New Financial Accounting Standards	9 Months Ended
New Financial Accounting Standards	Sep. 30, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Financial Accounting Standards	New Financial Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board (IASB) jointly issued a revenue recognition standard that will supersede the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance under the Codification through Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The purpose of the new guidance is to create a consistent framework for revenue recognition. The guidance clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. In August 2015, the FASB issued amendments to defer the effective date of ASU No. 2014-09 to reporting periods beginning after December 15, 2017 through ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date”. Early adoption is permitted for reporting periods beginning after December 15, 2016. The Companies are in the process of evaluating the application and impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In January 2015, the FASB issued amendments on income statement guidance through ASU No. 2015-01, “Income Statement—Extraordinary and Unusual Items (Subtopic 225-20).” The amendments eliminate from GAAP the concept of extraordinary items. The amendments are effective for reporting periods beginning after December 15, 2015. Early adoption is permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In February 2015, the FASB issued amendments on consolidation guidance through ASU No. 2015-02, “Consolidation (Topic 810).” The amendments provide additional guidance for VIE accounting of limited partnerships and similar legal entities, fees paid to decision makers of a VIE, the effect of fee arrangements on primary beneficiary determination, and the effect of related parties on primary beneficiary determination. The amendments are effective prospectively for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In April 2015, the FASB issued amendments on debt issuance costs guidance through ASU No. 2015-03, “Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs.” The amendments provide additional guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a reduction of that debt liability rather than as a deferred cost (i.e. an asset) as required by current guidance. The FASB further clarified debt issuance cost guidance in August 2015 through ASU 2015-15, “Presentation and Subsequent Measurement of Debt Issuance Costs Associated With Line-of-Credit Arrangements,” which allows entities to continue presenting debt issuance costs related to line-of-credit arrangements as deferred costs on the balance sheet. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In April 2015, the FASB issued amendments on internal-use software guidance through ASU No. 2015-05, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement.” The amendments provide guidance to customers about whether a cloud computing arrangement should be accounted for as a license of internal use software or as a service contract. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2015, the FASB issued amendments on disclosure guidance for investments using Net Asset Value per Share through ASU No. 2015-07, “Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent).” The amendments remove the requirement to categorize investments in the fair value hierarchy if Net Asset Value per Share is used as a practical expedient to determine the fair value of the investment. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In July 2015, the FASB issued amendments on the measurement of first-in, first-out and average cost inventory through ASU No.2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory.” The amendments require that inventory within the scope of the guidance be measured at the lower of cost and net realizable value rather than cost and market value. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2016. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2015, the FASB issued amendments on the accounting for derivative contracts through ASU No.2015-13, “Derivatives and Hedging (Topic 815): Application of the Normal Purchases and Normal Sales Scope Exception to Certain Electricity Contracts within Nodal Energy Markets.” The amendments specify that the use of locational marginal pricing by an independent system operator does not constitute a net settlement of a contract and would not cause the contract to fail the physical delivery criterion of the normal purchases and normal sales scope exception. The amendments are effective upon issuance and should be applied prospectively. The application of this guidance does not have a material impact on the Companies' financial position, results of operations and liquidity. In September 2015, the FASB issued an amendment to guidance for business combinations through ASU No. 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments.” The amendment requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined as opposed to recognizing retrospectively. The amendment also requires that the acquirer record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. For public entities, the amendment is effective prospectively for reporting periods beginning after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity.
CECONY
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Financial Accounting Standards	New Financial Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board (IASB) jointly issued a revenue recognition standard that will supersede the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance under the Codification through Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The purpose of the new guidance is to create a consistent framework for revenue recognition. The guidance clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. In August 2015, the FASB issued amendments to defer the effective date of ASU No. 2014-09 to reporting periods beginning after December 15, 2017 through ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date”. Early adoption is permitted for reporting periods beginning after December 15, 2016. The Companies are in the process of evaluating the application and impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In January 2015, the FASB issued amendments on income statement guidance through ASU No. 2015-01, “Income Statement—Extraordinary and Unusual Items (Subtopic 225-20).” The amendments eliminate from GAAP the concept of extraordinary items. The amendments are effective for reporting periods beginning after December 15, 2015. Early adoption is permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In February 2015, the FASB issued amendments on consolidation guidance through ASU No. 2015-02, “Consolidation (Topic 810).” The amendments provide additional guidance for VIE accounting of limited partnerships and similar legal entities, fees paid to decision makers of a VIE, the effect of fee arrangements on primary beneficiary determination, and the effect of related parties on primary beneficiary determination. The amendments are effective prospectively for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In April 2015, the FASB issued amendments on debt issuance costs guidance through ASU No. 2015-03, “Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs.” The amendments provide additional guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a reduction of that debt liability rather than as a deferred cost (i.e. an asset) as required by current guidance. The FASB further clarified debt issuance cost guidance in August 2015 through ASU 2015-15, “Presentation and Subsequent Measurement of Debt Issuance Costs Associated With Line-of-Credit Arrangements,” which allows entities to continue presenting debt issuance costs related to line-of-credit arrangements as deferred costs on the balance sheet. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In April 2015, the FASB issued amendments on internal-use software guidance through ASU No. 2015-05, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement.” The amendments provide guidance to customers about whether a cloud computing arrangement should be accounted for as a license of internal use software or as a service contract. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2015, the FASB issued amendments on disclosure guidance for investments using Net Asset Value per Share through ASU No. 2015-07, “Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent).” The amendments remove the requirement to categorize investments in the fair value hierarchy if Net Asset Value per Share is used as a practical expedient to determine the fair value of the investment. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In July 2015, the FASB issued amendments on the measurement of first-in, first-out and average cost inventory through ASU No.2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory.” The amendments require that inventory within the scope of the guidance be measured at the lower of cost and net realizable value rather than cost and market value. For public entities, the amendments are effective for reporting periods beginning on or after December 15, 2016. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2015, the FASB issued amendments on the accounting for derivative contracts through ASU No.2015-13, “Derivatives and Hedging (Topic 815): Application of the Normal Purchases and Normal Sales Scope Exception to Certain Electricity Contracts within Nodal Energy Markets.” The amendments specify that the use of locational marginal pricing by an independent system operator does not constitute a net settlement of a contract and would not cause the contract to fail the physical delivery criterion of the normal purchases and normal sales scope exception. The amendments are effective upon issuance and should be applied prospectively. The application of this guidance does not have a material impact on the Companies' financial position, results of operations and liquidity. In September 2015, the FASB issued an amendment to guidance for business combinations through ASU No. 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments.” The amendment requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined as opposed to recognizing retrospectively. The amendment also requires that the acquirer record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. For public entities, the amendment is effective prospectively for reporting periods beginning after December 15, 2015. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity.