Illinois Power Generating 10-Q 10 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 10, 2016
Entity [Abstract]
Entity Registrant Name	ILLINOIS POWER GENERATING COMPANY
Entity Central Index Key	1,135,361
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		2,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Current Assets
Cash	$ 84	$ 61
Restricted cash	6	0
Accounts receivable, affiliates	63	54
Accounts receivable	7	8
Inventory	96	133
Prepayments and other current assets	7	6
Total Current Assets	263	262
Property, Plant and Equipment, Net	207	937
Other assets	27	27
Total Assets	497	1,226
Current Liabilities
Accounts payable	22	26
Accounts payable, affiliates	40	18
Taxes accrued	7	10
Accrued interest	25	10
Accrued liabilities and other current liabilities	8	9
Total Current Liabilities	102	73
Long-term debt	821	820
Deferred income taxes, net	1	119
Asset retirement obligations	50	49
Other long-term liabilities	25	24
Total Liabilities	999	1,085
Commitments and Contingencies (Note 9)
Stockholder’s Equity
Common stock, no par value, 10,000 shares authorized 2,000 shares outstanding	0	0
Additional paid-in capital	542	542
Retained earnings	(10)	(10)
Accumulated other comprehensive loss, net of tax	(1,037)	(396)
Total Illinois Power Generating Company Stockholder’s Equity	(505)	136
Noncontrolling interest	3	5
Total Equity	(502)	141
Total Liabilities and Equity	$ 497	$ 1,226

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock, no par value (usd per share)	$ 0	$ 0
Common stock, shares authorized	10,000	10,000
Common stock, shares outstanding	2,000	2,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenues	$ 147	$ 146	$ 343	$ 420
Cost of sales, excluding depreciation expense	(85)	(88)	(212)	(265)
Gross margin	62	58	131	155
Operating and maintenance expense	(34)	(29)	(93)	(104)
Impairment and other charges	(69)	(855)	(736)	(855)
Depreciation and amortization expense	(8)	(25)	(27)	(75)
General and administrative expense	(9)	(4)	(19)	(17)
Operating loss	(58)	(855)	(744)	(896)
Interest expense	(13)	(10)	(32)	(29)
Other income and expense, net	1	0	15	0
Loss before income taxes	(70)	(865)	(761)	(925)
Income tax benefit	4	348	118	373
Net loss	(66)	(517)	(643)	(552)
Less: Net income (loss) attributable to noncontrolling interest	0	2	(2)	(1)
Net loss attributable to Illinois Power Generating Company	$ (66)	$ (519)	$ (641)	$ (551)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (66)	$ (517)	$ (643)		$ (552)
Actuarial gain due to pension plan remeasurement (net of tax benefit of zero, $5, zero, and $5 for each respective period)	0	8	0		8
Reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges (net of tax of zero for each respective period)	0	1	1	[1]	1	[1]
Amortization of unrecognized prior service credit (net of tax of zero for each respective period)	0	0	(1)	[2]	0	[2]
Other comprehensive income (loss), net of tax	0	9	0		9
Comprehensive income (loss)	(66)	(508)	(643)		(543)
Less: Comprehensive income (loss) attributable to noncontrolling interest	0	3	(2)		0
Total comprehensive income (loss) attributable to Illinois Power Generating Company	$ (66)	$ (511)	$ (641)		$ (543)
[1]	Amount related to the reclassification of mark-to-market losses on cash flow hedging activities and was recorded in Interest expense on our unaudited consolidated statements of operations. Please read Note 3—Risk Management, Derivatives and Financial Instruments for further discussion.
[2]	Amounts are associated with our defined benefit pension and other post-employment benefit plans and are included in the computation of net periodic benefit cost (gain). Please read Note 12—Pension and Other Post-Employment Benefits.

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Tax on actuarial loss due to pension plan remeasurement	$ 0	$ 5	$ 0	$ 5
Tax of reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges, net	0	0	0	0
Tax expense of amortization of unrecognized prior service credit and actuarial gain (loss)	$ 0	$ 0	$ 0	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (643)	$ (552)
Adjustments to reconcile net loss to net cash flows from operating activities:
Impairment of long-lived assets	736	855
Depreciation expense	27	75
Gain on sale of assets, net	(14)
Deferred income taxes and investment tax credits, net	(118)	(373)
Other	3	8
Changes in working capital:
Accounts receivable, net	(8)	56
Inventory	37	(15)
Prepayments and other current assets	(1)	(3)
Restricted cash	(6)	0
Accounts payable and accrued liabilities	29	(1)
Other	0	(5)
Net cash provided by operating activities	42	45
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(33)	(43)
Proceeds on sale of assets, net	14	0
Net cash used in investing activities	(19)	(43)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net cash provided by financing activities	0	0
Net increase in cash	23	2
Cash, beginning of year	61	126
Cash, end of period	$ 84	$ 128

Basis of Presentation and Organ

Basis of Presentation and Organization	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Organization	Note 1—Basis of Presentation and Organization The accompanying unaudited consolidated financial statements have been prepared in accordance with the instructions to interim financial reporting as prescribed by the U.S. Securities and Exchange Commission (“SEC”). The year-end consolidated balance sheet data was derived from audited consolidated financial statements but does not include all disclosures required by Generally Accepted Accounting Principles of the United States of America (“GAAP”). The unaudited consolidated financial statements contained in this report include all material adjustments of a normal recurring nature that, in the opinion of management, are necessary for a fair presentation of the results for the interim periods. Certain prior period amounts in our consolidated financial statements have been reclassified to conform to current year presentation. These interim financial statements should be read together with the consolidated financial statements and notes thereto included in our annual report on Form 10-K for the year ended December 31, 2015 , filed with the SEC on March 28, 2016, which we refer to as our “Form 10-K.” Unless the context indicates otherwise, throughout this report, the terms “Genco,” “the Company,” “we,” “us,” “our,” and “ours” are used to refer to Illinois Power Generating Company and its direct and indirect subsidiaries. We are an electric generation subsidiary of Illinois Power Resources, LLC (“IPR”), which is an indirect wholly-owned subsidiary of Dynegy Inc. (“Dynegy”). We are headquartered in Houston, Texas and were incorporated in Illinois in March 2000. We own and operate a merchant generation business in Illinois and have an 80 percent ownership interest in Electric Energy, Inc. (“EEI”). EEI operates merchant electric generation facilities and FERC-regulated transmission facilities in Illinois and Kentucky. We also consolidate our wholly-owned subsidiary, Coffeen and Western Railroad Company, for financial reporting purposes. All significant intercompany transactions have been eliminated. We are organized into a ring-fenced group in order to maintain corporate separateness from Dynegy and its other legal entities. We have an independent director, whose consent is required for certain corporate actions, including material transactions with affiliates. We maintain separate books, records, and bank accounts and separately appoint officers. Furthermore, we pay liabilities from our own funds, conduct business in our own name, and have restrictions on pledging our assets for the benefit of certain other persons. Our $825 million of senior notes (the “Senior Notes”) are non-recourse to Dynegy. As a result of continued weak energy prices, unsold capacity volumes, on-going required maintenance and environmental expenditures as well as consideration of a $300 million debt maturity in 2018, during the second quarter of 2016 we engaged advisors and began a strategic review. While our projected future cash flow is sufficient to cover our obligations through December 31, 2016, we may not have sufficient future operating cash flow to satisfy our debt maturity in 2018, absent a debt refinancing or restructuring. Therefore, there is substantial doubt about our ability to continue as a going concern. On October 14, 2016, we entered into a restructuring support agreement (the “RSA”) with Dynegy and an ad hoc group of our bondholders (“Ad Hoc Group”) to restructure our Senior Notes either through (a) an out-of-court exchange (the “Exchange Offer”) of our Senior Notes or (b) if the conditions to the Exchange Offer are not satisfied or waived, a pre-packaged plan of reorganization for Genco (the “Plan”) filed in a Chapter 11 case under title 11 of the United States Code (the “Bankruptcy Code”). On November 7, 2016, we launched a restructuring transaction with Dynegy with respect to our Senior Notes (the “Restructuring”) in accordance with the terms of the RSA. See Note 13—Subsequent Events .

Accounting Policies

Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Accounting Policies	Note 2—Accounting Policies The accounting policies followed by the Company are set forth in Note 2—Summary of Significant Accounting Policies of the Notes to Consolidated Financial Statements in our Form 10-K. There have been no significant changes to these policies during the nine months ended September 30, 2016 , with the exception of the addition of the restricted cash policy noted below. Use of Estimates. The preparation of consolidated financial statements in conformity with GAAP requires management to make informed estimates and judgments that affect our reported financial position and results of operations based on currently available information. Actual results could differ materially from our estimates. The results of operations for the interim periods presented in this Form 10-Q are not necessarily indicative of the results to be expected for the full year or any other interim period due to seasonal fluctuations in demand for our energy products and services, changes in commodity prices, timing of maintenance and other expenditures, and other factors. Restricted Cash. Restricted cash represents cash that is not readily available for general purpose cash needs. Restricted cash is classified as a current or long-term asset based on the timing and nature of when or how the cash is expected to be used or when the restrictions are expected to lapse. As of September 30, 2016 , we had restricted cash of $6 million classified as current assets related to cash deposits associated with collateral for operating activities. Accounting Standards Adopted During the Current Period Hybrid Financial Instruments. In November 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-16-Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or Equity. The amendments in this ASU clarify how current GAAP should be interpreted in evaluating the economic characteristics and risks of a host contract in a hybrid financial instrument that is issued in the form of a share. Specifically, the amendments clarify that an entity should consider all relevant terms and features, including the embedded derivative feature being evaluated for bifurcation, in evaluating the nature of the host contract. Furthermore, the amendments clarify that no single term or feature would necessarily determine the economic characteristics and risks of the host contract. Rather, the nature of the host contract depends upon the economic characteristics and risks of the entire hybrid financial instrument. The amendments in this ASU also clarify that, in evaluating the nature of a host contract, an entity should assess the substance of the relevant terms and features (i.e., the relative strength of the debt-like or equity-like terms and features given the facts and circumstances) when considering how to weigh those terms and features. The adoption of this ASU on January 1, 2016, did not have an impact on our unaudited consolidated financial statements. Debt Issuance Costs. In April 2015, the FASB issued ASU 2015-03-Interest-Imputation of Interest (Subtopic 835-30). The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update. In August 2015, the FASB issued ASU 2015-15-Interest-Imputation of Interest (Subtopic 835-30). The amendments in this ASU further clarify the guidance provided in ASU 2015-03 to include the presentation of debt issuance costs in relation to line-of-credit arrangements. The amendments state these costs should be presented as an asset and subsequently amortized ratably over the term of the arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. We adopted these ASUs on January 1, 2016, on a retrospective basis affecting presentation on the unaudited consolidated balance sheet for all periods presented. Accordingly, we reclassified unamortized debt issuance costs of $1 million from Prepayments and other current assets and $3 million from Other assets to Long-term debt within our unaudited consolidated balance sheet as of December 31, 2015. Extraordinary and Unusual Items. In January 2015, the FASB issued ASU 2015-01-Income Statement-Extraordinary and Unusual Items (Subtopic 225-20). The amendments in this ASU eliminate from GAAP the concept of extraordinary items and will no longer require separate classification of them within the statement of operations. Presentation and disclosure guidance for items that are unusual in nature or occur infrequently will be retained and will be expanded to include items that are both unusual in nature and infrequently occurring. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU on January 1, 2016, did not have an impact on our unaudited consolidated financial statements. Accounting Standards Not Yet Adopted Statement of Cash Flows. In August 2016, the FASB issued ASU 2016-15-Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. To reduce current and future diversity in practice, the amendments in this ASU provide guidance for several cash flow classification issues identified where current GAAP is either unclear or does not include specific guidance. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. We are currently evaluating any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Credit Losses. In June 2016, the FASB issued ASU 2016-13-Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this ASU require the measurement of all expected credit losses for financial assets, which include trade receivables, held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Compensation. In March 2016, the FASB issued ASU 2016-09-Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments in this ASU simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Leases. In February 2016, the FASB issued ASU 2016-02-Leases (Topic 842). The amendments in this ASU will mainly require lessees to recognize lease assets and lease liabilities, for those leases classified as operating leases under GAAP, in their balance sheet. The lease assets recognized in the balance sheet will represent a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The lease liability recognized in the balance sheet will represent the lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Going Concern. In August 2014, the FASB issued ASU 2014-15-Presentation of Financial Statements-Going Concern (Subtopic 205-40). The amendments in this ASU require management, in connection with preparing financial statements for each annual and interim reporting period, to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Currently, there is no guidance in GAAP about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern or to provide related footnote disclosures. The amendments in this ASU provide that guidance. In doing so, the amendments should reduce diversity in the timing and content of footnote disclosures. The guidance in this ASU is effective for fiscal years ending after December 15, 2016, and interim periods within those fiscal years, beginning after December 15, 2016, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Revenue from Contracts with Customers. In May 2014, the FASB and International Accounting Standards Board jointly issued ASU 2014-09-Revenue from Contracts with Customers (Topic 606). This ASU, and subsequently issued amendments to the standard, develop a common revenue standard for GAAP and International Financial Reporting Standards by removing inconsistencies and weaknesses in revenue requirements, providing a more robust framework for addressing revenue issues, improving comparability of revenue recognition practices, providing more useful information to users of financial statements, and simplifying the preparation of financial statements. The guidance in this ASU and its amendments is effective for interim and annual periods beginning after December 15, 2017, with early adoption permitted for interim and annual periods beginning after December 15, 2016. We are currently evaluating this ASU; however, we do not anticipate that the adoption of this ASU will have a material impact on our unaudited consolidated financial statements.

Risk Management, Derivatives an

Risk Management, Derivatives and Financial Instruments	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Risk Management, Derivatives and Financial Instruments	Note 3—Risk Management, Derivatives and Financial Instruments There were no derivative instruments on our unaudited consolidated balance sheet as of September 30, 2016 , and December 31, 2015 . Impact of Derivatives on the Consolidated Statements of Operations The cumulative amount of pretax net losses on interest rate derivative instruments in Accumulated Other Comprehensive Loss (“AOCL”) was $3 million and $4 million as of September 30, 2016 , and December 31, 2015 , respectively. These interest rate swaps were executed in 2007 as a partial hedge of interest rate risks associated with our April 2008 debt issuance. The loss on the interest rate swaps is currently being amortized out of AOCL into our consolidated statements of operations over a 10 -year period that began in April 2008; however, upon the successful completion of our debt restructure or Chapter 11 bankruptcy, the remaining balance of $3 million will be written off. Please see Note 13—Subsequent Events for further discussion on the debt restructure. Financial Instruments Not Designated as Hedges. There was no impact of mark-to-market gains (losses) on our unaudited consolidated statements of operations for the three and nine months ended September 30, 2016 and 2015 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 4—Fair Value Measurements Non-recurring Measurements. In the second quarter of 2016, as a result of impairment testing, we measured our Newton facility at fair value. Please read Note 7—Property, Plant and Equipment for further discussion. The valuation method used to determine the impairment charge is classified as Level 3 within the fair value hierarchy. Fair Value of Financial Instruments. We have determined the estimated fair value of our financial instruments using available market information and selected valuation methodologies. Considerable judgment is required in interpreting market data to develop the estimates of fair value. The use of different market assumptions or valuation methodologies could have a material effect on the estimated fair value amounts. The carrying values of financial assets and liabilities (cash, accounts receivable, restricted cash, and accounts payable) not presented in the table below approximate fair values due to the short-term maturities of these instruments. Unless otherwise noted, the fair value of debt as reflected in the table has been calculated based on the average of certain available broker quotes as of September 30, 2016 and December 31, 2015 , respectively. All fair values presented below are classified within Level 2 of the fair value hierarchy. Please see Note 13—Subsequent Events . September 30, 2016 December 31, 2015 (amounts in millions) Carrying Amount Fair Value Carrying Amount Fair Value 7.00% Senior Notes Series H, due 2018 (1) $ (300 ) $ (119 ) $ (299 ) $ (204 ) 6.30% Senior Notes Series I, due 2020 (1) $ (249 ) $ (99 ) $ (249 ) $ (148 ) 7.95% Senior Notes Series F, due 2032 (1) $ (272 ) $ (107 ) $ (272 ) $ (162 ) __________________________________________ (1) Combined carrying amounts include unamortized discounts and debt issuance costs of $4 million and $5 million as of September 30, 2016 and December 31, 2015 , respectively. Please read Note 8—Debt for further discussion.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Accumulated Other Comprehensive Loss	Note 5—Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss, net of tax, by component are as follows: Nine Months Ended September 30, (amounts in millions) 2016 2015 Beginning of year $ (10 ) $ (16 ) Other comprehensive income (loss) before reclassifications: Actuarial gain due to pension plan remeasurement (net of tax benefit of zero and $5, respectively) — 5 Amounts reclassified from accumulated other comprehensive loss: Reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges (net of tax of zero and zero, respectively) (1) 1 1 Amortization of unrecognized prior service credit (net of tax of zero and zero, respectively) (2) (1 ) — Net current period other comprehensive income (loss), net of tax — 6 End of period $ (10 ) $ (10 ) _______________________________________ (1) Amount related to the reclassification of mark-to-market losses on cash flow hedging activities and was recorded in Interest expense on our unaudited consolidated statements of operations. Please read Note 3—Risk Management, Derivatives and Financial Instruments for further discussion. (2) Amounts are associated with our defined benefit pension and other post-employment benefit plans and are included in the computation of net periodic benefit cost (gain). Please read Note 12—Pension and Other Post-Employment Benefits .

Inventory

Inventory	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventory	Note 6—Inventory A summary of our inventories is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Materials and supplies $ 30 $ 30 Coal 65 102 Fuel oil 1 1 Total $ 96 $ 133

Property, Plant and Equipment P

Property, Plant and Equipment Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Note 7—Property, Plant and Equipment A summary of our property, plant and equipment is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Power generation $ 510 $ 1,511 Building and improvements 51 212 Office and other equipment 22 27 Property, plant and equipment 583 1,750 Accumulated depreciation (376 ) (813 ) Property, plant and equipment, net $ 207 $ 937 Impairments Newton. In the second quarter of 2016, due to the recent MISO auction results and the impact of the shutdown of one of our Newton facility units, we performed an impairment analysis on our plants. We performed step one of the impairment analysis using undiscounted cash flows for the estimated useful lives of the facilities and determined the book value of the Newton facility would not be recovered. We performed step two of the impairment analysis using a discounted cash flow model, utilizing a 13 percent discount rate, and assuming normal operations for the estimated useful lives of the facilities. For the model, gross margin was based on forward commodity market prices obtained from third party quotations for the years 2016 through 2018. For the years 2019 through 2025, we used commodity and capacity price curves developed internally utilizing supply and demand factors. We also used management’s forecasts of operations and maintenance expense, general and administrative expense, and capital expenditures for the years 2016 through 2025 and assumed a 2.5 percent growth rate thereafter, based upon management’s view of future conditions. The model resulted in a fair value of the Newton facility of $71 million , resulting in an impairment charge of $667 million recorded to Impairments in our unaudited consolidated statements of operations for the nine months ended September 30, 2016 . The valuation is classified as Level 3 within the fair value hierarchy. On September 2, 2016, IPH and Ameren Energy Medina Valley Cogen, LLC filed a motion with the Illinois Pollution Control Board (“IPCB”) to terminate the variance from the SO 2 annual emission rate limits provided in the Illinois Multi-Pollutant Standards (“MPS”). IPH retired Newton Unit 2 on September 15, 2016. This retirement, along with the use of dispatch management, will allow IPH to continue to comply with the MPS SO 2 limits, thereby eliminating the need for the variance. As a result, the flue gas desulfurization (“FGD”) systems construction project at our Newton generation facility was terminated. On October 27, 2016, the IPCB granted the motion to terminate the variance. Capitalized costs not yet placed into service related to the project of $69 million were written-off and recorded to Impairments in our unaudited consolidated statements of operations for the three and nine months ended September 30, 2016 . Coffeen. During the third quarter of 2015, we impaired the book value of our Coffeen facility and recorded an impairment charge of $855 million to Impairments in our unaudited consolidated statements of operations for the three and nine months ended September 30, 2015 . See Note 3—Impairments in our Form 10-K for further discussion.

Debt

Debt	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt	Note 8—Debt A summary of our long-term debt is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Unsecured notes: 7.00% Senior Notes Series H, due 2018 (1) $ 300 $ 300 6.30% Senior Notes Series I, due 2020 (1) 250 250 7.95% Senior Notes Series F, due 2032 (1) 275 275 825 825 Unamortized discount and debt issuance costs (2) (4 ) (5 ) Total Long-term debt (3) $ 821 $ 820 _______________________________________ (1) On October 14, 2016, we entered into the RSA with Dynegy and the Ad Hoc Group to restructure our Senior Notes. On November 7, 2016, we launched the Restructuring in accordance with the terms of the RSA. See Note 13—Subsequent Events —Genco Debt Restructure for further discussion. (2) Includes $4 million related to the reclassification of unamortized debt issuance costs as of December 31, 2015. Please read Note 2—Accounting Policies for further discussion. (3) Our Senior Notes are non-recourse to Dynegy. Indenture Provisions and Other Covenants Certain of our financial obligations and all of our Senior Notes include provisions which, if not met, could require early payment, additional collateral support, or similar actions. The trigger events include the violation of covenants, defaults on scheduled principal or interest payments, including any indebtedness to the extent linked to it by reason of cross-default or cross-acceleration provisions, insolvency events, and acceleration of other financial obligations. At September 30, 2016 , we were in compliance with the provisions and covenants contained within our indenture. Our indenture also includes provisions that require us to maintain certain interest coverage and debt-to-capital ratios in order for us to pay dividends, to make principal or interest payments on subordinated borrowings, to make loans to or investments in affiliates, or to incur additional external, third-party indebtedness. The following table summarizes these required ratios: Required Ratio Restricted payment interest coverage ratio (1) ≥1.75 Additional indebtedness interest coverage ratio (2) ≥2.50 Additional indebtedness debt-to-capital ratio (2) ≤60% _______________________________________ (1) As of the date of a restricted payment, as defined, the minimum ratio must have been achieved for the most recently ended four fiscal quarters and projected by management to be achieved for each of the subsequent four six-month periods. (2) Ratios must be computed on a pro forma basis considering the additional indebtedness to be incurred and the related interest expense. Other borrowings from external, third-party sources are included in the definition of indebtedness and are subject to these incurrence tests. Based on September 30, 2016 calculations, we did not meet the ratios required for us to pay dividends and borrow additional funds from external, third party sources.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 9—Commitments and Contingencies Contingencies We record accruals for estimated losses from contingencies when available information indicates that a loss is probable and the amount of the loss, or range of loss, can be reasonably estimated. In addition, we disclose matters for which management believes a material loss is reasonably possible. Management assesses matters based on current information and makes judgments concerning their potential outcome, giving consideration to the nature of the claim, the amount, if any, the nature of damages sought, and the probability of success. Management regularly reviews all new information with respect to such contingencies and adjusts its assessments and estimates of such contingencies accordingly. Because litigation is subject to inherent uncertainties including unfavorable rulings or developments, it is possible that the ultimate resolution of our legal proceedings could involve amounts that are different from our currently recorded accruals, and that such differences could be material. We are party to other routine proceedings arising in the ordinary course of business. Any accruals or estimated losses related to these matters are not material. In management’s judgment, the ultimate resolution of these matters will not have a material effect on our financial condition, results of operations, or cash flows. MISO 2015-2016 Planning Resource Auction. In May 2015, three complaints were filed at FERC regarding the Zone 4 results for the 2015-2016 Planning Resource Auction (“PRA”) conducted by MISO. The Newton, Coffeen, and Joppa facilities were offered into Zone 4 in the 2015-2016 PRA. The complainants, Public Citizen, Inc., the Illinois Attorney General, and Southwestern Electric Cooperative, In c., have challenged the results of the PRA as unjust and unreasonable, requested rate relief/refunds, and requested changes to the MISO PRA structure going forward. Complainants have also alleged that Dynegy may have engaged in economic or physical withholding in Zone 4 constituting market manipulation in the 2015-2016 PRA. The Independent Market Monitor for MISO (“MISO IMM”), which was responsible for monitoring the MISO 2015-2016 PRA, determined that all offers were competitive and that no physical or economic withholding occurred. The MISO IMM also stated, in a filing responding to the complaints, that there is no basis for the proposed remedies. Dynegy disputes the allegations and will defend its actions vigorously. Dynegy filed its Answer to these complaints. In addition, the Illinois Industrial Energy Consumers filed a complaint at FERC against MISO on June 30, 2015 requesting prospective changes to the MISO tariff. Dynegy also responded to this complaint. On October 1, 2015, FERC issued an order of non-public, formal investigation, stating that shortly after the conclusion of the 2015-2016 PRA, FERC’s Office of Enforcement began a non-public informal investigation into whether market manipulation or other potential violations of FERC orders, rules, and regulations occurred before or during the PRA (the “Order”). The Order noted that the investigation is ongoing, and that the order converting the informal, non-public investigation to a formal, non-public investigation does not indicate that FERC has determined that any entity has engaged in market manipulation or otherwise violated any FERC order, rule, or regulation. Further, FERC held a Staff-led technical conference on October 20, 2015, to obtain further information concerning potential changes to the MISO PRA structure going forward, including proposals made by complainants. The technical conference did not address the ongoing Office of Enforcement investigation. On December 31, 2015, FERC issued an order on the complaints requiring a number of prospective changes to the MISO tariff provisions associated with calculating Initial Reference Levels and Local Clearing Requirements, effective as of the 2016-2017 PRA. Under the order, FERC found that the existing tariff provision which bases Initial Reference Levels for capacity supply offers on the estimated opportunity cost of exporting capacity to a neighboring region (for example, PJM) are no longer just and reasonable. Accordingly, FERC required MISO to set the Initial Reference Level for capacity at $0 per MW-day for the 2016-2017 PRA. Capacity suppliers may also request a facility-specific reference level from the MISO IMM. The order did not address the arguments of the complainants regarding the 2015-2016 PRA, and stated that those issues remain under consideration and will be addressed in a future order. New Source Review and CAA Matters New Source Review. Since 1999, the EPA has been engaged in a nationwide enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the New Source Review and New Source Performance Standard provisions under the CAA when the plants implemented modifications. The EPA’s initiative focuses on whether projects performed at power plants triggered various permitting requirements, including the need to install pollution control equipment. CAA Section 114 Information Requests. Commencing in 2005, we received a series of information requests from the EPA pursuant to Section 114(a) of the CAA. The requests sought detailed operating and maintenance history data with respect to the Coffeen, Newton, and Joppa facilities. In August 2012, the EPA issued a Notice of Violation (“NOV”) alleging that projects performed in 1997, 2006, and 2007 at the Newton facility violated Prevention of Significant Deterioration, Title V permitting, and other requirements. The NOV remains unresolved. We believe our defenses to the allegations described in the NOV are meritorious. A decision by the U.S. Court of Appeals for the Seventh Circuit in 2013 held that similar claims older than five years were barred by the statute of limitations. This decision may provide an additional defense to the allegations in the NOV. Ultimate resolution of any of these CAA matters could have a material adverse impact on our future financial condition, results of operations, and cash flows. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and penalties. At this time we are unable to make a reasonable estimate of the possible costs, or range of costs, that might be incurred to resolve these matters. Groundwater. Groundwater monitoring results indicate that the coal combustion residuals (“CCR”) surface impoundments at the Newton, Coffeen, and Joppa facilities potentially impact onsite groundwater. In 2012, the Illinois EPA (“IEPA”) issued violation notices alleging violations of groundwater standards at the Newton and Coffeen facilities’ CCR surface impoundments. In April 2015, we submitted an assessment monitoring report to the IEPA concerning previously reported groundwater quality standard exceedances at the Newton facility’s active CCR landfill. The report identifies the Newton facility’s inactive unlined landfill as the likely source of the exceedances and recommends various measures to minimize the effects of that source on the groundwater monitoring results of the active landfill. In August 2016, the IEPA approved the report. If remediation measures concerning groundwater are necessary at any of our facilities, we may incur significant costs that could have a material adverse effect on our financial condition, results of operations, and cash flows. At this time we cannot reasonably estimate the costs, or range of costs, of remediation, if any, that ultimately may be required. Commitments In conducting our operations, we have routinely entered into long-term commodity purchase and sale commitments, as well as agreements that commit future cash flow to the lease or acquisition of assets used in our businesses. These commitments have been typically associated with commodity supply arrangements, capital projects, reservation charges associated with firm transmission, transportation, storage and leases for office space, equipment, design and construction, plant sites, and power generation assets. Environmental Compliance Obligations. On September 2, 2016, IPH and Ameren Energy Medina Valley Cogen, LLC filed a motion with the IPCB to terminate the variance from the SO 2 annual emission rate limits provided in the MPS. IPH retired Newton Unit 2 on September 15, 2016. This retirement, along with the use of dispatch management, will allow IPH to continue to comply with the MPS SO 2 limits, thereby eliminating the need for the variance. As a result, the FGD systems construction project at our Newton generation facility was terminated. On October 27, 2016, the IPCB granted the motion to terminate the variance. Indemnifications and Guarantees In the ordinary course of business, we routinely enter into contractual agreements that contain various representations, warranties, indemnifications, and guarantees. Examples of such agreements include, but are not limited to, service agreements, equipment purchase agreements, engineering and technical service agreements, asset sales agreements, and procurement and construction contracts. Some agreements contain indemnities that cover the other party’s negligence or limit the other party’s liability with respect to third-party claims, in which event we will effectively be indemnifying the other party. Virtually all such agreements contain representations or warranties that are covered by indemnifications against the losses incurred by the other parties in the event such representations and warranties are false. While there is always the possibility of a loss related to such representations, warranties, indemnifications, and guarantees in our contractual agreements, and such loss could be significant, management considers the probability of loss to be remote. Guaranty Agreement. Genco has provided an uncapped Guaranty Agreement of certain credit support obligations and tax and environmental indemnification obligations of IPH under a transaction agreement with Ameren Corporation (“Ameren”). Certain of the guaranteed obligations under the Guaranty Agreement will survive indefinitely.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Note 10—Related Party Transactions We have engaged in, and may in the future engage in, affiliate transactions in the normal course of business. These transactions primarily consist of power purchases and sales, and services received or rendered. For a discussion of our material related party agreements, please read Note 11 — Related Party Transactions of the Form 10-K. The following table summarizes the affiliate accounts receivable and payable on our unaudited consolidated balance sheets: September 30, 2016 December 31, 2015 (amounts in millions) Accounts Receivable, Affiliates Accounts Payable, Affiliates Accounts Receivable, Affiliates Accounts Payable, Affiliates Power supply agreements $ 60 $ — $ 54 $ — Services agreement — 22 — 5 Tax sharing agreement — 1 — 3 Other (1) 3 17 — 10 Total $ 63 $ 40 $ 54 $ 18 __________________________________________ (1) At September 30, 2016 and December 31, 2015 , approximately $14 million and $10 million , respectively, of the accounts payable, affiliates balance is comprised of reimbursable employee benefits paid by a Dynegy subsidiary on behalf of Genco. The following table presents the impact of related party transactions on our unaudited consolidated statements of operations for the three and nine months ended September 30, 2016 and 2015 . It is based primarily on the agreements discussed below and in Note 11 — Related Party Transactions of the Form 10-K. Three Months Ended September 30, Nine Months Ended September 30, (amounts in millions) Income Statement Line Item 2016 2015 2016 2015 Power supply agreements Revenues $ 147 $ 146 $ 343 $ 418 Services agreement Operating and maintenance expense $ 7 $ 7 $ 23 $ 26 Power Supply Agreements Genco has a PSA with Illinois Power Marketing Company (“IPM”), a subsidiary of IPR, whereby IPM purchases all of the capacity and energy available from Genco’s generation fleet. IPM entered into a similar PSA with Illinois Power Resources Generating, LLC (“IPRG”). Under the PSAs, IPM revenues are allocated between Genco and IPRG based on reimbursable expenses and generation of each entity. The reimbursable expenses used in the calculation of revenues allocated under the Genco and IPRG PSAs include operation costs in addition to depreciation and interest on debt. Each PSA will continue through December 31, 2022, and from year to year thereafter. Either party to the respective PSA may elect to terminate the PSA by providing the other party with no less than six months advance written notice. EEI has a PSA with IPM, whereby IPM purchases all of the capacity and energy available from EEI’s generation fleet. With limited exceptions, the price that IPM pays for capacity is the MISO Local Resources Zone 4 clearing price. IPM pays spot market prices for the associated energy. In addition, EEI will at times purchase energy from IPM to fulfill obligations to a non-affiliated party. The PSA will continue through December 31, 2022. Either party to the PSA may elect to terminate the PSA by providing the other party with no less than six months advance written notice. Collateral Agreement Genco has a collateral agreement with IPM pursuant to which IPM may require Genco to provide collateral to IPM to secure obligations of IPM applicable to Genco’s assets. The initial collateral limit for Genco is $15 million and IPM can demand an additional $7.5 million for a total limit not to exceed $22.5 million . There have been no amounts provided under this agreement as of September 30, 2016 . Services Agreement Dynegy and certain of its subsidiaries (collectively, the “Providers”) provide certain services (the “Services”) to IPH, and certain of its consolidated subsidiaries (collectively, the “Recipients”), which includes us and EEI, under a services agreement (the “Services Agreement”). The Providers act as agents for the Recipients for the limited purpose of providing the Services set forth in the Services Agreement. Prior to the beginning of each fiscal year in which Services are to be provided pursuant to the Services Agreement, the Providers and the Recipients agree on a budget for the Services, outlining, among other items, the contemplated scope of the Services to be provided in the following fiscal year and the cost of providing the Services. The Recipients will pay the Providers an annual management fee as agreed in the budget. We believe this is a reasonable method of allocating the costs of the Services to us and provides an appropriate reflection of the costs we would have incurred if we operated as an unaffiliated entity. Effective December 31, 2015, we amended the Services Agreement to provide that payments due in 2016 to Dynegy for services incurred may be deferred. Any deferred payments, and associated interest, will be reflected as an affiliate payable to be settled at the discretion of Dynegy or us. Tax Sharing Agreement We are included in the consolidated tax returns of Dynegy. Under U.S. federal income tax law, Dynegy files consolidated income tax returns for itself and its subsidiaries. Dynegy is responsible for the federal tax liabilities of its subsidiaries which include the income and business activities of the ring-fenced entities and Dynegy’s other affiliates. Genco and Dynegy entered into a tax sharing agreement on December 2, 2013 that provides that we recognize taxes based on a separate company income tax return basis, as defined in the agreement. The tax sharing arrangement provides that accumulated taxes payable to Dynegy, and any associated interest, be settled at the discretion of Dynegy or us.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Note 11—Income Taxes We compute our quarterly taxes under the effective tax rate method based on applying an anticipated annual effective rate to our year-to-date income or loss, except for significant, unusual, or extraordinary transactions. Our effective tax rate of 16% is lower than the statutory rate of 35% as a result of the recognition of a valuation allowance primarily caused by the impairment of our Newton facility.

Pension and Other Post-Employme

Pension and Other Post-Employment Benefits	9 Months Ended
	Sep. 30, 2016
Postemployment Benefits [Abstract]
Pension and Other Post-Employment Benefits	Note 12—Pension and Other Post-Employment Benefits We offer defined benefit pension and other post-employment benefit plans covering our employees. Separately, our EEI employees and retirees participate in EEI’s single-employer pension and other post-employment plans. We consolidate EEI; therefore, EEI’s plans are reflected in our pension and other post-employment balances and disclosures. Please read Note 14—Savings and Pension and Other Post-Retirement Benefit Plans in our Form 10-K for further discussion. In August 2015, we finalized certain new collective bargaining agreements that resulted in amendments to certain post-employment benefit plans. As a result of these amendments, we remeasured our benefit obligations and the funded status of the affected plans using inputs as of July 31, 2015. We recorded a gain through accumulated other comprehensive loss and decreased our net liability by approximately $13 million during the third quarter of 2015. Components of Net Periodic Benefit Cost (Gain). The following table presents the components of our net periodic benefit cost (gain) of the EEI pension and other post-employment benefit plans for the three and nine months ended September 30, 2016 and 2015 . Also reflected is an allocation of net periodic benefit cost (gain) from our participation in Dynegy’s single-employer pension and other post-employment plans for the three and nine months ended September 30, 2016 and 2015 . Pension Benefits Other Benefits Three Months Ended September 30, (amounts in millions) 2016 2015 2016 2015 Service cost $ — $ 1 $ — $ — Interest cost — — — 1 Expected return on plan assets (1 ) (1 ) — (1 ) Amortization of: Prior service credit 1 1 (1 ) (1 ) Net periodic benefit cost (gain) $ — $ 1 $ (1 ) $ (1 ) Pension Benefits Other Benefits Nine Months Ended September 30, (amounts in millions) 2016 2015 2016 2015 Service cost $ 2 $ 2 $ — $ 1 Interest cost 2 2 1 2 Expected return on plan assets (3 ) (3 ) (2 ) (3 ) Amortization of: Prior service credit 1 1 (2 ) (1 ) Net periodic benefit cost (gain) $ 2 $ 2 $ (3 ) $ (1 )

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Event	Note 13—Subsequent Events Genco Debt Restructure On October 14, 2016, we entered into the RSA with Dynegy and the Ad Hoc Group to restructure our Senior Notes either through (a) the Exchange Offer of our Senior Notes or (b) if the conditions to the Exchange Offer are not satisfied or waived (as discussed below), the Plan filed in a Chapter 11 case under the Bankruptcy code. On November 7, 2016, we launched the Restructuring in accordance with the terms of the RSA. Pursuant to the Exchange Offer, the $825 million of our existing Senior Notes will be exchanged for up to (i) $210 million in new seven-year Dynegy unsecured notes, (ii) $130 million of cash consideration (subject to reductions for interest payments) funded with existing IPH cash balances and an expected return of collateral of approximately $61 million , and (iii) 10 million new Dynegy warrants with a seven -year term for an exercise price of $35 per share. In addition, the Exchange Offer includes a solicitation of consents to proposed amendments to the indenture governing our Senior Notes. The Exchange Offer period under the Restructuring will expire on December 6, 2016, unless extended by Dynegy. If the restructuring is consummated pursuant to the Plan, it is expected that participating non-accredited investors will be entitled to a cash payment in lieu of their pro rata allocation of the notes and warrants described above. Solicitation with respect to the Exchange Offer will occur simultaneously with the solicitation of the Plan. We will continue making interest payments on our Senior Notes, with payments after September 30, 2016 netted against the proposed cash consideration. Genco, Dynegy and the Ad Hoc Group agreed that holders of our Senior Notes who entered into the RSA on or before October 21, 2016, will be paid their pro rata share of $9 million in cash upon consummation of a restructuring, with such pro rata share determined as the proportion that the amount of our Senior Notes held by each such holder bears to the aggregate amount of our Senior Notes held by all holders entitled to receive a share of the $9 million . If holders of 97 percent or more of the aggregate principal amount of our Senior Notes participate in the Exchange Offer and the other conditions thereto are satisfied, we intend to consummate the restructuring out of court. If holders of less than 97 percent of the aggregate principal amount of our Senior Notes, but a majority in number of the holders who have voted on the Plan and who hold at least 66.7 percent in the aggregate amount of our Senior Notes vote to accept the Plan, the parties to the RSA intend to consummate the restructuring through a prepackaged Chapter 11 filing of Genco. As of October 24, 2016, the Ad Hoc Group of our bondholders represents approximately 70 percent of the $825 million of our Senior Notes. See Note 8—Debt for further discussion regarding the Senior Notes.

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Note 1—Basis of Presentation and Organization The accompanying unaudited consolidated financial statements have been prepared in accordance with the instructions to interim financial reporting as prescribed by the U.S. Securities and Exchange Commission (“SEC”). The year-end consolidated balance sheet data was derived from audited consolidated financial statements but does not include all disclosures required by Generally Accepted Accounting Principles of the United States of America (“GAAP”). The unaudited consolidated financial statements contained in this report include all material adjustments of a normal recurring nature that, in the opinion of management, are necessary for a fair presentation of the results for the interim periods. Certain prior period amounts in our consolidated financial statements have been reclassified to conform to current year presentation. These interim financial statements should be read together with the consolidated financial statements and notes thereto included in our annual report on Form 10-K for the year ended December 31, 2015 , filed with the SEC on March 28, 2016, which we refer to as our “Form 10-K.” Unless the context indicates otherwise, throughout this report, the terms “Genco,” “the Company,” “we,” “us,” “our,” and “ours” are used to refer to Illinois Power Generating Company and its direct and indirect subsidiaries. We are an electric generation subsidiary of Illinois Power Resources, LLC (“IPR”), which is an indirect wholly-owned subsidiary of Dynegy Inc. (“Dynegy”). We are headquartered in Houston, Texas and were incorporated in Illinois in March 2000. We own and operate a merchant generation business in Illinois and have an 80 percent ownership interest in Electric Energy, Inc. (“EEI”). EEI operates merchant electric generation facilities and FERC-regulated transmission facilities in Illinois and Kentucky. We also consolidate our wholly-owned subsidiary, Coffeen and Western Railroad Company, for financial reporting purposes. All significant intercompany transactions have been eliminated. We are organized into a ring-fenced group in order to maintain corporate separateness from Dynegy and its other legal entities. We have an independent director, whose consent is required for certain corporate actions, including material transactions with affiliates. We maintain separate books, records, and bank accounts and separately appoint officers. Furthermore, we pay liabilities from our own funds, conduct business in our own name, and have restrictions on pledging our assets for the benefit of certain other persons.
Use of Estimates	Use of Estimates. The preparation of consolidated financial statements in conformity with GAAP requires management to make informed estimates and judgments that affect our reported financial position and results of operations based on currently available information. Actual results could differ materially from our estimates. The results of operations for the interim periods presented in this Form 10-Q are not necessarily indicative of the results to be expected for the full year or any other interim period due to seasonal fluctuations in demand for our energy products and services, changes in commodity prices, timing of maintenance and other expenditures, and other factors.
Restricted Cash	Restricted Cash. Restricted cash represents cash that is not readily available for general purpose cash needs. Restricted cash is classified as a current or long-term asset based on the timing and nature of when or how the cash is expected to be used or when the restrictions are expected to lapse. As of September 30, 2016 , we had restricted cash of $6 million classified as current assets related to cash deposits associated with collateral for operating activities.
Accounting Standards Adopted During the Current Period	Accounting Standards Adopted During the Current Period Hybrid Financial Instruments. In November 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-16-Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or Equity. The amendments in this ASU clarify how current GAAP should be interpreted in evaluating the economic characteristics and risks of a host contract in a hybrid financial instrument that is issued in the form of a share. Specifically, the amendments clarify that an entity should consider all relevant terms and features, including the embedded derivative feature being evaluated for bifurcation, in evaluating the nature of the host contract. Furthermore, the amendments clarify that no single term or feature would necessarily determine the economic characteristics and risks of the host contract. Rather, the nature of the host contract depends upon the economic characteristics and risks of the entire hybrid financial instrument. The amendments in this ASU also clarify that, in evaluating the nature of a host contract, an entity should assess the substance of the relevant terms and features (i.e., the relative strength of the debt-like or equity-like terms and features given the facts and circumstances) when considering how to weigh those terms and features. The adoption of this ASU on January 1, 2016, did not have an impact on our unaudited consolidated financial statements. Debt Issuance Costs. In April 2015, the FASB issued ASU 2015-03-Interest-Imputation of Interest (Subtopic 835-30). The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update. In August 2015, the FASB issued ASU 2015-15-Interest-Imputation of Interest (Subtopic 835-30). The amendments in this ASU further clarify the guidance provided in ASU 2015-03 to include the presentation of debt issuance costs in relation to line-of-credit arrangements. The amendments state these costs should be presented as an asset and subsequently amortized ratably over the term of the arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. We adopted these ASUs on January 1, 2016, on a retrospective basis affecting presentation on the unaudited consolidated balance sheet for all periods presented. Accordingly, we reclassified unamortized debt issuance costs of $1 million from Prepayments and other current assets and $3 million from Other assets to Long-term debt within our unaudited consolidated balance sheet as of December 31, 2015. Extraordinary and Unusual Items. In January 2015, the FASB issued ASU 2015-01-Income Statement-Extraordinary and Unusual Items (Subtopic 225-20). The amendments in this ASU eliminate from GAAP the concept of extraordinary items and will no longer require separate classification of them within the statement of operations. Presentation and disclosure guidance for items that are unusual in nature or occur infrequently will be retained and will be expanded to include items that are both unusual in nature and infrequently occurring. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU on January 1, 2016, did not have an impact on our unaudited consolidated financial statements.
Accounting Standards Not Yet Adopted	Accounting Standards Not Yet Adopted Statement of Cash Flows. In August 2016, the FASB issued ASU 2016-15-Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. To reduce current and future diversity in practice, the amendments in this ASU provide guidance for several cash flow classification issues identified where current GAAP is either unclear or does not include specific guidance. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. We are currently evaluating any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Credit Losses. In June 2016, the FASB issued ASU 2016-13-Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this ASU require the measurement of all expected credit losses for financial assets, which include trade receivables, held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Compensation. In March 2016, the FASB issued ASU 2016-09-Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments in this ASU simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Leases. In February 2016, the FASB issued ASU 2016-02-Leases (Topic 842). The amendments in this ASU will mainly require lessees to recognize lease assets and lease liabilities, for those leases classified as operating leases under GAAP, in their balance sheet. The lease assets recognized in the balance sheet will represent a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The lease liability recognized in the balance sheet will represent the lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis. The guidance in this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Going Concern. In August 2014, the FASB issued ASU 2014-15-Presentation of Financial Statements-Going Concern (Subtopic 205-40). The amendments in this ASU require management, in connection with preparing financial statements for each annual and interim reporting period, to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Currently, there is no guidance in GAAP about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern or to provide related footnote disclosures. The amendments in this ASU provide that guidance. In doing so, the amendments should reduce diversity in the timing and content of footnote disclosures. The guidance in this ASU is effective for fiscal years ending after December 15, 2016, and interim periods within those fiscal years, beginning after December 15, 2016, with early adoption permitted. We are currently evaluating this ASU and any potential impacts the adoption of this ASU will have on our unaudited consolidated financial statements. Revenue from Contracts with Customers. In May 2014, the FASB and International Accounting Standards Board jointly issued ASU 2014-09-Revenue from Contracts with Customers (Topic 606). This ASU, and subsequently issued amendments to the standard, develop a common revenue standard for GAAP and International Financial Reporting Standards by removing inconsistencies and weaknesses in revenue requirements, providing a more robust framework for addressing revenue issues, improving comparability of revenue recognition practices, providing more useful information to users of financial statements, and simplifying the preparation of financial statements. The guidance in this ASU and its amendments is effective for interim and annual periods beginning after December 15, 2017, with early adoption permitted for interim and annual periods beginning after December 15, 2016. We are currently evaluating this ASU; however, we do not anticipate that the adoption of this ASU will have a material impact on our unaudited consolidated financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Liabilities	The carrying values of financial assets and liabilities (cash, accounts receivable, restricted cash, and accounts payable) not presented in the table below approximate fair values due to the short-term maturities of these instruments. Unless otherwise noted, the fair value of debt as reflected in the table has been calculated based on the average of certain available broker quotes as of September 30, 2016 and December 31, 2015 , respectively. All fair values presented below are classified within Level 2 of the fair value hierarchy. Please see Note 13—Subsequent Events . September 30, 2016 December 31, 2015 (amounts in millions) Carrying Amount Fair Value Carrying Amount Fair Value 7.00% Senior Notes Series H, due 2018 (1) $ (300 ) $ (119 ) $ (299 ) $ (204 ) 6.30% Senior Notes Series I, due 2020 (1) $ (249 ) $ (99 ) $ (249 ) $ (148 ) 7.95% Senior Notes Series F, due 2032 (1) $ (272 ) $ (107 ) $ (272 ) $ (162 ) __________________________________________ (1) Combined carrying amounts include unamortized discounts and debt issuance costs of $4 million and $5 million as of September 30, 2016 and December 31, 2015 , respectively. Please read Note 8—Debt for further discussion.

Accumulated Other Comprehensi23

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive loss, net of tax, by component are as follows: Nine Months Ended September 30, (amounts in millions) 2016 2015 Beginning of year $ (10 ) $ (16 ) Other comprehensive income (loss) before reclassifications: Actuarial gain due to pension plan remeasurement (net of tax benefit of zero and $5, respectively) — 5 Amounts reclassified from accumulated other comprehensive loss: Reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges (net of tax of zero and zero, respectively) (1) 1 1 Amortization of unrecognized prior service credit (net of tax of zero and zero, respectively) (2) (1 ) — Net current period other comprehensive income (loss), net of tax — 6 End of period $ (10 ) $ (10 ) _______________________________________ (1) Amount related to the reclassification of mark-to-market losses on cash flow hedging activities and was recorded in Interest expense on our unaudited consolidated statements of operations. Please read Note 3—Risk Management, Derivatives and Financial Instruments for further discussion. (2) Amounts are associated with our defined benefit pension and other post-employment benefit plans and are included in the computation of net periodic benefit cost (gain). Please read Note 12—Pension and Other Post-Employment Benefits .

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	A summary of our inventories is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Materials and supplies $ 30 $ 30 Coal 65 102 Fuel oil 1 1 Total $ 96 $ 133

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	A summary of our property, plant and equipment is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Power generation $ 510 $ 1,511 Building and improvements 51 212 Office and other equipment 22 27 Property, plant and equipment 583 1,750 Accumulated depreciation (376 ) (813 ) Property, plant and equipment, net $ 207 $ 937

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	A summary of our long-term debt is as follows: (amounts in millions) September 30, 2016 December 31, 2015 Unsecured notes: 7.00% Senior Notes Series H, due 2018 (1) $ 300 $ 300 6.30% Senior Notes Series I, due 2020 (1) 250 250 7.95% Senior Notes Series F, due 2032 (1) 275 275 825 825 Unamortized discount and debt issuance costs (2) (4 ) (5 ) Total Long-term debt (3) $ 821 $ 820 _______________________________________ (1) On October 14, 2016, we entered into the RSA with Dynegy and the Ad Hoc Group to restructure our Senior Notes. On November 7, 2016, we launched the Restructuring in accordance with the terms of the RSA. See Note 13—Subsequent Events —Genco Debt Restructure for further discussion. (2) Includes $4 million related to the reclassification of unamortized debt issuance costs as of December 31, 2015. Please read Note 2—Accounting Policies for further discussion. (3) Our Senior Notes are non-recourse to Dynegy.
Schedule of Required Ratios	The following table summarizes these required ratios: Required Ratio Restricted payment interest coverage ratio (1) ≥1.75 Additional indebtedness interest coverage ratio (2) ≥2.50 Additional indebtedness debt-to-capital ratio (2) ≤60% _______________________________________ (1) As of the date of a restricted payment, as defined, the minimum ratio must have been achieved for the most recently ended four fiscal quarters and projected by management to be achieved for each of the subsequent four six-month periods. (2) Ratios must be computed on a pro forma basis considering the additional indebtedness to be incurred and the related interest expense. Other borrowings from external, third-party sources are included in the definition of indebtedness and are subject to these incurrence tests.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following table summarizes the affiliate accounts receivable and payable on our unaudited consolidated balance sheets: September 30, 2016 December 31, 2015 (amounts in millions) Accounts Receivable, Affiliates Accounts Payable, Affiliates Accounts Receivable, Affiliates Accounts Payable, Affiliates Power supply agreements $ 60 $ — $ 54 $ — Services agreement — 22 — 5 Tax sharing agreement — 1 — 3 Other (1) 3 17 — 10 Total $ 63 $ 40 $ 54 $ 18 __________________________________________ (1) At September 30, 2016 and December 31, 2015 , approximately $14 million and $10 million , respectively, of the accounts payable, affiliates balance is comprised of reimbursable employee benefits paid by a Dynegy subsidiary on behalf of Genco. The following table presents the impact of related party transactions on our unaudited consolidated statements of operations for the three and nine months ended September 30, 2016 and 2015 . It is based primarily on the agreements discussed below and in Note 11 — Related Party Transactions of the Form 10-K. Three Months Ended September 30, Nine Months Ended September 30, (amounts in millions) Income Statement Line Item 2016 2015 2016 2015 Power supply agreements Revenues $ 147 $ 146 $ 343 $ 418 Services agreement Operating and maintenance expense $ 7 $ 7 $ 23 $ 26

Pension and Other Post-Employ28

Pension and Other Post-Employment Benefits (Tables)	9 Months Ended
	Sep. 30, 2016
Postemployment Benefits [Abstract]
Schedule of Net Periodic Benefit Costs	The following table presents the components of our net periodic benefit cost (gain) of the EEI pension and other post-employment benefit plans for the three and nine months ended September 30, 2016 and 2015 . Also reflected is an allocation of net periodic benefit cost (gain) from our participation in Dynegy’s single-employer pension and other post-employment plans for the three and nine months ended September 30, 2016 and 2015 . Pension Benefits Other Benefits Three Months Ended September 30, (amounts in millions) 2016 2015 2016 2015 Service cost $ — $ 1 $ — $ — Interest cost — — — 1 Expected return on plan assets (1 ) (1 ) — (1 ) Amortization of: Prior service credit 1 1 (1 ) (1 ) Net periodic benefit cost (gain) $ — $ 1 $ (1 ) $ (1 ) Pension Benefits Other Benefits Nine Months Ended September 30, (amounts in millions) 2016 2015 2016 2015 Service cost $ 2 $ 2 $ — $ 1 Interest cost 2 2 1 2 Expected return on plan assets (3 ) (3 ) (2 ) (3 ) Amortization of: Prior service credit 1 1 (2 ) (1 ) Net periodic benefit cost (gain) $ 2 $ 2 $ (3 ) $ (1 )

Basis of Presentation and Org29

Basis of Presentation and Organization (Details) - USD ($)		Oct. 14, 2016	Sep. 30, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Long-term debt, gross			$ 825,000,000	$ 825,000,000
Electric Energy, Inc
Schedule of Equity Method Investments [Line Items]
Ownership percentage			80.00%
Illinois Power Generating Company
Schedule of Equity Method Investments [Line Items]
Long-term debt, gross			$ 825,000,000
Unsecured Debt | 7.00% Senior Notes Series H, due 2018
Schedule of Equity Method Investments [Line Items]
Face amount	[1]		$ 300,000,000	$ 300,000,000
Restructuring Support Agreement | Genco And Ad Hock Group Of Shareholders | Affiliated Entity | Subsequent Event | Genco Senior Notes Series F, H, and I
Schedule of Equity Method Investments [Line Items]
Face amount		$ 825,000,000
Restructuring Support Agreement | Genco And Ad Hock Group Of Shareholders | Affiliated Entity | Subsequent Event | Unsecured Debt
Schedule of Equity Method Investments [Line Items]
Face amount		$ 210,000,000
[1]	On October 14, 2016, we entered into the RSA with Dynegy and the Ad Hoc Group to restructure our Senior Notes. On November 7, 2016, we launched the Restructuring in accordance with the terms of the RSA. See Note 13—Subsequent Events—Genco Debt Restructure for further discussion.

Accounting Policies (Details)

Accounting Policies (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Accounting Policies [Abstract]
Restricted cash	$ 6	$ 0	$ 6
Prepayments and Other Current Assets | Accounting Standards Update 2015-03
Debt Instrument [Line Items]
Deferred Finance Costs, Net		1
Other Noncurrent Assets | Accounting Standards Update 2015-03
Debt Instrument [Line Items]
Deferred Finance Costs, Net		$ 3

Risk Management, Derivatives 31

Risk Management, Derivatives and Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Derivative [Line Items]
Loss on interest rate swap expected to be written off	$ 3		$ 3
Not Designated as Hedging Instrument
Derivative [Line Items]
Market-to-market gains (losses)	0	$ 0	0	$ 0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Interest Rate Swap
Derivative [Line Items]
Pretax losses on interest rate derivatives	$ 3		$ 3		$ 4
Amortization period of deferred losses			10 years

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized discount and debt issuance costs	[1]	$ 4	$ 5
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized discount and debt issuance costs		$ 4	5
Unsecured Debt | 7.00% Senior Notes Series H, due 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated rate		7.00%
Unsecured Debt | 7.00% Senior Notes Series H, due 2018 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (300)	(299)
Unsecured Debt | 7.00% Senior Notes Series H, due 2018 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (119)	(204)
Unsecured Debt | 6.30% Senior Notes Series I, due 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated rate		6.30%
Unsecured Debt | 6.30% Senior Notes Series I, due 2020 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (249)	(249)
Unsecured Debt | 6.30% Senior Notes Series I, due 2020 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (99)	(148)
Unsecured Debt | 7.95% Senior Notes Series F, due 2032
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated rate		7.95%
Unsecured Debt | 7.95% Senior Notes Series F, due 2032 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (272)	(272)
Unsecured Debt | 7.95% Senior Notes Series F, due 2032 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	[2]	$ (107)	$ (162)
[1]	Includes $4 million related to the reclassification of unamortized debt issuance costs as of December 31, 2015. Please read Note 2—Accounting Policies for further discussion.
[2]	Combined carrying amounts include unamortized discounts and debt issuance costs of $4 million and $5 million as of September 30, 2016 and December 31, 2015, respectively. Please read Note 8—Debt for further discussion.

Accumulated Other Comprehensi33

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning of year			$ (10)		$ (16)
Actuarial gain due to pension plan remeasurement (net of tax benefit of zero and $5, respectively)			0		5
Reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges (net of tax of zero and zero, respectively)	$ 0	$ 1	1	[1]	1	[1]
Amortization of unrecognized prior service credit (net of tax of zero and zero, respectively)	0	0	(1)	[2]	0	[2]
Net current period other comprehensive income (loss), net of tax			0		6
End of period	(10)	(10)	(10)		(10)
Tax on actuarial loss due to pension plan remeasurement	0	5	0		5
Tax of reclassification of mark-to-market losses to earnings on interest rate swaps designated as cash flow hedges, net	$ 0	$ 0	0		0
Tax expense of amortization of unrecognized prior service credit and actuarial loss			$ 0		$ 0
[1]	Amount related to the reclassification of mark-to-market losses on cash flow hedging activities and was recorded in Interest expense on our unaudited consolidated statements of operations. Please read Note 3—Risk Management, Derivatives and Financial Instruments for further discussion.
[2]	Amounts are associated with our defined benefit pension and other post-employment benefit plans and are included in the computation of net periodic benefit cost (gain). Please read Note 12—Pension and Other Post-Employment Benefits.

Inventory (Details)

Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Materials and supplies	$ 30	$ 30
Coal	65	102
Fuel oil	1	1
Total	$ 96	$ 133

Property, Plant and Equipment35

Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 583	$ 1,750
Accumulated depreciation	(376)	(813)
Property, plant and equipment, net	207	937
Power generation
Property, Plant and Equipment [Line Items]
Property, plant and equipment	510	1,511
Building and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	51	212
Office and other equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 22	$ 27

Property, Plant and Equipment36

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Asset Impairment Charges		$ 855	$ 667	$ 855
Impairment of long-lived assets	$ 69	$ 855	736	$ 855
Newton Facility
Property, Plant and Equipment [Line Items]
Fair value of assets, Newton Facility	71		71
Newton Facility | Other Capitalized Property Plant and Equipment
Property, Plant and Equipment [Line Items]
Asset Impairment Charges	$ 69		$ 0
Discount rate	13.00%
Growth rate	2.50%

Debt (Details)

Debt (Details) - USD ($)		9 Months Ended
		Sep. 30, 2016	Oct. 14, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt, gross		$ 825,000,000		$ 825,000,000
Unamortized discount and debt issuance costs	[1]	(4,000,000)		(5,000,000)
Total Long-term debt	[2]	$ 821,000,000		820,000,000
Genco restricted payment interest coverage ratio minimum	[3]	1.75%
Genco additional indebtedness interest coverage ratio minimum	[4]	2.50%
Genco additional indebtedness debt-to-capital ratio maximum	[4]	60.00%
Dividend restrictions, interest coverage ratio determination period		1 year
Dividend restrictions, projected interest coverage ratio determination period		2 years
Unsecured Debt | 7.00% Senior Notes Series H, due 2018
Debt Instrument [Line Items]
Face amount	[5]	$ 300,000,000		300,000,000
Stated rate		7.00%
Unsecured Debt | 6.30% Senior Notes Series I, due 2020
Debt Instrument [Line Items]
Face amount	[5]	$ 250,000,000		250,000,000
Stated rate		6.30%
Unsecured Debt | 7.95% Senior Notes Series F, due 2032
Debt Instrument [Line Items]
Face amount	[5]	$ 275,000,000		275,000,000
Stated rate		7.95%
Accounting Standards Update 2015-03
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs				$ (4,000,000)
Subsequent Event | Restructuring Support Agreement | Affiliated Entity | Genco And Ad Hock Group Of Shareholders | Genco Senior Notes Series F, H, and I
Debt Instrument [Line Items]
Face amount			$ 825,000,000
Subsequent Event | Restructuring Support Agreement | Affiliated Entity | Genco And Ad Hock Group Of Shareholders | Unsecured Debt
Debt Instrument [Line Items]
Face amount			$ 210,000,000
[1]	Includes $4 million related to the reclassification of unamortized debt issuance costs as of December 31, 2015. Please read Note 2—Accounting Policies for further discussion.
[2]	Our Senior Notes are non-recourse to Dynegy.
[3]	As of the date of a restricted payment, as defined, the minimum ratio must have been achieved for the most recently ended four fiscal quarters and projected by management to be achieved for each of the subsequent four six-month periods.
[4]	Ratios must be computed on a pro forma basis considering the additional indebtedness to be incurred and the related interest expense. Other borrowings from external, third-party sources are included in the definition of indebtedness and are subject to these incurrence tests.
[5]	On October 14, 2016, we entered into the RSA with Dynegy and the Ad Hoc Group to restructure our Senior Notes. On November 7, 2016, we launched the Restructuring in accordance with the terms of the RSA. See Note 13—Subsequent Events—Genco Debt Restructure for further discussion.

Commitments and Contingencies (

Commitments and Contingencies (Details)	9 Months Ended
	Sep. 30, 2016$ / MWh	May 31, 2015complaint
Long-term Purchase Commitment [Line Items]
Environmental remediation obligations, permitting matters, statute of limitations	5 years
MISO 2015-2016 Planning Resource Auction
Long-term Purchase Commitment [Line Items]
Number of complaints | complaint		3
Loss Contingency, Actions Taken by FERC, 2016 and 2017 Planning Reserve Auction, Initial Reference Level for Capacity Per Day | $ / MWh	0

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Accounts receivable, affiliates		$ 63		$ 63		$ 54
Accounts payable, affiliates		40		40		18
Power Supply Agreements | Revenues
Related Party Transaction [Line Items]
Revenues		147	$ 146	343	$ 418
Services Agreement | Operating and Maintenance Expense
Related Party Transaction [Line Items]
Expenses		7	$ 7	23	$ 26
Collateral Agreement with IPM
Related Party Transaction [Line Items]
Collateral amount, if any		15		15
Collateral amount, additional demand		7.5		7.5
Collateral amount outstanding		0		0
Collateral Agreement with IPM | Maximum
Related Party Transaction [Line Items]
Collateral amount, if any		22.5		22.5
Power Supply Agreements
Related Party Transaction [Line Items]
Accounts receivable, affiliates		60		60		54
Accounts payable, affiliates		0		0		0
Service Agreement
Related Party Transaction [Line Items]
Accounts receivable, affiliates		0		0		0
Accounts payable, affiliates		22		22		5
Tax Sharing Agreement
Related Party Transaction [Line Items]
Accounts receivable, affiliates		0		0		0
Accounts payable, affiliates		1		1		3
Other Agreements
Related Party Transaction [Line Items]
Accounts receivable, affiliates	[1]	3		3		0
Accounts payable, affiliates	[1]	17		17		10
Other Agreements | Dynegy Subsidiary
Related Party Transaction [Line Items]
Accounts payable, affiliates		$ 14		$ 14		$ 10
[1]	At September 30, 2016 and December 31, 2015, approximately $14 million and $10 million, respectively, of the accounts payable, affiliates balance is comprised of reimbursable employee benefits paid by a Dynegy subsidiary on behalf of Genco

Income Taxes (Details)

Income Taxes (Details)	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	16.00%
Statutory tax rate	35.00%

Pension and Other Post-Employ41

Pension and Other Post-Employment Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net unamortized gain arising during the period		$ (13)
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 0	1	$ 2	$ 2
Interest cost	0	0	2	2
Expected return on plan assets	(1)	(1)	(3)	(3)
Amortization of: Prior service credit	1	1	1	1
Net periodic benefit cost (gain)	0	1	2	2
Other post-employment Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0	0	0	1
Interest cost	0	1	1	2
Expected return on plan assets	0	(1)	(2)	(3)
Amortization of: Prior service credit	(1)	(1)	(2)	(1)
Net periodic benefit cost (gain)	$ (1)	$ (1)	$ (3)	$ (1)

Subsequent Event (Details)

Subsequent Event (Details) - Affiliated Entity - Genco And Ad Hock Group Of Shareholders - Subsequent Event - USD ($) $ / shares in Units, shares in Millions	Oct. 14, 2016	Oct. 24, 2016
Subsequent Event [Line Items]
Payments of debt restructuring costs	$ 130,000,000
Restructuring Support Agreement
Subsequent Event [Line Items]
Payments of debt restructuring costs	9,000,000
Return of capital	$ 61,000,000
Warrants	10
Term of warrants (in years)	7 years
Exercise price of warrants (in dollars per warrant)	$ 35
Aggregate percent of principal holders, participation percentage	97.00%
Aggregate percent of principal holders acceptance for prepackaged Chapter 11	66.70%
Related party participation, percent		70.00%
Genco Senior Notes Series F, H, and I | Restructuring Support Agreement
Subsequent Event [Line Items]
Face amount	$ 825,000,000
Unsecured Debt | Restructuring Support Agreement
Subsequent Event [Line Items]
Face amount	$ 210,000,000