Business and Basis of Presentation	6 Months Ended
Jun. 30, 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. In June 2016, Talen Energy Corporation announced the Merger with affiliates of Riverstone Holdings LLC, a private investment firm, in which all outstanding shares of common stock not owned by Riverstone affiliated entities will be acquired, subject to certain exceptions. The transaction is expected to be completed by the end of 2016, subject to regulatory and stockholder approval and satisfaction of other closing conditions. See Note 7 for additional information. Spinoff from PPL Following the June 2015 spinoff from PPL, 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 and six months ended June 30, 2016, the costs incurred for these services were $10 million and $22 million. The costs incurred for these services during the three and six months ended June 30, 2015 were not significant. In connection with the spinoff transaction in 2015, additional employee-related costs were incurred by Talen Energy, which primarily related to accelerated stock-based compensation and pro-rated performance-based cash incentive and stock-based compensation awards previously issued under PPL stock incentive programs, primarily for Talen Energy Supply employees and for PPL employees who became Talen Energy Supply employees in connection with the transaction. These costs were recognized at the closing of the spinoff. During the three and six months ended June 30, 2015, Talen Energy Supply recorded $25 million related to these accelerated stock-based compensation and pro-rated stock-based compensation awards. The vesting for all Talen Energy Supply employees was accelerated and all remaining unrecognized compensation expense was accelerated concurrently with the spinoff. See Note 8 in Talen Energy's 2015 Form 10-K for additional information on stock-based compensation. In addition, during the three and six months ended June 30, 2015, Talen Energy incurred $8 million and $10 million of restructuring costs related to the spinoff transaction which are recorded in "Operation and maintenance" on the Statements of Income. 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 and six months ended June 30, 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. From June 1, 2015, upon completion of the spinoff and acquisition, Talen Energy Corporation's and Talen Energy Supply's consolidated financial information also includes RJS. As such, Talen Energy Corporation's and Talen Energy Supply's consolidated financial information presented in this Quarterly Report on Form 10-Q for the 2015 periods represents three and six months of legacy Talen Energy Supply information consolidated with one month of RJS information from June 1, 2015. Talen Energy completed the acquisition of MACH Gen in November 2015. MACH Gen's operating results for the three and six months ended June 30, 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. See Note 8 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 June 30, 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 to previously reported 2015 amounts, there were equal and offsetting changes between "Operating Revenues" and "Operating Expenses" with no impact on "Operating Income (Loss)" on the 2015 Statement of Income. This change in presentation resulted in a decrease of $125 million for the three months ended June 30, 2015 and an increase of $20 million for the six months ended June 30, 2015 in "Wholesale energy" and "Fuel and energy purchases" on the Statement of Income. Also, presentation on the 2015 Statement of Income was modified to combine "Fuel" and "Energy purchases" in a single line item and to reclassify certain "Operating Expenses" to align the presentation of these operating expenses with how Talen Energy management views these costs. This change in presentation for certain operating expenses resulted in an increase of $15 million and $33 million for the three and six months ended June 30, 2015 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 and six months ended June 30, 2015. In addition, the operating results of the Sapphire portfolio for the three and six months ended June 30, 2015 were reclassified to continuing operations as a result of the November 2015 FERC order approving the third mitigation package relating to the transactions that formed Talen Energy. This change in presentation resulted in an increase for the three and six months ended June 30, 2015 of $8 million to "Operating Revenues" and $7 million to "Operating Expenses." This change had an insignificant increase to "Operating Income (Loss)" for the three and six months ended June 30, 2015. See Note 1 in Talen Energy's 2015 Form 10-K for additional information on the initial classification as discontinued operations and the November 2015 FERC Order. During the three and six months ended June 30, 2015, Talen Energy recorded a $7 million decrease to "Retail energy" revenues on the Statements of Income. Prior to this date, Talen Energy billed and collected amounts from a third party that had a transmission operating agreement with Talen Energy's former affiliate, PPL Electric Utilities Corporation. Such amounts should have been recognized as an affiliate payable, but were inadvertently recorded as revenue. The $4 million after-tax ($0.04 per share for Talen Energy Corporation) impact of correcting this overstatement of "Retail energy" revenues decreased "Net Income (Loss)" during the three and six months ended June 30, 2015. The impact of the overstatement was not material to the previously-issued financial statements and the correction was not material to the full year results for 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.

In June 2016, Talen Energy Corporation announced the Merger with affiliates of Riverstone Holdings LLC, a private investment firm, in which all outstanding shares of common stock not owned by Riverstone affiliated entities will be acquired, subject to certain exceptions. The transaction is expected to be completed by the end of 2016, subject to regulatory and stockholder approval and satisfaction of other closing conditions. See Note 7 for additional information.

Spinoff from PPL

Following the June 2015 spinoff from PPL, 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 and six months ended June 30, 2016, the costs incurred for these services were $10 million and $22 million. The costs incurred for these services during the three and six months ended June 30, 2015 were not significant.

In connection with the spinoff transaction in 2015, additional employee-related costs were incurred by Talen Energy, which primarily related to accelerated stock-based compensation and pro-rated performance-based cash incentive and stock-based compensation awards previously issued under PPL stock incentive programs, primarily for Talen Energy Supply employees and for PPL employees who became Talen Energy Supply employees in connection with the transaction. These costs were recognized at the closing of the spinoff. During the three and six months ended June 30, 2015, Talen Energy Supply recorded $25 million related to these accelerated stock-based compensation and pro-rated stock-based compensation awards. The vesting for all Talen Energy Supply employees was accelerated and all remaining unrecognized compensation expense was accelerated concurrently with the spinoff. See Note 8 in Talen Energy's 2015 Form 10-K for additional information on stock-based compensation.

In addition, during the three and six months ended June 30, 2015, Talen Energy incurred $8 million and $10 million of restructuring costs related to the spinoff transaction which are recorded in "Operation and maintenance" on the Statements of Income.

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 and six months ended June 30, 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. From June 1, 2015, upon completion of the spinoff and acquisition, Talen Energy Corporation's and Talen Energy Supply's consolidated financial information also includes RJS. As such, Talen Energy Corporation's and Talen Energy Supply's consolidated financial information presented in this Quarterly Report on Form 10-Q for the 2015 periods represents three and six months of legacy Talen Energy Supply information consolidated with one month of RJS information from June 1, 2015.

Talen Energy completed the acquisition of MACH Gen in November 2015. MACH Gen's operating results for the three and six months ended June 30, 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. See Note 8 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 June 30, 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 to previously reported 2015 amounts, there were equal and offsetting changes between "Operating Revenues" and "Operating Expenses" with no impact on "Operating Income (Loss)" on the 2015 Statement of Income. This change in presentation resulted in a decrease of $125 million for the three months ended June 30, 2015 and an increase of $20 million for the six months ended June 30, 2015 in "Wholesale energy" and "Fuel and energy purchases" on the Statement of Income.

Also, presentation on the 2015 Statement of Income was modified to combine "Fuel" and "Energy purchases" in a single line item and to reclassify certain "Operating Expenses" to align the presentation of these operating expenses with how Talen Energy management views these costs. This change in presentation for certain operating expenses resulted in an increase of $15 million and $33 million for the three and six months ended June 30, 2015 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 and six months ended June 30, 2015.

In addition, the operating results of the Sapphire portfolio for the three and six months ended June 30, 2015 were reclassified to continuing operations as a result of the November 2015 FERC order approving the third mitigation package relating to the transactions that formed Talen Energy. This change in presentation resulted in an increase for the three and six months ended June 30, 2015 of $8 million to "Operating Revenues" and $7 million to "Operating Expenses." This change had an insignificant increase to "Operating Income (Loss)" for the three and six months ended June 30, 2015. See Note 1 in Talen Energy's 2015 Form 10-K for additional information on the initial classification as discontinued operations and the November 2015 FERC Order.

During the three and six months ended June 30, 2015, Talen Energy recorded a $7 million decrease to "Retail energy" revenues on the Statements of Income. Prior to this date, Talen Energy billed and collected amounts from a third party that had a transmission operating agreement with Talen Energy's former affiliate, PPL Electric Utilities Corporation. Such amounts should have been recognized as an affiliate payable, but were inadvertently recorded as revenue. The $4 million after-tax ($0.04 per share for Talen Energy Corporation) impact of correcting this overstatement of "Retail energy" revenues decreased "Net Income (Loss)" during the three and six months ended June 30, 2015. The impact of the overstatement was not material to the previously-issued financial statements and the correction was not material to the full year results for 2015.