Vistra (VST) 10-Q 4 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Vistra Energy Corp.
Entity Central Index Key	1,692,819
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		522,955,994

Condensed Statements Of Consoli

Condensed Statements Of Consolidated Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Operating revenues	$ 765	$ 1,357
Fuel, purchased power costs and delivery fees	(650)	(683)
Operating costs	(194)	(214)
Depreciation and amortization	(153)	(170)
Selling, general and administrative expenses	(162)	(135)
Operating income (loss)	(394)	155
Other income	10	9
Other deductions	(2)	0
Interest expense and related charges	9	(24)
Impacts of tax receivable agreement	(18)	(21)
Income (loss) before income taxes	(395)	119
Income tax (expense) benefit	89	(41)
Net income (loss)	$ (306)	$ 78
Weighted average shares of common stock outstanding:
Weighted average shares of common stock outstanding - basic	428,450,384	427,583,339
Weighted average shares of common stock outstanding - diluted	428,450,384	427,800,350
Net income per weighted average share of common stock outstanding:
Net income per weighted average share of common stock outstanding - basic	$ (0.71)	$ 0.18
Net income per weighted average share of common stock outstanding - diluted	$ (0.71)	$ 0.18

Condensed Statements Of Consol3

Condensed Statements Of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (306)	$ 78
Other comprehensive income (loss), net of tax effects:
Effects related to pension and other retirement benefit obligations (net of tax benefit of $— in all periods)	1	0
Total other comprehensive income	1	0
Comprehensive income (loss)	$ (305)	$ 78

Condensed Statements Of Consol4

Condensed Statements Of Consolidated Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Effects related to pension and other retirement benefit obligations (net of tax benefit of $— in all periods)	$ 0	$ 0

Condensed Statements Of Consol5

Condensed Statements Of Consolidated Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows — operating activities:
Net income (loss)	$ (306)	$ 78
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation and amortization	180	226
Deferred income tax (benefit) expense, net	(83)	42
Unrealized net (gain) loss from mark-to-market valuations of derivatives	356	(129)
Accretion expense	19	14
Impacts of Tax Receivable Agreement	18	21
Stock-based compensation	6	4
Other, net	7	(13)
Changes in operating assets and liabilities:
Margin deposits, net	(64)	113
Accrued interest	(11)	(31)
Accrued taxes	(69)	(73)
Accrued incentive plan	(50)	(73)
Other operating assets and liabilities	(25)	(38)
Cash (used in) provided by operating activities	(22)	141
Cash flows — financing activities:
Repayments/repurchases of debt	(10)	(13)
Other, net	1	(5)
Cash used in financing activities	(9)	(18)
Cash flows — investing activities:
Capital expenditures	(39)	(31)
Nuclear fuel purchases	(11)	(12)
Solar development expenditures	21	0
Proceeds from sales of nuclear decommissioning trust fund securities	46	79
Investments in nuclear decommissioning trust fund securities	(51)	(84)
Other, net	(1)	(3)
Cash used in investing activities	(77)	(51)
Net change in cash, cash equivalents and restricted cash	(108)	72
Cash, cash equivalents and restricted cash — beginning balance	2,046	1,588
Cash, cash equivalents and restricted cash — ending balance	$ 1,938	$ 1,660

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,379	$ 1,487
Restricted cash	59	59
Trade accounts receivable — net	463	582
Inventories	226	253
Commodity and other derivative contractual assets	404	190
Margin deposits related to commodity contracts	93	30
Prepaid expense and other current assets	75	72
Total current assets	2,699	2,673
Restricted cash	500	500
Investments	1,232	1,240
Property, plant and equipment — net	4,850	4,820
Goodwill	1,907	1,907
Identifiable intangible assets — net	2,437	2,530
Commodity and other derivative contractual assets	169	58
Accumulated deferred income taxes	793	710
Other noncurrent assets	189	162
Total assets	14,776	14,600
Current liabilities:
Long-term debt due currently	44	44
Trade accounts payable	421	473
Commodity and other derivative contractual liabilities	595	224
Margin deposits related to commodity contracts	3	4
Accrued taxes	58	58
Accrued taxes other than income	59	136
Accrued interest	3	16
Asset retirement obligations	126	99
Other current liabilities	248	297
Total current liabilities	1,557	1,351
Long-term debt, less amounts due currently	4,366	4,379
Commodity and other derivative contractual liabilities	386	102
Noncurrent TRA obligation at the end of the period	351	333
Asset retirement obligation	1,817	1,837
Other noncurrent liabilities and deferred credits	239	256
Total liabilities	8,716	8,258
Commitments and Contingencies
Total equity:
Common stock (par value — $0.01; number of shares authorized — 1,800,000,000) (shares outstanding: March 31, 2018 — 428,506,325; December 31, 2017 — 428,398,802)	4	4
Additional paid-in-capital	7,772	7,765
Retained deficit	(1,700)	(1,410)
Accumulated other comprehensive income	(16)	(17)
Total equity	6,060	6,342
Total liabilities and equity	$ 14,776	$ 14,600

Condensed Consolidated Balance7

Condensed Consolidated Balance Sheets Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Statement of Changes in Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.01
Common stock, shares authorized	1,800,000,000		1,800,000,000
Common stock, shares outstanding	428,506,325	428,398,802	427,587,401	427,580,232

Business And Significant Accoun

Business And Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Business And Significant Accounting Policies	BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES Description of Business References in this report to "we," "our," "us" and "the Company" are to Vistra Energy and/or its subsidiaries, as apparent in the context. See Glossary for defined terms. Vistra Energy is a holding company operating an integrated power business in Texas. Through our Luminant and TXU Energy subsidiaries, we are engaged in competitive electricity market activities including power generation, wholesale energy sales and purchases, commodity risk management and retail sales of electricity to end users. Vistra Energy has three reportable segments: (i) our Wholesale Generation segment, consisting largely of Luminant; (ii) our Retail Electricity segment, consisting largely of TXU Energy, and (iii) our Asset Closure segment, consisting of financial results associated with retired plants and mines. The Asset Closure segment was established as of January 1, 2018, and we have recast information from prior periods to reflect this change in reportable segments. See Note 16 for further information concerning reportable business segments. Merger Transaction On the Merger Date, Vistra Energy and Dynegy completed the transactions contemplated by the Merger Agreement entered into in October 2017. Pursuant to the Merger Agreement, Dynegy merged with and into Vistra Energy, with Vistra Energy continuing as the surviving corporation. Because the Merger occurred after March 31, 2018, Vistra Energy's condensed consolidated financial statements and the notes related thereto do not include the financial condition or the operating results of Dynegy in any of the periods presented herein or otherwise take into account the closing of the Merger or the effects of the Merger or any transactions related thereto. See Note 2 for a summary of the Merger and related transactions. Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and on the same basis as the audited financial statements included in our 2017 Form 10-K, with the exception of the change in reporting segments as detailed above. Adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the results of operations and financial position have been included therein. All intercompany items and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been omitted pursuant to the rules and regulations of the SEC. Because the condensed consolidated interim financial statements do not include all of the information and footnotes required by U.S. GAAP, they should be read in conjunction with the audited financial statements and related notes contained in our 2017 Form 10-K. The results of operations for an interim period may not give a true indication of results for a full year. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated. Use of Estimates Preparation of financial statements requires estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements, estimates of expected obligations, judgment related to the potential timing of events and other estimates. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information. Adoption of New Accounting Standards Revenue from Contracts with Customers — On January 1, 2018, we adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606) and all related amendments (new revenue standard) using the modified retrospective method for all contracts outstanding at the time of adoption. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new revenue standard to be immaterial to our net income on an ongoing basis and our retail electricity and wholesale generation revenues will continue to be recognized when electricity and other services are delivered to our customers. The impact of adopting the new revenue standard primarily relates to the deferral of acquisition costs associated with retail contracts with customers that were previously expensed as incurred. Under the new revenue standard, these amounts will be capitalized and amortized over the expected life of the customer. As of January 1, 2018, the cumulative effect of the changes made to our condensed consolidated balance sheet for the adoption of the new revenue standard was as follows: December 31, 2017 Adoption of New Revenue Standard January 1, 2018 Impact on condensed consolidated balance sheet: Assets Prepaid expense and other current assets $ 72 $ 5 $ 77 Accumulated deferred income taxes $ 710 $ (4 ) $ 706 Other noncurrent assets $ 162 $ 16 $ 178 Equity Retained deficit $ (1,410 ) $ 17 $ (1,393 ) In accordance with the new revenue standard requirements, the disclosure of the impact of adoption on our condensed statement of consolidated income (loss) and condensed consolidated balance sheet was as follows: Three Months Ended March 31, 2018 As Reported Amount Without Adoption of New Revenue Standard Effect of Change Higher (Lower) Impact on condensed statement of consolidated income (loss): Operating revenues $ 765 $ 764 $ 1 Selling, general and administrative expenses $ (162 ) $ (165 ) $ 3 Net income (loss) (306 ) (309 ) 3 March 31, 2018 As Reported Balances Without Adoption of New Revenue Standard Effect of Change Higher (Lower) Impact on condensed consolidated balance sheet: Assets Prepaid expense and other current assets $ 75 $ 69 $ 6 Accumulated deferred income taxes $ 793 $ 797 $ (4 ) Other noncurrent assets $ 189 $ 169 $ 20 Equity Retained deficit $ (1,700 ) $ (1,720 ) $ 20 See Note 5 for the disclosures required by the new revenue standard. Statement of Cash Flows — In November 2016, the FASB issued ASU 2016-18 Statement of Cash Flows (Topic 230): Restricted Cash . The ASU requires restricted cash to be included in the cash and cash equivalents and a reconciliation between the change in cash and cash equivalents and the amounts presented on the balance sheet (see Note 17 ). We adopted the standard on January 1, 2018. The ASU modified our presentation of our condensed statements of consolidated cash flows, and retrospective application to comparative periods presented was required. For the three months ended March 31, 2017 , our condensed statement of consolidated cash flows previously reflected a source of cash of $1 million reported as changes in restricted cash that is now reported in net change in cash, cash equivalents and restricted cash. See the condensed statements of consolidated cash flows and Note 17 for disclosures related to the adoption of this accounting standard. Changes in Accounting Standards In February 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-02 (ASU 2016-02), Leases . The ASU amends previous GAAP to require the recognition of lease assets and liabilities for operating leases. The ASU will be effective for fiscal years beginning after December 15, 2018, including interim periods within those years. Retrospective application to comparative periods presented will be required in the year of adoption. We are currently evaluating the impact of this ASU on our financial statements.

Merger Transaction (Notes)

Merger Transaction (Notes)	3 Months Ended
	Mar. 31, 2018
Merger Transaction [Abstract]
Merger Transaction [Text Block]	MERGER TRANSACTION Merger Summary On the Merger Date, Vistra Energy and Dynegy completed the transactions contemplated by the Merger Agreement entered into in October 2017. Pursuant to the Merger Agreement, Dynegy merged with and into Vistra Energy, with Vistra Energy continuing as the surviving corporation. The Merger is intended to qualify as a tax-free reorganization under the Internal Revenue Code, as amended, so that none of Vistra Energy, Dynegy or any of the Dynegy stockholders will recognize any gain or loss in the transaction, except that Dynegy stockholders could recognize a gain or loss with respect to cash received in lieu of fractional shares of Vistra Energy's common stock. Vistra Energy is the acquirer for both federal tax and accounting purposes. At the closing of the Merger, each issued and outstanding share of Dynegy common stock, par value $0.01 per share, other than shares owned by Vistra Energy or its subsidiaries, held in treasury by Dynegy or held by a subsidiary of Dynegy, was automatically converted into 0.652 shares of common stock, par value $0.01 per share, of Vistra Energy (the Exchange Ratio), except that cash was paid in lieu of fractional shares, which resulted in Vistra Energy issuing 94,409,573 shares of Vistra Energy common stock to the former Dynegy stockholders. The total number of Vistra Energy shares outstanding at the close of the Merger was 522,932,453 shares. Dynegy stock options and equity-based awards outstanding immediately prior to the Effective Time were generally automatically converted upon completion of the Merger into stock options and equity-based awards, respectively, with respect to Vistra Energy's common stock, after giving effect to the Exchange Ratio. Following is a list of events that took place in connection with the completion of the Merger. Warrants — The Company entered into an agreement whereby holders of each outstanding warrant previously issued by Dynegy will be entitled to receive, upon exercise, the equity securities to which the holder would have been entitled to receive of Dynegy common stock converted into shares of Vistra Energy common stock at the Exchange Ratio. As of the Merger Date, nine million warrants expiring in 2024 with an exercise price of $35.00 were outstanding, each of which can be redeemed for 0.652 share of Vistra Energy common stock. Credit Agreement — The Company assumed the obligations under Dynegy's $3.563 billion credit agreement consisting of a $2.018 billion senior secured term loan facility due 2024 and a $1.545 billion senior secured revolving credit facility. As of the Merger Date, there were no cash borrowings and $656 million of letters of credit outstanding under the senior secured revolving credit facility. On April 23, 2018, $70 million of the senior secured revolving credit facility matured. Senior Notes — The Company and certain of the Company's wholly-owned subsidiaries that guarantee obligations under the Dynegy credit agreement assumed the following obligations of Dynegy: • $850 million of outstanding 6.75% Senior Notes due 2019, which were redeemed on May 1, 2018 at a redemption price of 101.688% , plus accrued and unpaid interest to but not including the date of redemption; • $1.750 billion of 7.375% Senior Notes due 2022; • $500 million of 5.875% Senior Notes due 2023; • $1.250 billion of 7.625% Senior Notes due 2024; • $188 million of 8.034% Senior Notes due 2024; • $750 million of 8.000% Senior Notes due 2025, and • $850 million of 8.125% Senior Notes due 2026. Tangible Equity Units — The Company assumed the obligations of Dynegy's 4,600,000 7.00% tangible equity units, each with a stated amount of $100.00 and each comprised of (i) a prepaid stock purchase contract that will deliver to the holder, not later than July 1, 2019, unless earlier redeemed or settled, not more than 4.0421 shares of Vistra Energy common stock and not less than 3.2731 shares of Vistra Energy common stock per contract based upon the applicable fixed settlement rate in the contract and (ii) a senior amortizing note with an outstanding principal amount of $45 million that pays an equal quarterly cash installment of $1.7500 per am ortizing note. In the aggregate, the annual quarterly cash installments will be equivalent to a 7.00% cash payment per year with respect to each $100.00 stated amount of tangible equity units. Business Combination The Merger is anticipated to provide a number of significant potential strategic benefits and opportunities to Vistra Energy, including increased scale and market diversification, rebalanced asset portfolio and improved earnings and cash flow. The Merger is being accounted for in accordance with ASC 805, Business Combinations (ASC 805), with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the Merger Date. Due to the limited time between the Merger Date and this filing, our purchase price allocation for the assets acquired and the liabilities assumed in the Merger has not been completed. The results of operations of Dynegy will be reported in our consolidated financial statements beginning as of the Merger Date. Based on the opening price of Vistra Energy common stock on the Merger Date, the preliminary purchase price was approximately $2.3 billion . Our initial accounting of the purchase price allocation for the assets acquired and the liabilities assumed in the Merger and the supplemental pro forma financial results is currently underway and will be presented no later than the second quarter of 2018.

Acquisition and Development of

Acquisition and Development of Generation Facilities (Notes)	3 Months Ended
	Mar. 31, 2018
Acquisition And Development Of Generation Facilities [Abstract]
Business Combination Disclosure [Text Block]	ACQUISITION AND DEVELOPMENT OF GENERATION FACILITIES Odessa Acquisition In August 2017, La Frontera Holdings, LLC (La Frontera), an indirect wholly owned subsidiary of Vistra Energy, purchased a 1,054 MW CCGT natural gas fueled generation plant (and other related assets and liabilities) located in Odessa, Texas (Odessa Facility) from Odessa-Ector Power Partners, L.P., an indirect wholly owned subsidiary of Koch Ag & Energy Solutions, LLC (Koch) (altogether, the Odessa Acquisition). La Frontera paid an aggregate purchase price of approximately $355 million , plus a five -year earn-out provision, to acquire the Odessa Facility. The purchase price was funded by cash on hand. The Odessa Acquisition was accounted for as an asset acquisition. Substantially all of the approximately $355 million purchase price was assigned to property, plant and equipment in our consolidated balance sheet. Additionally, the initial fair value associated with an earn-out provision of approximately $16 million was included as consideration in the overall purchase price. The earn-out provision requires cash payments to be made to Koch if spark-spreads related to the pricing point of the Odessa Facility exceed certain thresholds. Subsequent to the acquisition, the earn-out provision has been accounted for as a derivative in our consolidated financial statements, and a partial buyback of the earn-out provision was settled in February 2018. Upton Solar Development In May 2017, we acquired the rights to develop, construct and operate a utility scale solar photovoltaic power generation facility in Upton County, Texas (Upton). As part of this project, we entered a turnkey engineering, procurement and construction agreement to construct the approximately 180 MW facility. For the three months ended March 31, 2018 , we have spent approximately $21 million related to this project primarily for progress payments under the engineering, procurement and construction agreement. The facility began test operations in March 2018 and is expected to begin commercial operations in May 2018.

Retirement of Generation Facil

Retirement of Generation Facilities (Notes)	3 Months Ended
	Mar. 31, 2018
Retirement of Generation Facilities [Abstract]
Retirement of generation facilities	RETIREMENT OF GENERATION FACILITIES In January and February 2018, we retired three power plants with a total installed nameplate generation capacity of 4,167 MW. Luminant decided to retire these units because they were projected to be uneconomic based on current market conditions and would have faced significant environmental costs associated with operating such units. In the case of the Sandow units, the decision also reflected the execution of a contract termination agreement pursuant to which the Company and Alcoa agreed to an early settlement of a long-standing power and mining agreement. The following table details the units retired. Name Location (all in the state of Texas) Fuel Type Installed Nameplate Generation Capacity (MW) Number of Units Date Units Taken Offline Monticello Titus County Lignite/Coal 1,880 3 January 4, 2018 Sandow Milam County Lignite 1,137 2 January 11, 2018 Big Brown Freestone County Lignite/Coal 1,150 2 February 12, 2018 Total 4,167 7

Revenue (Notes)

Revenue (Notes)	3 Months Ended
	Mar. 31, 2018
Revenue Recognition and Deferred Revenue [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE The following table disaggregates our revenue by major source: Three Months Ended March 31, 2018 Retail Electricity Wholesale Generation Asset Closure Eliminations Consolidated Revenue from contracts with customers: Revenue from Oncor service area $ 662 $ — $ — $ — $ 662 Revenue from other TDSP service areas 287 — — — 287 Wholesale generation revenue from ERCOT — 174 36 — 210 Revenue from non-affiliated REPs — 19 — — 19 Revenue from other wholesale contracts — 34 — — 34 Total revenue from contracts with customers 949 227 36 — 1,212 Other revenues: Retail contract amortization (12 ) — — — (12 ) Hedging and other revenues 35 (462 ) (8 ) — (435 ) Affiliate sales — (298 ) — 298 — Total other revenues 23 (760 ) (8 ) 298 (447 ) Total revenues $ 972 $ (533 ) $ 28 $ 298 $ 765 Energy Charges Revenue is recognized when electricity is delivered to our customers in an amount that we expect to invoice for volumes delivered or services provided. Sales tax is excluded from revenue. Residential invoices are due within 20 days from invoice date and business customer payment terms vary from 15 to 45 days from invoice date. Revenue is recognized over-time using the output method based on kilowatt hours delivered. Energy charges are delivered as a series of distinct services and are accounted for as a single performance obligation. Wholesale Generation Revenue from ERCOT Revenue is recognized when volumes are delivered to ERCOT. Cash settlement occurs within 10 business days after delivery. Revenue is recognized over-time using the output method based on kilowatt hours delivered. Luminant operates as a market participant within ERCOT and expects to continue to remain in a contract agreement with ERCOT indefinitely. Wholesale generation revenues are delivered as a series of distinct services and are accounted for as a single performance obligation. Revenue from Nonaffiliated Retail Electric Providers Revenue is recognized when volumes are delivered to the non-affiliated retail electric provider. Cash settlement occurs within 20 days following the month of delivery. Revenue is recognized over-time using the output method based on kilowatt hours delivered. Revenue from non-affiliated retail electric providers are delivered as a series of distinct services and are accounted for as a single performance obligation. Revenue from Other Wholesale Contracts Other wholesale contracts include other revenue activity with ERCOT, such as ancillary services, auction revenue and ERCOT neutrality revenue. Revenue is recognized when the service is performed. Cash settlement occurs within 10 business days after invoicing. Revenue is recognized over-time using the output method based on kilowatt hours delivered or other applicable measurements. Luminant operates as a market participant within ERCOT and expects to continue to remain in a contract agreement with ERCOT indefinitely. Other wholesale contracts are delivered as a series of distinct services and are accounted for as a single performance obligation. Contract and Other Customer Acquisition Costs We defer costs to acquire residential and business retail contracts and amortize these costs over the expected life of the contract. The expected life of a retail contract is calculated using historical attrition rates, which we believe to be an accurate indicator of future attrition rates. The deferred acquisition and contract cost balance as of March 31, 2018 and January 1, 2018 was $27 million and $22 million , respectively. The amortization expense related to these costs during the three months ended March 31, 2018 totaled $3 million and was recorded as selling, general and administrative expenses and $1 million was recorded to operating costs in the condensed statement of consolidated income (loss). Practical Expedients The vast majority of revenues are recognized under the right to invoice practical expedient, which allows us to recognize revenue in the same amount that we invoice our customers. We do not disclose the value of unsatisfied performance obligations for contracts for which we recognize revenue using the right to invoice practical expedient. We use the portfolio approach to categorize similar customer contracts into single performance obligations. Sales taxes are not included in revenue. Accounts Receivable The following table presents trade accounts receivable relating to both contracts with customers and other activities: March 31, 2018 Trade accounts receivable from contracts with customers — net $ 415 Other trade accounts receivable — net 48 Total trade accounts receivable — net $ 463

Goodwill and Identifiable Intan

Goodwill and Identifiable Intangible Assets (Notes)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Identifiable Intangible Assets	GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS Goodwill The carrying value of goodwill totaled $1.907 billion at both March 31, 2018 and December 31, 2017 . The goodwill arose in connection with our application of fresh start reporting at Emergence and was allocated entirely to the Retail Electricity reporting unit (see Note 1 ). Of the goodwill recorded at Emergence, $1.686 billion is deductible for tax purposes over 15 years on a straight-line basis. Identifiable Intangible Assets Identifiable intangible assets are comprised of the following: March 31, 2018 December 31, 2017 Identifiable Intangible Asset Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Retail customer relationship $ 1,648 $ 645 $ 1,003 $ 1,648 $ 572 $ 1,076 Software and other technology-related assets 186 57 129 183 47 136 Retail and wholesale contracts 154 99 55 154 87 67 Other identifiable intangible assets (a) 33 11 22 33 11 22 Total identifiable intangible assets subject to amortization $ 2,021 $ 812 1,209 $ 2,018 $ 717 1,301 Retail trade names (not subject to amortization) 1,225 1,225 Mineral interests (not currently subject to amortization) 3 4 Total identifiable intangible assets $ 2,437 $ 2,530 ____________ (a) Includes mining development costs and environmental allowances and credits. Amortization expense related to finite-lived identifiable intangible assets (including the classification in the condensed statements of consolidated income (loss)) consisted of: Identifiable Intangible Asset Condensed Statements of Consolidated Income (Loss) Line Three Months Ended March 31, 2018 2017 Retail customer relationship Depreciation and amortization $ 73 $ 105 Software and other technology-related assets Depreciation and amortization 10 8 Retail and wholesale contracts Operating revenues/fuel, purchased power costs and delivery fees 12 28 Other identifiable intangible assets Operating revenues/fuel, purchased power costs and delivery fees/depreciation and amortization 2 4 Total amortization expense (a) $ 97 $ 145 ____________ (a) Amounts recorded in depreciation and amortization totaled $85 million and $115 million for the three months ended March 31, 2018 and 2017 , respectively. Estimated Amortization of Identifiable Intangible Assets As of March 31, 2018 , the estimated aggregate amortization expense of identifiable intangible assets for each of the next five fiscal years is as shown below. Year Estimated Amortization Expense 2018 $ 368 2019 $ 268 2020 $ 192 2021 $ 142 2022 $ 89

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The calculation of our effective tax rate is as follows: Three Months Ended March 31, 2018 2017 Income (loss) before income taxes $ (395 ) $ 119 Income tax benefit (expense) $ 89 $ (41 ) Effective tax rate 22.5 % 34.5 % For the three months ended March 31, 2018 , the effective tax rate of 22.5% related to our income tax expense was higher than the U.S. Federal statutory rate of 21% due primarily to nondeductible TRA accretion and the Texas margin tax, net of federal benefit, offset by the difference in the forecasted effective tax rate and the statutory tax rate applied to mark-to-market unrealized losses. For the three months ended March 31, 2017 , the effective tax rate of 34.5% related to our income tax expense was lower than the U.S. Federal statutory rate of 35% due primarily to the difference in the forecasted effective tax rate and the statutory tax rate applied to mark-to-market unrealized gains, offset by deductible TRA accretion and the Texas margin tax, net of federal benefit. Liability for Uncertain Tax Positions Vistra Energy and its subsidiaries file income tax returns in U.S. federal and state jurisdictions and are expected to be subject to examinations by the IRS and other taxing authorities. Vistra Energy has limited operational history and filed its first federal tax return in October 2017. Vistra Energy is not currently under audit for any period, and we had no uncertain tax positions at both March 31, 2018 and December 31, 2017 .

Tax Receivable Agreement Obliga

Tax Receivable Agreement Obligation (Notes)	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Tax Receivables Agreement Obligation	TAX RECEIVABLE AGREEMENT OBLIGATION On the Effective Date, Vistra Energy entered into a tax receivable agreement (the TRA) with a transfer agent on behalf of certain former first lien creditors of our predecessor. The TRA generally provides for the payment by us to holders of TRA Rights of 85% of the amount of cash savings, if any, in U.S. federal and state income tax that we realize in periods after Emergence as a result of (a) certain transactions consummated pursuant to the Plan of Reorganization (including the step-up in tax basis in our assets resulting from the PrefCo Preferred Stock Sale), (b) the tax basis of all assets acquired in connection with the acquisition of two CCGT natural gas fueled generation facilities in April 2016 and (c) tax benefits related to imputed interest deemed to be paid by us as a result of payments under the TRA, plus interest accruing from the due date of the applicable tax return. Pursuant to the TRA, we issued the TRA Rights for the benefit of the first lien secured creditors of TCEH entitled to receive such TRA Rights under the Plan of Reorganization. Such TRA Rights are subject to various transfer restrictions described in the TRA and are entitled to certain registration rights more fully described in the Registration Rights Agreement (see Note 15 ). The following table summarizes the changes to the TRA obligation, reported as other current liabilities and Tax Receivable Agreement obligation in our condensed consolidated balance sheets, for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 2017 TRA obligation at the beginning of the period $ 357 $ 596 Accretion expense 18 21 TRA obligation at the end of the period 375 617 Less amounts due currently (24 ) (16 ) Noncurrent TRA obligation at the end of the period $ 351 $ 601 As of March 31, 2018 , the estimated carrying value of the TRA obligation totaled $375 million , which represents the discounted amount of projected payments under the TRA. The projected payments are based on certain assumptions, including but not limited to (a) the federal corporate income tax rate of 21% and (b) estimates of our taxable income in the current and future years. Our taxable income takes into consideration the current federal tax code and reflects our current estimates of future results of the business. These assumptions are subject to change, and those changes could have a material impact on the carrying value of the TRA obligation. The aggregate amount of undiscounted payments under the TRA is estimated to be approximately $1.2 billion , with more than half of such amount expected to be attributable to the first 15 tax years following Emergence, and the final payment expected to be made approximately 40 years following Emergence (assuming that the TRA is not terminated earlier pursuant to its terms). The carrying value of the obligation is being accreted to the amount of the gross expected obligation using the effective interest method. Changes in the amount of this obligation resulting from changes to either the timing or amount of TRA payments are recognized in the period of change and measured using the discount rate inherent in the initial fair value of the obligation. During the three months ended March 31, 2018 and 2017 , the Impacts of Tax Receivable Agreement on the condensed statements of consolidated income (loss) totaled $18 million and $21 million , respectively, which represents accretion expense for the period.

Earnings Per Share (Notes)

Earnings Per Share (Notes)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings per share available to common shareholders are based on the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated using the treasury stock method and includes the effect of all potential issuances of common shares under stock-based incentive compensation arrangements. Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Net Loss Shares Per Share Amount Net Income Shares Per Share Amount Net income (loss) available for common stock — basic $ (306 ) 428,450,384 $ (0.71 ) $ 78 427,583,339 $ 0.18 Dilutive securities: Stock-based incentive compensation plan — — — — 217,011 — Net income (loss) available for common stock — diluted $ (306 ) 428,450,384 $ (0.71 ) $ 78 427,800,350 $ 0.18 For the three months ended March 31, 2018 and 2017 , stock-based incentive compensation plan awards totaling 2,863,872 and 602,403 shares, respectively, were excluded from the calculation of diluted earnings per share because the effect would have been antidilutive.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT Amounts in the table below represent the categories of long-term debt obligations incurred by the Company. March 31, December 31, Vistra Operations Credit Facilities (a) $ 4,313 $ 4,323 Mandatorily redeemable subsidiary preferred stock (b) 70 70 8.82% Building Financing due semiannually through February 11, 2022 (c) 27 30 Total long-term debt including amounts due currently 4,410 4,423 Less amounts due currently (44 ) (44 ) Total long-term debt less amounts due currently $ 4,366 $ 4,379 ____________ (a) At March 31, 2018 , borrowings under the Vistra Operations Credit Facilities in our condensed consolidated balance sheet include debt premiums of $19 million , debt discounts of $2 million and debt issuance costs of $6 million . At December 31, 2017 , borrowings under the Vistra Operations Credit Facilities in our condensed consolidated balance sheet include debt premiums of $21 million , debt discounts of $2 million and debt issuance costs of $7 million . (b) Shares of mandatorily redeemable preferred stock in PrefCo issued as part of the Spin-Off (see Note 1 ). This subsidiary preferred stock is accounted for as a debt instrument under relevant accounting guidance. (c) Obligation related to a corporate office space capital lease. This obligation will be funded by amounts held in an escrow account that is reflected in other noncurrent assets in our condensed consolidated balance sheets. Vistra Operations Credit Facilities — At March 31, 2018 , the Vistra Operations Credit Facilities consisted of up to $5.162 billion in senior secured, first lien revolving credit commitments and outstanding term loans, consisting of revolving credit commitments of up to $860 million , including a $715 million letter of credit sub-facility (Revolving Credit Facility), initial term loans totaling $2.814 billion (Initial Term Loan B Facility), incremental term loans totaling $988 million (Incremental Term Loan B Facility, and together with the Initial Term Loan B Facility, the Term Loan B Facility) and letter of credit term loans totaling $500 million (Term Loan C Facility). The Vistra Operations Credit Facilities and related available capacity at March 31, 2018 are presented below. March 31, 2018 Vistra Operations Credit Facilities Maturity Date Facility Limit Cash Borrowings Available Capacity Revolving Credit Facility (a) August 4, 2021 $ 860 $ — $ 584 Initial Term Loan B Facility (b) August 4, 2023 2,814 2,814 — Incremental Term Loan B Facility (b) December 14, 2023 988 988 — Term Loan C Facility (c) August 4, 2023 500 500 18 Total Vistra Operations Credit Facilities $ 5,162 $ 4,302 $ 602 ___________ (a) Facility to be used for general corporate purposes. Facility includes a $715 million letter of credit sub-facility, of which $276 million of letters of credit were outstanding at March 31, 2018 . (b) Cash borrowings under the Term Loan B Facility reflect required scheduled quarterly payment in annual amount equal to 1% of the original principal amount with the balance paid at maturity. Principal amounts paid cannot be reborrowed. (c) Facility used for issuing letters of credit for general corporate purposes. Borrowings under this facility were funded to collateral accounts that are reported as restricted cash in our condensed consolidated balance sheets. At March 31, 2018 , the restricted cash supported $482 million in letters of credit outstanding (see Note 17 ), leaving $18 million in available letter of credit capacity. In February 2018, certain pricing terms for the Vistra Operations Credit Facility were amended. We accounted for this transaction as a modification of debt. At March 31, 2018 , cash borrowings under the Revolving Credit Facility would bear interest based on applicable LIBOR rates, plus a fixed spread of 2.25% , and there were no outstanding borrowings. Letters of credit issued under the Revolving Credit Facility bear interest of 2.25% . Amounts borrowed under the Initial Term Loan B Facility and the Term Loan C Facility bear interest based on applicable LIBOR rates, subject to a 0.75% floor, plus a fixed spread of 2.50% . Amounts borrowed under the Incremental Term Loan B Facility bear interest based on applicable LIBOR rates plus a fixed spread of 2.25% . At March 31, 2018 , the weighted average interest rate before taking into consideration interest rate swaps on outstanding borrowings was 4.38% , 4.07% and 4.38% under the Initial Term Loan B Facility, the Incremental Term Loan B Facility and the Term Loan C Facility, respectively. The Vistra Operations Credit Facilities also provide for certain additional fees payable to the agents and lenders, as well as availability fees payable with respect to any unused portions of the available Vistra Operations Credit Facilities. Obligations under the Vistra Operations Credit Facilities are secured by a lien covering substantially all of Vistra Operations' (and its subsidiaries') consolidated assets, rights and properties, subject to certain exceptions set forth in the Vistra Operations Credit Facilities. The Vistra Operations Credit Facilities also permit certain hedging agreements to be secured on a pari-passu basis with the Vistra Operations Credit Facilities in the event those hedging agreements met certain criteria set forth in the Vistra Operations Credit Facilities. The Vistra Operations Credit Facilities provide for affirmative and negative covenants applicable to Vistra Operations (and its restricted subsidiaries), including affirmative covenants requiring it to provide financial and other information to the agents under the Vistra Operations Credit Facilities and to not change its lines of business, and negative covenants restricting Vistra Operations' (and its restricted subsidiaries') ability to incur additional indebtedness, make investments, dispose of assets, pay dividends, grant liens or take certain other actions, in each case except as permitted in the Vistra Operations Credit Facilities. Vistra Operations' ability to borrow under the Vistra Operations Credit Facilities is subject to the satisfaction of certain customary conditions precedent set forth therein. The Vistra Operations Credit Facilities provide for certain customary events of default, including events of default resulting from non-payment of principal, interest or fees when due, material breaches of representations and warranties, material breaches of covenants in the Vistra Operations Credit Facilities or ancillary loan documents, cross-defaults under other agreements or instruments and the entry of material judgments against Vistra Operations. Solely with respect to the Revolving Credit Facility, and solely during a compliance period (which, in general, is applicable when the aggregate revolving borrowings and issued revolving letters of credit (in excess of $100 million ) exceed 30% of the revolving commitments), the agreement includes a covenant that requires the consolidated first lien net leverage ratio, which is based on the ratio of net first lien debt compared to an EBITDA calculation defined under the terms of the facilities, not to exceed 4.25 to 1.00. Although the period ended March 31, 2018 was not a compliance period, we would have been in compliance with this financial covenant if it was required to be tested at such date. Upon the existence of an event of default, the Vistra Operations Credit Facilities provide that all principal, interest and other amounts due thereunder will become immediately due and payable, either automatically or at the election of specified lenders. Interest Rate Swaps — Effective January 2017, we entered into $3.0 billion notional amount of interest rate swaps to hedge a portion of our exposure to our variable rate debt. The interest rate swaps expire in July 2023 and effectively fix the interest rates between 4.38% and 4.50% on $3.0 billion of our variable rate debt. The interest rate swaps are secured by a first lien secured interest on a pari-passu basis with the Vistra Operations Credit Facilities.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES Guarantees We have entered into contracts that contain guarantees to unaffiliated parties that could require performance or payment under certain conditions. As of March 31, 2018 , there are no material outstanding claims related to our guarantee obligations, and we do not anticipate we will be required to make any material payments under these guarantees. Letters of Credit At March 31, 2018 , we had outstanding letters of credit under the Vistra Operations Credit Facilities totaling $758 million as follows: • $634 million to support commodity risk management collateral requirements in the normal course of business, including over-the-counter and exchange-traded transactions and collateral postings with ERCOT; • $36 million to support executory contracts and insurance agreements; • $55 million to support our REP financial requirements with the PUCT, and • $33 million for other credit support requirements. Litigation Litigation Related to EPA Reviews — In August 2013, the U.S. Department of Justice (DOJ), acting as the attorneys for the EPA, filed a civil enforcement lawsuit against Luminant in federal district court in Dallas, alleging violations of the Clean Air Act (CAA), including its New Source Review standards, at our Big Brown and Martin Lake generation facilities. In August 2015, the district court granted Luminant's motion to dismiss seven of the nine claims asserted by the EPA in the lawsuit. In January 2017, the EPA dismissed its two remaining claims with prejudice and the district court entered final judgment in Luminant's favor. In March 2017, the EPA and the Sierra Club appealed the final judgment to the U.S. Court of Appeals for the Fifth Circuit (Fifth Circuit Court). After the parties filed their respective briefs in the Fifth Circuit Court, the appeal was argued before the Fifth Circuit Court in March 2018. We believe that we have complied with all requirements of the CAA and intend to vigorously defend against the remaining allegations. The lawsuit requests (i) the maximum civil penalties available under the CAA to the government of up to $32,500 to $37,500 per day for each alleged violation, depending on the date of the alleged violation, and (ii) injunctive relief, including an order requiring the installation of best available control technology at the affected units. An adverse outcome could require substantial capital expenditures that cannot be determined at this time or retirement of the remaining plant at issue, Martin Lake, and could possibly require the payment of substantial penalties. The recent retirement of the Big Brown plant should have a favorable impact on this litigation. We cannot predict the outcome of these proceedings, including the financial effects, if any. Greenhouse Gas Emissions In August 2015, the EPA finalized rules to address greenhouse gas emissions from new, modified and reconstructed and existing electricity generation units, referred to as the Clean Power Plan, including rules for existing facilities that would establish state-specific emissions rate goals to reduce nationwide CO 2 emissions. Various parties (including Luminant) filed petitions for review in the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit Court) and subsequently, in January 2016, a coalition of states, industry (including Luminant) and other parties filed applications with the U.S. Supreme Court (Supreme Court) asking that the Supreme Court stay the rule while the D.C. Circuit Court reviews the legality of the rule for existing plants. In February 2016, the Supreme Court stayed the rule pending the conclusion of legal challenges on the rule before the D.C. Circuit Court and until the Supreme Court disposes of any subsequent petition for review. Oral argument on the merits of the legal challenges to the rule was heard in September 2016 before the entire D.C. Circuit Court. Following a March 2017 Executive Order entitled Promoting Energy Independence and Economic Growth issued by President Trump covering a number of matters, including the Clean Power Plan (Order), in April 2017, in accordance with the Order, the EPA published its intent to review the Clean Power Plan. In October 2017, the EPA issued a proposed rule that would repeal the Clean Power Plan, with the proposed repeal focusing on what the EPA believes to be the unlawful nature of the Clean Power Plan and asking for public comment on the EPA's interpretations of its authority under the Clean Air Act. In December 2017, the EPA published an advance notice of proposed rulemaking (ANPR) soliciting information from the public as the EPA considers proposing a future rule. Vistra Energy submitted comments on the ANPR in February 2018. Vistra Energy submitted comments to the proposed repeal in April 2018. While we cannot predict the outcome of these rulemakings and related legal proceedings, or estimate a range of reasonably probable costs, if the rules are ultimately implemented or upheld as they were issued, they could have a material impact on our results of operations, liquidity or financial condition. Cross-State Air Pollution Rule (CSAPR) In July 2011, the EPA issued the CSAPR, compliance with which would have required significant additional reductions of sulfur dioxide (SO 2 ) and nitrogen oxide (NO X ) emissions from our fossil fueled generation units. After certain EPA revisions to the rule, the CSAPR became effective January 1, 2015. With respect to Texas's SO 2 and annual NO X emission budgets, in November 2016, the EPA proposed to withdraw the CSAPR Federal Implementation Plan (FIP) addressing SO 2 and annual NO X for Texas and in September 2017, the EPA finalized its proposal to remove Texas from these annual CSAPR programs. The Sierra Club and the National Parks Conservation Association filed a petition for review in the D.C. Circuit Court challenging that final rule and Luminant intervened on behalf of the EPA. On April 10, 2018, the D.C. Circuit Court granted the EPA's and petitioners' motion to hold the case in abeyance pending the EPA's consideration of a pending petition for administrative reconsideration. As a result of the EPA's action, Texas electric generating units are no longer subject to the CSAPR annual SO 2 and NO X limits, but remain subject to the CSAPR's ozone season NO X requirements. While we cannot predict the outcome of future proceedings related to the CSAPR, based upon our current operating plans, including the recent retirements of our Monticello, Big Brown and Sandow 4 plants (see Note 3 ), we do not believe that the CSAPR in its current form will cause any material operational, financial or compliance issues to our business or require us to incur any material compliance costs. Regional Haze — Reasonable Progress and Long-Term Strategies The Regional Haze Program of the CAA establishes "as a national goal the prevention of any future, and the remedying of any existing, impairment of visibility in mandatory class I federal areas which impairment results from man-made pollution." In February 2009, the TCEQ submitted a State Implementation Plan (SIP) concerning regional haze (Regional Haze SIP) to the EPA. In December 2011, the EPA proposed a limited disapproval of the Regional Haze SIP due to its reliance on the Clean Air Interstate Rule (CAIR) instead of the EPA's replacement CSAPR program. The EPA finalized the limited disapproval of Texas's Regional Haze SIP in June 2012 and, on March 20, 2018, the D.C. Circuit Court issued a decision upholding the EPA's actions and denying all of Luminant's petitions for review. In January 2016, the EPA issued a final rule approving in part and disapproving in part Texas' SIP addressing the reasonable progress component of the Regional Haze program and issuing a FIP. The EPA's emission limits in the FIP assume additional control equipment for specific lignite/coal-fueled generation units across Texas, including new flue gas desulfurization systems (scrubbers) at seven electricity generating units and upgrades to existing scrubbers at seven generation units. Specifically, for Luminant, the EPA's FIP is based on new scrubbers at Big Brown Units 1 and 2 and Monticello Units 1 and 2 and scrubber upgrades at Martin Lake Units 1, 2 and 3, Monticello Unit 3 and Sandow Unit 4. Under the terms of the rule, subject to the legal proceedings described in the following paragraph, the scrubber upgrades would be required by February 2019, and the new scrubbers would be required by February 2021. In March 2016, Luminant and a number of other parties, including the State of Texas, filed petitions for review in the Fifth Circuit Court challenging the FIP's Texas requirements. Luminant and other parties also filed motions to stay the FIP while the court reviews the legality of the EPA's action. In July 2016, the Fifth Circuit Court denied the EPA's motion to dismiss Luminant's challenge to the FIP and granted the motions to stay filed by Luminant and the other parties pending final review of the petitions for review. The case was abated until the end of November 2016 in order to allow the parties to pursue settlement discussions. Settlement discussions were unsuccessful, and in December 2016 the EPA filed a motion seeking a voluntary remand of the rule back to the EPA for further consideration of Luminant's pending request for administrative reconsideration. In March 2017, the Fifth Circuit Court remanded the rule back to the EPA for reconsideration in light of the Court's prior determination that we and the other petitioners demonstrated a substantial likelihood that the EPA exceeded its statutory authority and acted arbitrarily and capriciously, but the Court denied all of the other pending motions. The stay of the rule (and the emission control requirements) remains in effect, and the EPA is required to file status reports of its reconsideration every 60 days. The recent retirements of our Monticello, Big Brown and Sandow 4 plants should have a favorable impact on this rulemaking and litigation. While we cannot predict the outcome of the rulemaking and legal proceedings, or estimate a range of reasonably possible costs, the result may have a material impact on our results of operations, liquidity or financial condition. Regional Haze — Best Available Retrofit Technology (BART) In September 2017, the EPA signed the final BART FIP for Texas, with the rule serving as a partial approval of Texas's 2009 SIP and a partial FIP. For SO 2 , the rule creates an intrastate Texas emission allowance trading program as a "BART alternative" that operates in a similar fashion to a CSAPR trading program. The program includes 39 generating units (including our Martin Lake, Big Brown, Monticello, Sandow 4, Stryker 2 and Graham 2 plants). The compliance obligations in the program will start on January 1, 2019 and the identified units will receive an annual allowance allocation that is equal to their most recent annual CSAPR SO 2 allocation. Luminant's units covered by the program are allocated 91,222 allowances annually. Under the rule, a unit that is listed that does not operate for two consecutive years starting after 2018 would no longer receive allowances after the fifth year of non-operation. We believe the recent retirements of our Monticello, Big Brown and Sandow 4 plants will enhance our ability to comply with this BART rule for SO 2 . For NO X , the rule adopts the CSAPR's ozone program as BART and for particulate matter, the rule approves Texas's SIP that determines that no electric generating units are subject to BART for particulate matter. The National Parks Conservation Association, the Sierra Club and the Environmental Defense Fund filed a petition challenging the rule in the Fifth Circuit Court as well as a petition for reconsideration filed with the EPA. In March 2018, the Fifth Circuit Court granted a joint motion filed by the EPA and the environmental groups involved to abate the Fifth Circuit Court proceedings until the EPA has taken action on the reconsideration petition and concludes the reconsideration process. While we cannot predict the outcome of the rulemaking and legal proceedings, we believe the rule, if ultimately implemented or upheld as issued, will not have a material impact on our results of operation, liquidity or financial condition. Affirmative Defenses During Malfunctions In February 2013, the EPA proposed a rule requiring certain states to replace SIP exemptions for excess emissions during malfunctions with an affirmative defense. Texas was not included in that original proposal since it already had an EPA-approved affirmative defense provision in its SIP that was found to be lawful by the Fifth Circuit Court in 2013. In May 2015, the EPA finalized its 2013 proposal to extend the EPA's proposed findings of inadequacy to states that have affirmative defense provisions, including Texas. The EPA's revised proposal would require Texas to remove or replace its EPA-approved affirmative defense provisions for excess emissions during startup, shutdown and maintenance events. In June 2015, the State of Texas and various industry parties (including Luminant) filed petitions for review in the Fifth Circuit Court challenging certain aspects of the EPA's final rule as they apply to the Texas SIP. In August 2015, the Fifth Circuit Court transferred the petitions that Luminant and other parties filed to the D.C. Circuit Court, and in October 2015 the petitions were consolidated with the pending petitions challenging the EPA's action in the D.C. Circuit Court. Before the originally scheduled oral argument was held, in April 2017, the court granted the EPA's motion to continue oral argument and ordered that the case be held in abeyance with the EPA to provide status reports to the court on the EPA's review of the action at 90-day intervals. We cannot predict the timing or outcome of this proceeding, or estimate a range of reasonably possible costs, but implementation of the rule as finalized may have a material impact on our results of operations, liquidity or financial condition. SO 2 Designations for Texas In November 2016, the EPA finalized its nonattainment designations for counties surrounding our Big Brown, Monticello and Martin Lake generation plants. The final designations require Texas to develop nonattainment plans for these areas. In February 2017, the State of Texas and Luminant filed challenges to the nonattainment designations in the Fifth Circuit Court. Subsequently, in October 2017, the Fifth Circuit Court granted the EPA's motion to hold the case in abeyance in light of the EPA's representation that it intended to revisit the nonattainment rule. In December 2017, the TCEQ submitted a petition for reconsideration to the EPA. In addition, with respect to Monticello and Big Brown, the retirement of those plants should favorably impact our legal challenge to the nonattainment designations in that the nonattainment designation for Freestone County and Titus County are based solely on the Sierra Club modeling, which we dispute, of alleged SO 2 emissions from Monticello and Big Brown. Regardless, considering these retirements, the nonattainment designation for those counties are no longer supported. While we cannot predict the outcome of this matter, or estimate a range of reasonably possible costs, the result may have a material impact on our results of operations, liquidity or financial condition. Litigation Related to the Merger In January 2018, a purported Dynegy stockholder filed a putative class action lawsuit in the U.S. District Court for the Southern Division of Texas, Houston Division, alleging that Dynegy, each member of the Dynegy board of directors and Vistra Energy violated federal securities laws by filing a Form S-4 Registration Statement in connection with the Merger that omitted purportedly material information. The lawsuit sought to enjoin the Merger and to have Dynegy and Vistra Energy issue an amended Form S-4 or, alternatively, damages if the Merger closed without an amended Form S-4 having been filed. Two other related lawsuits were also filed but neither of those named Vistra Energy. In February 2018, Vistra Energy and Dynegy filed supplemental disclosures to the Registration Statement and the plaintiffs agreed to forego any further effort to enjoin the Merger, dismiss the individual claims with prejudice, and dismissed without prejudice claims of the putative class following the stockholder vote on March 2, 2018. Other Matters We are involved in various legal and administrative proceedings in the normal course of business, the ultimate resolutions of which, in the opinion of management, are not anticipated to have a material effect on our results of operations, liquidity or financial condition.

Equity (Notes)

Equity (Notes)	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Equity	EQUITY Vistra Energy did not declare or pay any dividends during the three months ended March 31, 2018 and 2017 . The agreement governing the Vistra Operations Credit Facilities (the Credit Facilities Agreement) generally restricts the ability of Vistra Operations Company LLC (Vistra Operations) to make distributions to any direct or indirect parent unless such distributions are expressly permitted thereunder. As of March 31, 2018 , Vistra Operations can distribute approximately $975 million to Vistra Energy Corp. (the Parent) under the Credit Facilities Agreement without the consent of any party. The amount that can be distributed by Vistra Operations to the Parent was partially reduced by distributions made by Vistra Operations to the Parent during the year ended December 31, 2017 of approximately $1.1 billion . There were no distributions made by Vistra Operations to the Parent during the three months ended March 31, 2018 . Additionally, Vistra Operations may make distributions to the Parent in amounts sufficient for the Parent to make any payments required under the TRA or the Tax Matters Agreement or, to the extent arising out of the Parent's ownership or operation of Vistra Operations, to pay any taxes or general operating or corporate overhead expenses. As of March 31, 2018 , the maximum amount of restricted net assets of Vistra Operations that may not be distributed to the Parent totaled approximately $3.6 billion . Under applicable Delaware General Corporate Law, we are prohibited from paying any distribution to the extent that such distribution exceeds the value of our "surplus," which is defined as the excess of our net assets above our capital (the aggregate par value of all outstanding shares of our stock). The following table presents the changes to shareholder's equity for the three months ended March 31, 2018 : Common Stock (a) Additional Paid-in Capital Retained Earnings (Deficit) Accumulated Other Comprehensive Income (Loss) Total Shareholders' Equity Balance at December 31, 2017 $ 4 $ 7,765 $ (1,410 ) $ (17 ) $ 6,342 Net loss — — (306 ) — (306 ) Adoption of accounting standard (Note 1) — — 17 — 17 Effects of stock-based incentive compensation plans — 7 — — 7 Change in unrecognized losses related to pension and OPEB plans — — — 1 1 Other — — (1 ) — (1 ) Balance at March 31, 2018 $ 4 $ 7,772 $ (1,700 ) $ (16 ) $ 6,060 ________________ (a) Authorized shares totaled 1,800,000,000 at March 31, 2018 . Outstanding shares totaled 428,506,325 and 428,398,802 at March 31, 2018 and December 31, 2017 , respectively. The following table presents the changes to shareholder's equity for the three months ended March 31, 2017 : Common Stock (a) Additional Paid-in Capital Retained Earnings (Deficit) Accumulated Other Comprehensive Income (Loss) Total Shareholders' Equity Balance at December 31, 2016 $ 4 $ 7,742 $ (1,155 ) $ 6 $ 6,597 Net income — — 78 — 78 Effects of stock-based incentive compensation plans — 4 — — 4 Other — — 1 — 1 Balance at March 31, 2017 $ 4 $ 7,746 $ (1,076 ) $ 6 $ 6,680 ________________ (a) Authorized shares totaled 1,800,000,000 at March 31, 2017 . Outstanding shares totaled 427,587,401 and 427,580,232 at March 31, 2017 and December 31, 2016 , respectively.

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS We utilize several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those items that are measured on a recurring basis. We use a mid-market valuation convention (the mid-point price between bid and ask prices) as a practical expedient to measure fair value for the majority of our assets and liabilities and use valuation techniques to maximize the use of observable inputs and minimize the use of unobservable inputs. Our valuation policies and procedures were developed, maintained and validated by a centralized risk management group that reports to the Vistra Energy Chief Financial Officer. Fair value measurements of derivative assets and liabilities incorporate an adjustment for credit-related nonperformance risk. These nonperformance risk adjustments take into consideration master netting arrangements, credit enhancements and the credit risks associated with our credit standing and the credit standing of our counterparties (see Note 14 for additional information regarding credit risk associated with our derivatives). We utilize credit ratings and default rate factors in calculating these fair value measurement adjustments. We categorize our assets and liabilities recorded at fair value based upon the following fair value hierarchy: • Level 1 valuations use quoted prices in active markets for identical assets or liabilities that are accessible at the measurement date. Our Level 1 assets and liabilities include CME or ICE (electronic commodity derivative exchanges) futures and options transacted through clearing brokers for which prices are actively quoted. We report the fair value of CME and ICE transactions without taking into consideration margin deposits, with the exception of certain margin amounts related to changes in fair value on certain CME transactions that, beginning in January 2017, are legally characterized as settlement of derivative contracts rather than collateral. • Level 2 valuations utilize over-the-counter broker quotes, quoted prices for similar assets or liabilities that are corroborated by correlations or other mathematical means, and other valuation inputs such as interest rates and yield curves observable at commonly quoted intervals. We attempt to obtain multiple quotes from brokers that are active in the markets in which we participate and require at least one quote from two brokers to determine a pricing input as observable. The number of broker quotes received for certain pricing inputs varies depending on the depth of the trading market, each individual broker's publication policy, recent trading volume trends and various other factors. • Level 3 valuations use unobservable inputs for the asset or liability. Unobservable inputs are used to the extent observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. We use the most meaningful information available from the market combined with internally developed valuation methodologies to develop our best estimate of fair value. Significant unobservable inputs used to develop the valuation models include volatility curves, correlation curves, illiquid pricing delivery periods and locations and credit-related nonperformance risk assumptions. These inputs and valuation models are developed and maintained by employees trained and experienced in market operations and fair value measurements and validated by the Company's risk management group. With respect to amounts presented in the following fair value hierarchy tables, the fair value measurement of an asset or liability (e.g., a contract) is required to fall in its entirety in one level, based on the lowest level input that is significant to the fair value measurement. Assets and liabilities measured at fair value on a recurring basis consisted of the following at the respective balance sheet dates shown below: March 31, 2018 Level 1 Level 2 Level 3 (a) Reclassification (b) Total Assets: Commodity contracts $ 40 $ 286 $ 163 $ 7 $ 496 Interest rate swaps — 77 — — 77 Nuclear decommissioning trust – 465 — — — 465 Nuclear decommissioning trust – — 427 — — 427 Sub-total $ 505 $ 790 $ 163 $ 7 1,465 Assets measured at net asset value (d): Nuclear decommissioning trust – 288 Total assets $ 1,753 Liabilities: Commodity contracts $ 82 $ 505 $ 387 $ 7 $ 981 Total liabilities $ 82 $ 505 $ 387 $ 7 $ 981 December 31, 2017 Level 1 Level 2 Level 3 (a) Reclassification (b) Total Assets: Commodity contracts $ 47 $ 98 $ 75 $ 2 $ 222 Interest rate swaps — 18 — 8 26 Nuclear decommissioning trust – 468 — — — 468 Nuclear decommissioning trust – — 430 — — 430 Sub-total $ 515 $ 546 $ 75 $ 10 1,146 Assets measured at net asset value (d): Nuclear decommissioning trust – 290 Total assets $ 1,436 Liabilities: Commodity contracts $ 45 $ 143 $ 128 $ 2 $ 318 Interest rate swaps — — — 8 8 Total liabilities $ 45 $ 143 $ 128 $ 10 $ 326 ____________ (a) See table below for description of Level 3 assets and liabilities. (b) Fair values are determined on a contract basis, but certain contracts result in a current asset and a noncurrent liability, or vice versa, as presented in our condensed consolidated balance sheets. (c) The nuclear decommissioning trust investment is included in the other investments line in our condensed consolidated balance sheets. See Note 17 . (d) The fair value amounts presented in this line are intended to permit reconciliation of the fair value hierarchy to the amounts presented in our condensed consolidated balance sheets. Certain investments measured at fair value using the net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. Commodity contracts consist primarily of natural gas, electricity, coal, fuel oil and uranium agreements and include financial instruments entered into for economic hedging purposes as well as physical contracts that have not been designated as normal purchases or sales. Interest rate swaps are used to reduce exposure to interest rate changes by converting floating-rate interest to fixed rates. See Note 14 for further discussion regarding derivative instruments. Nuclear decommissioning trust assets represent securities held for the purpose of funding the future retirement and decommissioning of our nuclear generation facility. These investments include equity, debt and other fixed-income securities consistent with investment rules established by the NRC and the PUCT. The following tables present the fair value of the Level 3 assets and liabilities by major contract type and the significant unobservable inputs used in the valuations at March 31, 2018 and December 31, 2017 : March 31, 2018 Fair Value Contract Type (a) Assets Liabilities Total Valuation Technique Significant Unobservable Input Range (b) Electricity purchases and sales $ 41 $ (149 ) $ (108 ) Valuation Model Hourly price curve shape (c) $0 to $60/ MWh Illiquid delivery periods for ERCOT hub power prices and heat rates (d) $20 to $90/ MWh Electricity and weather options 41 (232 ) (191 ) Option Pricing Model Gas to power correlation (e) 40% to 100% Power volatility (e) 5% to 195% Electricity congestion revenue rights 66 (6 ) 60 Market Approach (f) Illiquid price differences between settlement points (g) $0 to $15/ MWh Other (h) 15 — 15 Total $ 163 $ (387 ) $ (224 ) December 31, 2017 Fair Value Contract Type (a) Assets Liabilities Total Valuation Technique Significant Unobservable Input Range (b) Electricity purchases and sales $ 12 $ (33 ) $ (21 ) Valuation Model Hourly price curve shape (c) $0 to $40/ MWh Illiquid delivery periods for ERCOT hub power prices and heat rates (d) $20 to $70/ MWh Electricity and weather options 10 (91 ) (81 ) Option Pricing Model Gas to power correlation (e) 30% to 100% Power volatility (e) 5% to 180% Electricity congestion revenue rights 45 (4 ) 41 Market Approach (f) Illiquid price differences between settlement points (g) $0 to $15/ MWh Other (h) 8 — 8 Total $ 75 $ (128 ) $ (53 ) ____________ (a) Electricity purchase and sales contracts include power and heat rate positions in ERCOT regions. Electricity congestion revenue rights contracts consist of forward purchase contracts (swaps and options) used to hedge electricity price differences between settlement points within ERCOT. Electricity options consist of physical electricity options and spread options. (b) The range of the inputs may be influenced by factors such as time of day, delivery period, season and location. (c) Based on the historical range of forward average hourly ERCOT North Hub prices. (d) Based on historical forward ERCOT power price and heat rate variability. (e) Based on historical forward correlation and volatility within ERCOT. (f) While we use the market approach, there is insufficient market data to consider the valuation liquid. (g) Based on the historical price differences between settlement points within ERCOT hubs and load zones. (h) Other includes contracts for natural gas and coal options. There were no transfers between Level 1 and Level 2 of the fair value hierarchy for the three months ended March 31, 2018 and 2017 . See the table below for discussion of transfers between Level 2 and Level 3 for the three months ended March 31, 2018 and 2017 . The following table presents the changes in fair value of the Level 3 assets and liabilities for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 Net asset (liability) balance at beginning of period $ (53 ) $ 83 Total unrealized valuation gains (losses) (213 ) 40 Purchases, issuances and settlements (a): Purchases 29 10 Issuances (4 ) (12 ) Settlements 17 (19 ) Transfers into Level 3 (b) — 3 Transfers out of Level 3 (b) — 2 Net change (c) (171 ) 24 Net asset (liability) balance at end of period $ (224 ) $ 107 Unrealized valuation gains (losses) relating to instruments held at end of period $ (206 ) $ 36 ____________ (a) Settlements reflect reversals of unrealized mark-to-market valuations previously recognized in net income. Purchases and issuances reflect option premiums paid or received. (b) Includes transfers due to changes in the observability of significant inputs. All Level 3 transfers during the periods presented are in and out of Level 2. (c) Activity excludes change in fair value in the month positions settle. Substantially all changes in value of commodity contracts are reported as operating revenues in our condensed statements of consolidated income (loss).

Commodity and Other Derivative

Commodity and Other Derivative Contractual Assets and Liabilities (Notes)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Commodity And Other Derivative Contractual Assets And Liabilities	COMMODITY AND OTHER DERIVATIVE CONTRACTUAL ASSETS AND LIABILITIES Strategic Use of Derivatives We transact in derivative instruments, such as options, swaps, futures and forward contracts, to manage commodity price and interest rate risk. See Note 13 for a discussion of the fair value of derivatives. Commodity Hedging and Trading Activity — We utilize natural gas and electricity derivatives to reduce exposure to changes in electricity prices primarily to hedge future revenues from electricity sales from our generation assets. We also utilize short-term electricity, natural gas, coal, fuel oil and uranium derivative instruments for fuel hedging and other purposes. Counterparties to these transactions include energy companies, financial institutions, electric utilities, independent power producers, oil and gas producers, local distribution companies and energy marketing companies. Unrealized gains and losses arising from changes in the fair value of derivative instruments as well as realized gains and losses upon settlement of the instruments are reported in our condensed statements of consolidated income (loss) in operating revenues and fuel, purchased power costs and delivery fees. Interest Rate Swaps — Interest rate swap agreements are used to reduce exposure to interest rate changes by converting floating-rate interest rates to fixed rates, thereby hedging future interest costs and related cash flows. Unrealized gains and losses arising from changes in the fair value of the swaps as well as realized gains and losses upon settlement of the swaps are reported in our condensed statements of consolidated income (loss) in interest expense and related charges. Financial Statement Effects of Derivatives Substantially all derivative contractual assets and liabilities are accounted for under mark-to-market accounting consistent with accounting standards related to derivative instruments and hedging activities. The following tables provide detail of derivative contractual assets and liabilities as reported in our condensed consolidated balance sheets at March 31, 2018 and December 31, 2017 . Derivative asset and liability totals represent the net value of the contract, while the balance sheet totals represent the gross value of the contract. March 31, 2018 Derivative Assets Derivative Liabilities Commodity Contracts Interest Rate Swaps Commodity Contracts Interest Rate Swaps Total Current assets $ 397 $ 3 $ 4 $ — $ 404 Noncurrent assets 95 74 — — 169 Current liabilities (2 ) — (593 ) — (595 ) Noncurrent liabilities (1 ) — (385 ) — (386 ) Net assets (liabilities) $ 489 $ 77 $ (974 ) $ — $ (408 ) December 31, 2017 Derivative Assets Derivative Liabilities Commodity Contracts Interest Rate Swaps Commodity Contracts Interest Rate Swaps Total Current assets $ 190 $ — $ — $ — $ 190 Noncurrent assets 30 22 2 4 58 Current liabilities — (4 ) (216 ) (4 ) (224 ) Noncurrent liabilities — — (102 ) — (102 ) Net assets (liabilities) $ 220 $ 18 $ (316 ) $ — $ (78 ) At March 31, 2018 and December 31, 2017 , there were no derivative positions accounted for as cash flow or fair value hedges. There were no amounts recognized in OCI for both the three months ended March 31, 2018 and 2017 . The following table presents the pretax effect of derivative gains (losses) on net income, including realized and unrealized effects. Amount represents changes in fair value of positions in the derivative portfolio during the period, as realized amounts related to positions settled are assumed to equal reversals of previously recorded unrealized amounts. Derivative (condensed statements of consolidated income (loss) presentation) Three Months Ended March 31, 2018 2017 Commodity contracts (Operating revenues) $ (446 ) $ 175 Commodity contracts (Fuel, purchased power costs and delivery fees) (1 ) (5 ) Interest rate swaps (Interest expense and related charges) 56 3 Net gain (loss) $ (391 ) $ 173 Balance Sheet Presentation of Derivatives We elect to report derivative assets and liabilities in our condensed consolidated balance sheets on a gross basis without taking into consideration netting arrangements we have with counterparties to those derivatives. We maintain standardized master netting agreements with certain counterparties that allow for the right to offset assets and liabilities and collateral in order to reduce credit exposure between us and the counterparty. These agreements contain specific language related to margin requirements, monthly settlement netting, cross-commodity netting and early termination netting, which is negotiated with the contract counterparty. Generally, margin deposits that contractually offset these derivative instruments are reported separately in our condensed consolidated balance sheets, with the exception of certain margin amounts related to changes in fair value on certain CME transactions that are legally characterized as settlement of forward exposure rather than collateral. Margin deposits received from counterparties are primarily used for working capital or other general corporate purposes. The following tables reconcile our derivative assets and liabilities on a contract basis to net amounts after taking into consideration netting arrangements with counterparties and financial collateral: March 31, 2018 December 31, 2017 Derivative Assets and Liabilities Offsetting Instruments (a) Cash Collateral (Received) Pledged (b) Net Amounts Derivative Assets and Liabilities Offsetting Instruments (a) Cash Collateral (Received) Pledged (b) Net Amounts Derivative assets: Commodity contracts $ 489 $ (277 ) $ (1 ) $ 211 $ 220 $ (113 ) $ (1 ) $ 106 Interest rate swaps 77 — — 77 18 — — 18 Total derivative assets 566 (277 ) (1 ) 288 238 (113 ) (1 ) 124 Derivative liabilities: Commodity contracts (974 ) 277 85 (612 ) (316 ) 113 1 (202 ) Interest rate swaps — — — — — — — — Total derivative liabilities (974 ) 277 85 (612 ) (316 ) 113 1 (202 ) Net amounts $ (408 ) $ — $ 84 $ (324 ) $ (78 ) $ — $ — $ (78 ) ____________ (a) Amounts presented exclude trade accounts receivable and payable related to settled financial instruments. (b) Represents cash amounts received or pledged pursuant to a master netting arrangement, including fair value-based margin requirements and, to a lesser extent, initial margin requirements. Derivative Volumes The following table presents the gross notional amounts of derivative volumes at March 31, 2018 and December 31, 2017 : March 31, 2018 December 31, 2017 Derivative type Notional Volume Unit of Measure Natural gas (a) 1,423 1,259 Million MMBtu Electricity 102,316 114,129 GWh Congestion Revenue Rights (b) 142,560 110,913 GWh Coal 2 2 Million U.S. tons Fuel oil 22 5 Million gallons Uranium 125 325 Thousand pounds Interest rate swaps – floating/fixed (c) $ 3,000 $ 3,000 Million U.S. dollars ____________ (a) Represents gross notional forward sales, purchases and options transactions, locational basis swaps and other natural gas transactions. (b) Represents gross forward purchases associated with instruments used to hedge electricity price differences between settlement points within ERCOT. (c) Includes notional amounts of interest rate swaps with maturity dates through July 2023. Credit Risk-Related Contingent Features of Derivatives Our derivative contracts may contain certain credit risk-related contingent features that could trigger liquidity requirements in the form of cash collateral, letters of credit or some other form of credit enhancement. Certain of these agreements require the posting of collateral if our credit rating is downgraded by one or more credit rating agencies or include cross-default contractual provisions that could result in the settlement of such contracts if there was a failure under other financing arrangements related to payment terms or other covenants. The following table presents the commodity derivative liabilities subject to credit risk-related contingent features that are not fully collateralized: March 31, December 31, Fair value of derivative contract liabilities (a) $ (758 ) $ (204 ) Offsetting fair value under netting arrangements (b) 215 103 Cash collateral and letters of credit 336 41 Liquidity exposure $ (207 ) $ (60 ) ____________ (a) Excludes fair value of contracts that contain contingent features that do not provide specific amounts to be posted if features are triggered, including provisions that generally provide the right to request additional collateral (material adverse change, performance assurance and other clauses). (b) Amounts include the offsetting fair value of in-the-money derivative contracts and net accounts receivable under master netting arrangements. Concentrations of Credit Risk Related to Derivatives We have concentrations of credit risk with the counterparties to our derivative contracts. At March 31, 2018 , total credit risk exposure to all counterparties related to derivative contracts totaled $634 million (including associated accounts receivable). The net exposure to those counterparties totaled $293 million at March 31, 2018 after taking into effect netting arrangements, setoff provisions and collateral, with the largest net exposure to a single counterparty totaling $77 million . At March 31, 2018 , the credit risk exposure to the banking and financial sector represented 29% of the total credit risk exposure and 29% of the net exposure. Exposure to banking and financial sector counterparties is considered to be within an acceptable level of risk tolerance because all of this exposure is with counterparties with investment grade credit ratings. However, this concentration increases the risk that a default by any of these counterparties would have a material effect on our financial condition, results of operations and liquidity. The transactions with these counterparties contain certain provisions that would require the counterparties to post collateral in the event of a material downgrade in their credit rating. We maintain credit risk policies with regard to our counterparties to minimize overall credit risk. These policies authorize specific risk mitigation tools including, but not limited to, use of standardized master agreements that allow for netting of positive and negative exposures associated with a single counterparty. Credit enhancements such as parent guarantees, letters of credit, surety bonds, liens on assets and margin deposits are also utilized. Prospective material changes in the payment history or financial condition of a counterparty or downgrade of its credit quality result in the reassessment of the credit limit with that counterparty. The process can result in the subsequent reduction of the credit limit or a request for additional financial assurances. An event of default by one or more counterparties could subsequently result in termination-related settlement payments that reduce available liquidity if amounts are owed to the counterparties related to the derivative contracts or delays in receipts of expected settlements if the counterparties owe amounts to us.

Related Party Transactions (Not

Related Party Transactions (Notes)	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS In connection with Emergence, we entered into agreements with certain of our affiliates and with parties who received shares of common stock and TRA Rights in exchange for their claims. Registration Rights Agreement Pursuant to the Plan of Reorganization, on the Effective Date, we entered into a Registration Rights Agreement (the Registration Rights Agreement) with certain selling stockholders providing for registration of the resale of the Vistra Energy common stock held by such selling stockholders. In December 2016, we filed a Form S-1 registration statement with the SEC to register for resale the shares of Vistra Energy common stock held by certain significant stockholders pursuant to the Registration Rights Agreement, which was declared effective by the SEC in May 2017. The registration statement was amended in March 2018. Among other things, under the terms of the Registration Rights Agreement: • we will be required to use reasonable best efforts to convert the Form S-1 registration statement into a registration statement on Form S-3 as soon as reasonably practicable after we become eligible to do so and to have such Form S-3 declared effective as promptly as practicable (but in no event more than 30 days after it is filed with the SEC); • if we propose to file certain types of registration statements under the Securities Act of 1933, as amended, with respect to an offering of equity securities, we will be required to use our reasonable best efforts to offer the other parties to the Registration Rights Agreement the opportunity to register all or part of their shares on the terms and conditions set forth in the Registration Rights Agreement; and • the selling stockholders received the right, subject to certain conditions and exceptions, to request that we file registration statements or amend or supplement registration statements, with the SEC for an underwritten offering of all or part of their respective shares of Vistra Energy common stock (a Demand Registration), and the Company is required to cause any such registration statement or amendment or supplement (a) to be filed with the SEC promptly and, in any event, on or before the date that is 45 days , in the case of a registration statement on Form S-1, or 30 days , in the case of a registration statement on Form S-3, after we receive the written request from the relevant selling stockholders to effectuate the Demand Registration and (b) to become effective as promptly as reasonably practicable and in any event no later than 120 days after it is initially filed. All expenses of registration under the Registration Rights Agreement, including the legal fees of one counsel retained by or on behalf of the selling stockholders, will be paid by us. Legal fee expenses paid or accrued by Vistra Energy on behalf of the selling stockholders totaled less than $1 million during both the three months ended March 31, 2018 and 2017 . Tax Receivable Agreement On the Effective Date, Vistra Energy entered into the TRA with a transfer agent on behalf of certain former first lien creditors of TCEH. See Note 8 for discussion of the TRA.

Segment Information (Notes)

Segment Information (Notes)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION The operations of Vistra Energy are aligned into three reportable business segments: Wholesale Generation, Retail Electricity and Asset Closure. Our chief operating decision maker reviews the results of these three segments separately and allocates resources to the respective segments as part of our strategic operations. The Wholesale Generation and Retail Electricity businesses offer different products or services and involve different risks. The Wholesale Generation segment is engaged in electricity generation, wholesale energy sales and purchases, commodity risk management activities, fuel production and fuel logistics management, all largely in the ERCOT market. These activities are substantially all conducted by Luminant. The Retail Electricity segment is engaged in retail sales of electricity and related services to residential, commercial and industrial customers, all largely in the ERCOT market. These activities are substantially all conducted by TXU Energy. As discussed in Note 1 , the Asset Closure segment was established effective January 1, 2018. The Asset Closure segment is engaged in the decommissioning and reclamation of retired plants and mines. Separately reporting the Asset Closure segment provides management with better information related to the performance and earnings power of Vistra Energy's ongoing operations and facilitates management's focus on minimizing the cost associated with decommissioning and reclamation of retired plants and mines. We have recast information from prior periods to reflect this change in reportable segments. We have not allocated any unrealized gains or losses to the Asset Closure segment for the generation plants that were retired in January and February 2018. Corporate and Other represents the remaining non-segment operations consisting primarily of general corporate expenses, interest, taxes and other expenses related to our support functions that provide shared services to our Wholesale Generation, Retail Electricity and Asset Closure segments. The accounting policies of the business segments are the same as those described in the summary of significant accounting policies in Note 1 to the Financial Statements in our 2017 Form 10-K. Our chief operating decision maker uses more than one measure to assess segment performance, including segment net income (loss), which is the measure most comparable to consolidated net income (loss) prepared based on GAAP. We account for intersegment sales and transfers as if the sales or transfers were to third parties, that is, at current market prices. Certain shared services costs are allocated to the segments. Three Months Ended March 31, 2018 2017 Operating revenues (a) Wholesale Generation $ (533 ) $ 785 Retail Electricity 972 865 Asset Closure 28 186 Corporate and Other — (1 ) Eliminations 298 (478 ) Consolidated operating revenues $ 765 $ 1,357 Depreciation and amortization Wholesale Generation $ (64 ) $ (53 ) Retail Electricity (76 ) $ (106 ) Corporate and Other (12 ) $ (11 ) Eliminations $ (1 ) $ — Consolidated depreciation and amortization $ (153 ) $ (170 ) Operating income (loss) Wholesale Generation $ (1,087 ) $ 300 Retail Electricity 757 $ (118 ) Asset Closure (23 ) $ (15 ) Corporate and Other (40 ) $ (12 ) Eliminations $ (1 ) $ — Consolidated operating income (loss) $ (394 ) $ 155 Net income (loss) Wholesale Generation $ (1,086 ) $ 303 Retail Electricity 771 (113 ) Asset Closure (22 ) (13 ) Corporate and Other 31 (99 ) Consolidated net income (loss) $ (306 ) $ 78 ____________ (a) For the three months ended March 31, 2018 and 2017 , includes third-party unrealized net gains (losses) from mark-to-market valuations of commodity positions of $(426) million and $126 million , respectively, recorded to the Wholesale Generation segment and $12 million and $8 million , respectively, recorded to the Retail Electricity segment. In addition, for the three months ended March 31, 2018 and 2017 , unrealized net gains (losses) with affiliate of $(643) million and $170 million , respectively, were recorded to operating revenues for the Wholesale Generation segment and corresponding unrealized net gains (losses) with affiliate of $643 million and $(170) million , respectively, were recorded to fuel, purchased power costs and delivery fees for the Retail Electricity segment, with no impact to consolidated results. March 31, December 31, 2017 Total assets Wholesale Generation $ 7,048 $ 6,834 Retail Electricity 6,890 6,156 Asset Closure 235 235 Corporate and Other and Eliminations 603 1,375 Consolidated total assets $ 14,776 $ 14,600

Supplementary Financial Informa

Supplementary Financial Information (Notes)	3 Months Ended
	Mar. 31, 2018
Supplementary Financial Information [Abstract]
Supplementary Financial Information	SUPPLEMENTARY FINANCIAL INFORMATION Interest Expense and Related Charges Three Months Ended March 31, 2018 2017 Interest paid/accrued $ 50 $ 54 Unrealized mark-to-market net gains on interest rate swaps (59 ) (9 ) Debt extinguishment gain — (21 ) Capitalized interest (3 ) (3 ) Other 3 3 Total interest expense and related charges $ (9 ) $ 24 The weighted average interest rate applicable to the Vistra Operations Credit Facilities, taking into account the interest rate swaps discussed in Note 10 , was 4.43% at March 31, 2018 . Other Income and Deductions Three Months Ended March 31, 2018 2017 Other income: Office space sublease rental income (a) $ 2 $ 3 Mineral rights royalty income (b) — 1 Sale of land (b) 1 2 Interest income 6 1 All other 1 2 Total other income $ 10 $ 9 Other deductions: All other $ 2 $ — Total other deductions $ 2 $ — ____________ (a) Reported in Corporate and Other non-segment. (b) Reported in Wholesale Generation segment. Restricted Cash March 31, 2018 December 31, 2017 Current Noncurrent Assets Current Noncurrent Assets Amounts related to the Vistra Operations Credit Facilities (Note 10) $ — $ 500 $ — $ 500 Amounts related to restructuring escrow accounts 59 — 59 — Total restricted cash $ 59 $ 500 $ 59 $ 500 Trade Accounts Receivable March 31, December 31, Wholesale and retail trade accounts receivable $ 477 $ 596 Allowance for uncollectible accounts (14 ) (14 ) Trade accounts receivable — net $ 463 $ 582 Gross trade accounts receivable at March 31, 2018 and December 31, 2017 included unbilled retail revenues of $187 million and $251 million , respectively. Allowance for Uncollectible Accounts Receivable Three Months Ended March 31, 2018 2017 Allowance for uncollectible accounts receivable at beginning of period $ 14 $ 10 Increase for bad debt expense 11 7 Decrease for account write-offs (11 ) (9 ) Allowance for uncollectible accounts receivable at end of period $ 14 $ 8 Inventories by Major Category March 31, December 31, Materials and supplies $ 149 $ 149 Fuel stock 62 83 Natural gas in storage 15 21 Total inventories $ 226 $ 253 Other Investments March 31, December 31, Nuclear plant decommissioning trust $ 1,180 $ 1,188 Land 49 49 Miscellaneous other 3 3 Total other investments $ 1,232 $ 1,240 Nuclear Decommissioning Trust — Investments in a trust that will be used to fund the costs to decommission the Comanche Peak nuclear generation plant are carried at fair value. Decommissioning costs are being recovered from Oncor's customers as a delivery fee surcharge over the life of the plant and deposited by Vistra Energy in the trust fund. Income and expense associated with the trust fund and the decommissioning liability are offset by a corresponding change in a receivable/payable (currently a receivable reported in noncurrent assets) that will ultimately be settled through changes in Oncor's delivery fees rates. A summary of investments in the fund follows: March 31, 2018 Cost (a) Unrealized gain Unrealized loss Fair market value Debt securities (b) $ 425 $ 8 $ (6 ) $ 427 Equity securities (c) 268 487 (2 ) 753 Total $ 693 $ 495 $ (8 ) $ 1,180 December 31, 2017 Cost (a) Unrealized gain Unrealized loss Fair market value Debt securities (b) $ 418 $ 14 $ (2 ) $ 430 Equity securities (c) 265 495 (2 ) 758 Total $ 683 $ 509 $ (4 ) $ 1,188 ____________ (a) Includes realized gains and losses on securities sold. (b) The investment objective for debt securities is to invest in a diversified tax efficient portfolio with an overall portfolio rating of AA or above as graded by S&P or Aa2 by Moody's Investors Services, Inc. The debt securities are heavily weighted with government and municipal bonds and investment grade corporate bonds. The debt securities had an average coupon rate of 3.45% and 3.55% at March 31, 2018 and December 31, 2017 , respectively, and an average maturity of nine years at both March 31, 2018 and December 31, 2017 . (c) The investment objective for equity securities is to invest tax efficiently and to match the performance of the S&P 500 Index. Debt securities held at March 31, 2018 mature as follows: $133 million in one to five years, $91 million in five to 10 years and $203 million after 10 years. The following table summarizes proceeds from sales of available-for-sale securities and the related realized gains and losses from such sales. Three Months Ended March 31, 2018 2017 Realized gains $ — $ 1 Realized losses $ (2 ) $ (2 ) Proceeds from sales of securities $ 46 $ 79 Investments in securities $ (51 ) $ (84 ) Property, Plant and Equipment At March 31, 2018 and December 31, 2017 , property, plant and equipment of $4.850 billion and $4.820 billion , respectively, is stated net of accumulated depreciation and amortization of $480 million and $393 million , respectively. Asset Retirement and Mining Reclamation Obligations (ARO) These liabilities primarily relate to nuclear generation plant decommissioning, land reclamation related to lignite mining, removal of lignite/coal fueled plant ash treatment facilities and generation plant asbestos removal and disposal costs. There is no earnings impact with respect to changes in the nuclear plant decommissioning liability, as all costs are recoverable through the regulatory process as part of delivery fees charged by Oncor. At March 31, 2018 , the carrying value of our ARO related to our nuclear generation plant decommissioning totaled $1.244 billion , which exceeds the fair value of the assets contained in the nuclear decommissioning trust. Since the costs to ultimately decommission that plant are recoverable through the regulatory rate making process as part of Oncor's delivery fees, a corresponding regulatory asset has been recorded to our condensed consolidated balance sheet of $64 million in other noncurrent assets. The following table summarizes the changes to these obligations, reported as asset retirement obligations (current and noncurrent liabilities) in our condensed consolidated balance sheets, for the three months ended March 31, 2018 : Nuclear Plant Decommissioning Mining Land Reclamation Other Total Liability at December 31, 2017 $ 1,233 $ 438 $ 265 $ 1,936 Additions: Accretion 11 5 3 19 Adjustment for change in estimates — 4 — 4 Reductions: Payments — (16 ) — (16 ) Liability at March 31, 2018 1,244 431 268 1,943 Less amounts due currently — (117 ) (9 ) (126 ) Noncurrent liability at March 31, 2018 $ 1,244 $ 314 $ 259 $ 1,817 Other Noncurrent Liabilities and Deferred Credits The balance of other noncurrent liabilities and deferred credits consists of the following: March 31, December 31, Unfavorable purchase and sales contracts $ 32 $ 36 Other, including retirement and other employee benefits 207 220 Total other noncurrent liabilities and deferred credits $ 239 $ 256 Unfavorable Purchase and Sales Contracts — The amortization of unfavorable purchase and sales contracts totaled $4 million and $3 million for the three months ended March 31, 2018 and 2017 , respectively. See Note 6 for intangible assets related to favorable purchase and sales contracts. The estimated amortization of unfavorable purchase and sales contracts for each of the next five fiscal years is as follows: Year Amount 2018 $ 11 2019 $ 9 2020 $ 9 2021 $ 1 2022 $ 3 Fair Value of Debt March 31, 2018 December 31, 2017 Debt: Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt under the Vistra Operations Credit Facilities (Note 10) $ 4,313 $ 4,328 $ 4,323 $ 4,334 Other long-term debt, excluding capital lease obligations (Note 10) 27 24 30 27 Mandatorily redeemable subsidiary preferred stock (Note 10) 70 70 70 70 We determine fair value in accordance with accounting standards as discussed in Note 13 , and at March 31, 2018 , our debt fair value represents Level 2 valuations. We obtain security pricing from an independent party who uses broker quotes and third-party pricing services to determine fair values. Where relevant, these prices are validated through subscription services such as Bloomberg. Cash Flow Information The following table reconciles cash, cash equivalents and restricted cash reported in our condensed statements of consolidated cash flows to the amounts reported in our condensed balance sheets at March 31, 2018 and December 31, 2017 : March 31, December 31, Cash and cash equivalents $ 1,379 $ 1,487 Restricted cash included in current assets 59 59 Restricted cash included in noncurrent assets 500 500 Total cash, cash equivalents and restricted cash $ 1,938 $ 2,046 The following table summarizes our supplemental cash flow information for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 2017 Cash payments related to: Interest paid $ 65 $ 89 Capitalized interest (3 ) (3 ) Interest paid (net of capitalized interest) $ 62 $ 86 Noncash investing and financing activities: Construction expenditures (a) $ 26 $ 1 ____________ (a) Represents end-of-period accruals for ongoing construction projects.

Business And Significant Acco25

Business And Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and on the same basis as the audited financial statements included in our 2017 Form 10-K, with the exception of the change in reporting segments as detailed above. Adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the results of operations and financial position have been included therein. All intercompany items and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been omitted pursuant to the rules and regulations of the SEC. Because the condensed consolidated interim financial statements do not include all of the information and footnotes required by U.S. GAAP, they should be read in conjunction with the audited financial statements and related notes contained in our 2017 Form 10-K. The results of operations for an interim period may not give a true indication of results for a full year. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated.
Use of Estimates	Use of Estimates Preparation of financial statements requires estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements, estimates of expected obligations, judgment related to the potential timing of events and other estimates. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information.

Business And Significant Acco26

Business And Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of new accounting pronouncements and changes in accounting principles	As of January 1, 2018, the cumulative effect of the changes made to our condensed consolidated balance sheet for the adoption of the new revenue standard was as follows: December 31, 2017 Adoption of New Revenue Standard January 1, 2018 Impact on condensed consolidated balance sheet: Assets Prepaid expense and other current assets $ 72 $ 5 $ 77 Accumulated deferred income taxes $ 710 $ (4 ) $ 706 Other noncurrent assets $ 162 $ 16 $ 178 Equity Retained deficit $ (1,410 ) $ 17 $ (1,393 ) In accordance with the new revenue standard requirements, the disclosure of the impact of adoption on our condensed statement of consolidated income (loss) and condensed consolidated balance sheet was as follows: Three Months Ended March 31, 2018 As Reported Amount Without Adoption of New Revenue Standard Effect of Change Higher (Lower) Impact on condensed statement of consolidated income (loss): Operating revenues $ 765 $ 764 $ 1 Selling, general and administrative expenses $ (162 ) $ (165 ) $ 3 Net income (loss) (306 ) (309 ) 3 March 31, 2018 As Reported Balances Without Adoption of New Revenue Standard Effect of Change Higher (Lower) Impact on condensed consolidated balance sheet: Assets Prepaid expense and other current assets $ 75 $ 69 $ 6 Accumulated deferred income taxes $ 793 $ 797 $ (4 ) Other noncurrent assets $ 189 $ 169 $ 20 Equity Retained deficit $ (1,700 ) $ (1,720 ) $ 20

Retirement of Generation Fac27

Retirement of Generation Facilities (Tables)	3 Months Ended
	Mar. 31, 2018
Retirement of Generation Facilities [Abstract]
Retirements of generation capacity	In January and February 2018, we retired three power plants with a total installed nameplate generation capacity of 4,167 MW. Luminant decided to retire these units because they were projected to be uneconomic based on current market conditions and would have faced significant environmental costs associated with operating such units. In the case of the Sandow units, the decision also reflected the execution of a contract termination agreement pursuant to which the Company and Alcoa agreed to an early settlement of a long-standing power and mining agreement. The following table details the units retired. Name Location (all in the state of Texas) Fuel Type Installed Nameplate Generation Capacity (MW) Number of Units Date Units Taken Offline Monticello Titus County Lignite/Coal 1,880 3 January 4, 2018 Sandow Milam County Lignite 1,137 2 January 11, 2018 Big Brown Freestone County Lignite/Coal 1,150 2 February 12, 2018 Total 4,167 7

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue Recognition and Deferred Revenue [Abstract]
Disaggregation of revenue	The following table disaggregates our revenue by major source: Three Months Ended March 31, 2018 Retail Electricity Wholesale Generation Asset Closure Eliminations Consolidated Revenue from contracts with customers: Revenue from Oncor service area $ 662 $ — $ — $ — $ 662 Revenue from other TDSP service areas 287 — — — 287 Wholesale generation revenue from ERCOT — 174 36 — 210 Revenue from non-affiliated REPs — 19 — — 19 Revenue from other wholesale contracts — 34 — — 34 Total revenue from contracts with customers 949 227 36 — 1,212 Other revenues: Retail contract amortization (12 ) — — — (12 ) Hedging and other revenues 35 (462 ) (8 ) — (435 ) Affiliate sales — (298 ) — 298 — Total other revenues 23 (760 ) (8 ) 298 (447 ) Total revenues $ 972 $ (533 ) $ 28 $ 298 $ 765
Accounts receivable, contracts with customers	Accounts Receivable The following table presents trade accounts receivable relating to both contracts with customers and other activities: March 31, 2018 Trade accounts receivable from contracts with customers — net $ 415 Other trade accounts receivable — net 48 Total trade accounts receivable — net $ 463

Goodwill and Identifiable Int29

Goodwill and Identifiable Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of identifiable intangible assets reported in the balance sheet	Identifiable intangible assets are comprised of the following: March 31, 2018 December 31, 2017 Identifiable Intangible Asset Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Retail customer relationship $ 1,648 $ 645 $ 1,003 $ 1,648 $ 572 $ 1,076 Software and other technology-related assets 186 57 129 183 47 136 Retail and wholesale contracts 154 99 55 154 87 67 Other identifiable intangible assets (a) 33 11 22 33 11 22 Total identifiable intangible assets subject to amortization $ 2,021 $ 812 1,209 $ 2,018 $ 717 1,301 Retail trade names (not subject to amortization) 1,225 1,225 Mineral interests (not currently subject to amortization) 3 4 Total identifiable intangible assets $ 2,437 $ 2,530 ____________ (a) Includes mining development costs and environmental allowances and credits.
Schedule of amortization expense related to intangible assets (including income statement line item)	Amortization expense related to finite-lived identifiable intangible assets (including the classification in the condensed statements of consolidated income (loss)) consisted of: Identifiable Intangible Asset Condensed Statements of Consolidated Income (Loss) Line Three Months Ended March 31, 2018 2017 Retail customer relationship Depreciation and amortization $ 73 $ 105 Software and other technology-related assets Depreciation and amortization 10 8 Retail and wholesale contracts Operating revenues/fuel, purchased power costs and delivery fees 12 28 Other identifiable intangible assets Operating revenues/fuel, purchased power costs and delivery fees/depreciation and amortization 2 4 Total amortization expense (a) $ 97 $ 145 ____________ (a) Amounts recorded in depreciation and amortization totaled $85 million and $115 million for the three months ended March 31, 2018 and 2017 , respectively.
Schedule of estimated amortization expense of identifiable intangible assets	As of March 31, 2018 , the estimated aggregate amortization expense of identifiable intangible assets for each of the next five fiscal years is as shown below. Year Estimated Amortization Expense 2018 $ 368 2019 $ 268 2020 $ 192 2021 $ 142 2022 $ 89

