionLink 9955537 - Disclosure - Select Balance Sheet Information - Schedule of Property, Plant and Equipment (Details) link:presentationLink link:calculationLink link:definitionLink 9955538 - Disclosure - Select Balance Sheet Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955539 - Disclosure - Regulatory Matters - Schedule of Regulatory Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955540 - Disclosure - Regulatory Matters - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955541 - Disclosure - Asset Retirement Obligations - Schedule of Change in Asset Retirement Obligations (Details) link:presentationLink link:calculationLink link:definitionLink 9955542 - Disclosure - Asset Retirement Obligations - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955543 - Disclosure - Short-Term and Long-Term Borrowings - Lines of Credit (Details) link:presentationLink link:calculationLink link:definitionLink 9955544 - Disclosure - Short-Term and Long-Term Borrowings - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955545 - Disclosure - Short-Term and Long-Term Borrowings - Breakdown of Outstanding Long-term Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9955546 - Disclosure - Employee Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) link:presentationLink link:calculationLink link:definitionLink 9955547 - Disclosure - Employee Postretirement Benefits - Composition of Periodic Benefit Cost (Details) link:presentationLink link:calculationLink link:definitionLink 9955548 - Disclosure - Employee Postretirement Benefits - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955549 - Disclosure - Income Taxes (Details) link:presentationLink link:calculationLink link:definitionLink 9955550 - Disclosure - Commitments and Contingencies (Details) link:presentationLink link:calculationLink link:definitionLink 9955551 - Disclosure - Shareholders' Equity (Details) link:presentationLink link:calculationLink link:definitionLink 9955552 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Details) link:presentationLink link:calculationLink link:definitionLink 9955553 - Disclosure - Share-Based Payments - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955554 - Disclosure - Share-Based Payments - Summary of Restricted Stock Awards and Stock Performance Awards (Details) link:presentationLink link:calculationLink link:definitionLink 9955555 - Disclosure - Share-Based Payments - Weighted-Average Assumptions (Details) link:presentationLink link:calculationLink link:definitionLink 9955556 - Disclosure - Earnings Per Share (Details) link:presentationLink link:calculationLink link:definitionLink 9955557 - Disclosure - Derivative Instruments - Schedule of Notional Amounts and Fair Value (Details) link:presentationLink link:calculationLink link:definitionLink 9955558 - Disclosure - Derivative Instruments - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955559 - Disclosure - Fair Value Measurements - Schedule of Fair Value Measurements, Recurring and Nonrecurring (Details) link:presentationLink link:calculationLink link:definitionLink 9955560 - Disclosure - Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink