Business and Basis of Presentation	3 Months Ended
Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Capitalized terms and abbreviations appearing in the unaudited combined notes to condensed consolidated financial statements are defined in the glossary. Dollars are in millions, except per share data, unless otherwise noted. As Talen Energy Corporation is substantially comprised of Talen Energy Supply, LLC and its subsidiaries, to avoid repetition, most disclosures refer to Talen Energy which indicates the disclosure applies to Talen Energy Corporation and Talen Energy Supply, LLC. This presentation has been applied where identification of particular subsidiaries is not material to the matter being disclosed, and to conform narrative disclosures to the presentation of financial information on a consolidated basis. When identification of a particular registrant or subsidiary is considered important to understanding the matter being disclosed, the specific entity's name is used, in particular, for those few disclosures that apply only to Talen Energy Corporation. Each disclosure referring to a subsidiary applies to both Talen Energy Corporation and Talen Energy Supply and each disclosure referring to Talen Energy Supply applies to Talen Energy Corporation through consolidation. Business Talen Energy Corporation, through its principal subsidiary Talen Energy Supply, is a North American competitive power generation and marketing company primarily engaged in the production and sale of electricity, capacity and ancillary products. Talen Energy is headquartered in Allentown, Pennsylvania and owns and operates a portfolio of generation assets principally located in the Northeast, Mid-Atlantic and Southwest regions of the U.S. See "Item 1. Business" in Talen Energy's 2015 Form 10-K for a discussion of Talen Energy's business, including the June 2015 spinoff from PPL and formation of Talen Energy Corporation. Following the June 2015 spinoff, certain services, including information technology, financial and accounting, human resource and other specified services are provided by PPL on a transition basis pursuant to the TSA. The TSA with PPL is for a period of up to two years from the date of the spinoff. For the three months ended March 31, 2016, the costs incurred for these services were $12 million. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X and, therefore, do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation in accordance with GAAP are reflected in the condensed consolidated financial statements. All adjustments are of a normal recurring nature, except as otherwise disclosed. The Balance Sheets at December 31, 2015 are derived from Talen Energy's 2015 audited Balance Sheet. The financial statements and notes thereto should be read in conjunction with the financial statements and notes contained in Talen Energy's 2015 Form 10-K. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the results to be expected for the full year ending December 31, 2016 or other future periods, because results for interim periods can be disproportionately influenced by various factors, developments and seasonal variations. Talen Energy Supply is considered the accounting predecessor of Talen Energy Corporation. Therefore, the financial information prior to the June 2015 spinoff presented in this Quarterly Report on Form 10-Q for both registrants includes only legacy Talen Energy Supply information. Talen Energy completed the acquisition of RJS Power in June 2015 and the acquisition of MACH Gen in November 2015. See Note 6 in Talen Energy's 2015 Form 10-K for additional information. RJS and MACH Gen's operating results for the three months ended March 31, 2016 are included in Talen Energy's results of operations with no comparable amounts for the same period in 2015. The assets and liabilities related to the Holtwood, Lake Wallenpaupack, C.P. Crane and Ironwood facilities were classified as "Assets held for sale" and "Liabilities held for sale" at December 31, 2015, while Holtwood and Lake Wallenpaupack remain classified as such at March 31, 2016. See Note 7 for additional information on these divestitures. The sales of Talen Ironwood Holdings, LLC and C.P. Crane LLC were completed in February 2016 and the sale of the Holtwood and Lake Wallenpaupack hydroelectric facilities was completed in April 2016. The sales satisfied the requirement to divest certain PJM assets to comply with a December 2014 FERC order approving the combination with RJS Power. The classification of certain prior period amounts has been changed to conform to the presentation in the March 31, 2016 financial statements as discussed below. In these financial statements, revenue and expense from derivatives is recorded based on Talen Energy's economic hedging strategy. For example, all purchases and sales associated with economic hedging of the sale of energy using contracts accounted for as derivatives are recorded within "Operating Revenues" and all purchases and sales associated with economic hedging of the procurement of fuel or purchasing energy using contracts accounted for as derivatives are recorded as "Operating Expenses" on the Statements of Income. Prior to the fourth quarter of 2015, Talen Energy classified all non-trading commodity hedge transactions as revenue or expense based upon whether each specific transaction was a sale or purchase, which in certain instances, created losses within revenue and gains within expense. As a result of this change in presentation, there was an equal and offsetting increase of $145 million for the three months ended March 31, 2015 in "Wholesale energy" and "Fuel and energy purchases" on the Statement of Income. In addition, to align the presentation of certain operating expenses with how Talen Energy management views these costs, reclassifications were made within "Operating Expenses" on the 2015 Statement of Income. This change in presentation resulted in an increase of $18 million to "Fuel and energy purchases" with offsetting decreases, primarily to "Taxes, other than income," but also to "Operation and maintenance" and "Energy-related businesses." This change had no impact on "Operating Income (Loss)" for the three months ended March 31, 2015.

Business and Basis of Presentation

Capitalized terms and abbreviations appearing in the unaudited combined notes to condensed consolidated financial statements are defined in the glossary. Dollars are in millions, except per share data, unless otherwise noted. As Talen Energy Corporation is substantially comprised of Talen Energy Supply, LLC and its subsidiaries, to avoid repetition, most disclosures refer to Talen Energy which indicates the disclosure applies to Talen Energy Corporation and Talen Energy Supply, LLC. This presentation has been applied where identification of particular subsidiaries is not material to the matter being disclosed, and to conform narrative disclosures to the presentation of financial information on a consolidated basis. When identification of a particular registrant or subsidiary is considered important to understanding the matter being disclosed, the specific entity's name is used, in particular, for those few disclosures that apply only to Talen Energy Corporation. Each disclosure referring to a subsidiary applies to both Talen Energy Corporation and Talen Energy Supply and each disclosure referring to Talen Energy Supply applies to Talen Energy Corporation through consolidation.

Business

Talen Energy Corporation, through its principal subsidiary Talen Energy Supply, is a North American competitive power generation and marketing company primarily engaged in the production and sale of electricity, capacity and ancillary products. Talen Energy is headquartered in Allentown, Pennsylvania and owns and operates a portfolio of generation assets principally located in the Northeast, Mid-Atlantic and Southwest regions of the U.S. See "Item 1. Business" in Talen Energy's 2015 Form 10-K for a discussion of Talen Energy's business, including the June 2015 spinoff from PPL and formation of Talen Energy Corporation.

Following the June 2015 spinoff, certain services, including information technology, financial and accounting, human resource and other specified services are provided by PPL on a transition basis pursuant to the TSA. The TSA with PPL is for a period of up to two years from the date of the spinoff. For the three months ended March 31, 2016, the costs incurred for these services were $12 million.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X and, therefore, do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation in accordance with GAAP are reflected in the condensed consolidated financial statements. All adjustments are of a normal recurring nature, except as otherwise disclosed. The Balance Sheets at December 31, 2015 are derived from Talen Energy's 2015 audited Balance Sheet. The financial statements and notes thereto should be read in conjunction with the financial statements and notes contained in Talen Energy's 2015 Form 10-K. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the results to be expected for the full year ending December 31, 2016 or other future periods, because results for interim periods can be disproportionately influenced by various factors, developments and seasonal variations.

Talen Energy Supply is considered the accounting predecessor of Talen Energy Corporation. Therefore, the financial information prior to the June 2015 spinoff presented in this Quarterly Report on Form 10-Q for both registrants includes only legacy Talen Energy Supply information.

Talen Energy completed the acquisition of RJS Power in June 2015 and the acquisition of MACH Gen in November 2015. See Note 6 in Talen Energy's 2015 Form 10-K for additional information. RJS and MACH Gen's operating results for the three months ended March 31, 2016 are included in Talen Energy's results of operations with no comparable amounts for the same period in 2015.

The assets and liabilities related to the Holtwood, Lake Wallenpaupack, C.P. Crane and Ironwood facilities were classified as "Assets held for sale" and "Liabilities held for sale" at December 31, 2015, while Holtwood and Lake Wallenpaupack remain classified as such at March 31, 2016. See Note 7 for additional information on these divestitures.

The sales of Talen Ironwood Holdings, LLC and C.P. Crane LLC were completed in February 2016 and the sale of the Holtwood and Lake Wallenpaupack hydroelectric facilities was completed in April 2016. The sales satisfied the requirement to divest certain PJM assets to comply with a December 2014 FERC order approving the combination with RJS Power.

The classification of certain prior period amounts has been changed to conform to the presentation in the March 31, 2016 financial statements as discussed below.

In these financial statements, revenue and expense from derivatives is recorded based on Talen Energy's economic hedging strategy. For example, all purchases and sales associated with economic hedging of the sale of energy using contracts accounted for as derivatives are recorded within "Operating Revenues" and all purchases and sales associated with economic hedging of the procurement of fuel or purchasing energy using contracts accounted for as derivatives are recorded as "Operating Expenses" on the Statements of Income. Prior to the fourth quarter of 2015, Talen Energy classified all non-trading commodity hedge transactions as revenue or expense based upon whether each specific transaction was a sale or purchase, which in certain instances, created losses within revenue and gains within expense. As a result of this change in presentation, there was an equal and offsetting increase of $145 million for the three months ended March 31, 2015 in "Wholesale energy" and "Fuel and energy purchases" on the Statement of Income.

In addition, to align the presentation of certain operating expenses with how Talen Energy management views these costs, reclassifications were made within "Operating Expenses" on the 2015 Statement of Income. This change in presentation resulted in an increase of $18 million to "Fuel and energy purchases" with offsetting decreases, primarily to "Taxes, other than income," but also to "Operation and maintenance" and "Energy-related businesses." This change had no impact on "Operating Income (Loss)" for the three months ended March 31, 2015.