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Calculation of effective income tax rate	The calculation of our effective tax rate is as follows: Three Months Ended March 31, 2018 2017 Income (loss) before income taxes $ (395 ) $ 119 Income tax benefit (expense) $ 89 $ (41 ) Effective tax rate 22.5 % 34.5 %

Tax Receivable Agreement Obli31

Tax Receivable Agreement Obligation (Tables)	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Tax receivable agreement obligation	The following table summarizes the changes to the TRA obligation, reported as other current liabilities and Tax Receivable Agreement obligation in our condensed consolidated balance sheets, for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 2017 TRA obligation at the beginning of the period $ 357 $ 596 Accretion expense 18 21 TRA obligation at the end of the period 375 617 Less amounts due currently (24 ) (16 ) Noncurrent TRA obligation at the end of the period $ 351 $ 601

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of earnings per share, basic and diluted	Basic earnings per share available to common shareholders are based on the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated using the treasury stock method and includes the effect of all potential issuances of common shares under stock-based incentive compensation arrangements. Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Net Loss Shares Per Share Amount Net Income Shares Per Share Amount Net income (loss) available for common stock — basic $ (306 ) 428,450,384 $ (0.71 ) $ 78 427,583,339 $ 0.18 Dilutive securities: Stock-based incentive compensation plan — — — — 217,011 — Net income (loss) available for common stock — diluted $ (306 ) 428,450,384 $ (0.71 ) $ 78 427,800,350 $ 0.18

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	Amounts in the table below represent the categories of long-term debt obligations incurred by the Company. March 31, December 31, Vistra Operations Credit Facilities (a) $ 4,313 $ 4,323 Mandatorily redeemable subsidiary preferred stock (b) 70 70 8.82% Building Financing due semiannually through February 11, 2022 (c) 27 30 Total long-term debt including amounts due currently 4,410 4,423 Less amounts due currently (44 ) (44 ) Total long-term debt less amounts due currently $ 4,366 $ 4,379 ____________ (a) At March 31, 2018 , borrowings under the Vistra Operations Credit Facilities in our condensed consolidated balance sheet include debt premiums of $19 million , debt discounts of $2 million and debt issuance costs of $6 million . At December 31, 2017 , borrowings under the Vistra Operations Credit Facilities in our condensed consolidated balance sheet include debt premiums of $21 million , debt discounts of $2 million and debt issuance costs of $7 million . (b) Shares of mandatorily redeemable preferred stock in PrefCo issued as part of the Spin-Off (see Note 1 ). This subsidiary preferred stock is accounted for as a debt instrument under relevant accounting guidance. (c) Obligation related to a corporate office space capital lease. This obligation will be funded by amounts held in an escrow account that is reflected in other noncurrent assets in our condensed consolidated balance sheets.
Schedule of line of credit facilities	The Vistra Operations Credit Facilities and related available capacity at March 31, 2018 are presented below. March 31, 2018 Vistra Operations Credit Facilities Maturity Date Facility Limit Cash Borrowings Available Capacity Revolving Credit Facility (a) August 4, 2021 $ 860 $ — $ 584 Initial Term Loan B Facility (b) August 4, 2023 2,814 2,814 — Incremental Term Loan B Facility (b) December 14, 2023 988 988 — Term Loan C Facility (c) August 4, 2023 500 500 18 Total Vistra Operations Credit Facilities $ 5,162 $ 4,302 $ 602 ___________ (a) Facility to be used for general corporate purposes. Facility includes a $715 million letter of credit sub-facility, of which $276 million of letters of credit were outstanding at March 31, 2018 . (b) Cash borrowings under the Term Loan B Facility reflect required scheduled quarterly payment in annual amount equal to 1% of the original principal amount with the balance paid at maturity. Principal amounts paid cannot be reborrowed. (c) Facility used for issuing letters of credit for general corporate purposes. Borrowings under this facility were funded to collateral accounts that are reported as restricted cash in our condensed consolidated balance sheets. At March 31, 2018 , the restricted cash supported $482 million in letters of credit outstanding (see Note 17 ), leaving $18 million in available letter of credit capacity.

Equity (Tables)

Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Schedule of stockholders equity	The following table presents the changes to shareholder's equity for the three months ended March 31, 2018 : Common Stock (a) Additional Paid-in Capital Retained Earnings (Deficit) Accumulated Other Comprehensive Income (Loss) Total Shareholders' Equity Balance at December 31, 2017 $ 4 $ 7,765 $ (1,410 ) $ (17 ) $ 6,342 Net loss — — (306 ) — (306 ) Adoption of accounting standard (Note 1) — — 17 — 17 Effects of stock-based incentive compensation plans — 7 — — 7 Change in unrecognized losses related to pension and OPEB plans — — — 1 1 Other — — (1 ) — (1 ) Balance at March 31, 2018 $ 4 $ 7,772 $ (1,700 ) $ (16 ) $ 6,060 ________________ (a) Authorized shares totaled 1,800,000,000 at March 31, 2018 . Outstanding shares totaled 428,506,325 and 428,398,802 at March 31, 2018 and December 31, 2017 , respectively. The following table presents the changes to shareholder's equity for the three months ended March 31, 2017 : Common Stock (a) Additional Paid-in Capital Retained Earnings (Deficit) Accumulated Other Comprehensive Income (Loss) Total Shareholders' Equity Balance at December 31, 2016 $ 4 $ 7,742 $ (1,155 ) $ 6 $ 6,597 Net income — — 78 — 78 Effects of stock-based incentive compensation plans — 4 — — 4 Other — — 1 — 1 Balance at March 31, 2017 $ 4 $ 7,746 $ (1,076 ) $ 6 $ 6,680 ________________ (a) Authorized shares totaled 1,800,000,000 at March 31, 2017 . Outstanding shares totaled 427,587,401 and 427,580,232 at March 31, 2017 and December 31, 2016 , respectively.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis	Assets and liabilities measured at fair value on a recurring basis consisted of the following at the respective balance sheet dates shown below: March 31, 2018 Level 1 Level 2 Level 3 (a) Reclassification (b) Total Assets: Commodity contracts $ 40 $ 286 $ 163 $ 7 $ 496 Interest rate swaps — 77 — — 77 Nuclear decommissioning trust – 465 — — — 465 Nuclear decommissioning trust – — 427 — — 427 Sub-total $ 505 $ 790 $ 163 $ 7 1,465 Assets measured at net asset value (d): Nuclear decommissioning trust – 288 Total assets $ 1,753 Liabilities: Commodity contracts $ 82 $ 505 $ 387 $ 7 $ 981 Total liabilities $ 82 $ 505 $ 387 $ 7 $ 981 December 31, 2017 Level 1 Level 2 Level 3 (a) Reclassification (b) Total Assets: Commodity contracts $ 47 $ 98 $ 75 $ 2 $ 222 Interest rate swaps — 18 — 8 26 Nuclear decommissioning trust – 468 — — — 468 Nuclear decommissioning trust – — 430 — — 430 Sub-total $ 515 $ 546 $ 75 $ 10 1,146 Assets measured at net asset value (d): Nuclear decommissioning trust – 290 Total assets $ 1,436 Liabilities: Commodity contracts $ 45 $ 143 $ 128 $ 2 $ 318 Interest rate swaps — — — 8 8 Total liabilities $ 45 $ 143 $ 128 $ 10 $ 326 ____________ (a) See table below for description of Level 3 assets and liabilities. (b) Fair values are determined on a contract basis, but certain contracts result in a current asset and a noncurrent liability, or vice versa, as presented in our condensed consolidated balance sheets. (c) The nuclear decommissioning trust investment is included in the other investments line in our condensed consolidated balance sheets. See Note 17 . (d) The fair value amounts presented in this line are intended to permit reconciliation of the fair value hierarchy to the amounts presented in our condensed consolidated balance sheets. Certain investments measured at fair value using the net asset value per share (or its equivalent) have not been classified in the fair value hierarchy.
Schedule of fair value of the Level 3 assets and liabilities by major contract type (all related to commodity contracts) and the significant unobservable inputs used in the valuations	The following tables present the fair value of the Level 3 assets and liabilities by major contract type and the significant unobservable inputs used in the valuations at March 31, 2018 and December 31, 2017 : March 31, 2018 Fair Value Contract Type (a) Assets Liabilities Total Valuation Technique Significant Unobservable Input Range (b) Electricity purchases and sales $ 41 $ (149 ) $ (108 ) Valuation Model Hourly price curve shape (c) $0 to $60/ MWh Illiquid delivery periods for ERCOT hub power prices and heat rates (d) $20 to $90/ MWh Electricity and weather options 41 (232 ) (191 ) Option Pricing Model Gas to power correlation (e) 40% to 100% Power volatility (e) 5% to 195% Electricity congestion revenue rights 66 (6 ) 60 Market Approach (f) Illiquid price differences between settlement points (g) $0 to $15/ MWh Other (h) 15 — 15 Total $ 163 $ (387 ) $ (224 ) December 31, 2017 Fair Value Contract Type (a) Assets Liabilities Total Valuation Technique Significant Unobservable Input Range (b) Electricity purchases and sales $ 12 $ (33 ) $ (21 ) Valuation Model Hourly price curve shape (c) $0 to $40/ MWh Illiquid delivery periods for ERCOT hub power prices and heat rates (d) $20 to $70/ MWh Electricity and weather options 10 (91 ) (81 ) Option Pricing Model Gas to power correlation (e) 30% to 100% Power volatility (e) 5% to 180% Electricity congestion revenue rights 45 (4 ) 41 Market Approach (f) Illiquid price differences between settlement points (g) $0 to $15/ MWh Other (h) 8 — 8 Total $ 75 $ (128 ) $ (53 ) ____________ (a) Electricity purchase and sales contracts include power and heat rate positions in ERCOT regions. Electricity congestion revenue rights contracts consist of forward purchase contracts (swaps and options) used to hedge electricity price differences between settlement points within ERCOT. Electricity options consist of physical electricity options and spread options. (b) The range of the inputs may be influenced by factors such as time of day, delivery period, season and location. (c) Based on the historical range of forward average hourly ERCOT North Hub prices. (d) Based on historical forward ERCOT power price and heat rate variability. (e) Based on historical forward correlation and volatility within ERCOT. (f) While we use the market approach, there is insufficient market data to consider the valuation liquid. (g) Based on the historical price differences between settlement points within ERCOT hubs and load zones. (h) Other includes contracts for natural gas and coal options.
Schedule of changes in fair value of the Level 3 assets and liabilities	The following table presents the changes in fair value of the Level 3 assets and liabilities for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 Net asset (liability) balance at beginning of period $ (53 ) $ 83 Total unrealized valuation gains (losses) (213 ) 40 Purchases, issuances and settlements (a): Purchases 29 10 Issuances (4 ) (12 ) Settlements 17 (19 ) Transfers into Level 3 (b) — 3 Transfers out of Level 3 (b) — 2 Net change (c) (171 ) 24 Net asset (liability) balance at end of period $ (224 ) $ 107 Unrealized valuation gains (losses) relating to instruments held at end of period $ (206 ) $ 36 ____________ (a) Settlements reflect reversals of unrealized mark-to-market valuations previously recognized in net income. Purchases and issuances reflect option premiums paid or received. (b) Includes transfers due to changes in the observability of significant inputs. All Level 3 transfers during the periods presented are in and out of Level 2. (c) Activity excludes change in fair value in the month positions settle. Substantially all changes in value of commodity contracts are reported as operating revenues in our condensed statements of consolidated income (loss).

Commodity and Other Derivativ36

Commodity and Other Derivative Contractual Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of commodity and other derivative contractual assets and liabilities as reported in the balance sheets	Substantially all derivative contractual assets and liabilities are accounted for under mark-to-market accounting consistent with accounting standards related to derivative instruments and hedging activities. The following tables provide detail of derivative contractual assets and liabilities as reported in our condensed consolidated balance sheets at March 31, 2018 and December 31, 2017 . Derivative asset and liability totals represent the net value of the contract, while the balance sheet totals represent the gross value of the contract. March 31, 2018 Derivative Assets Derivative Liabilities Commodity Contracts Interest Rate Swaps Commodity Contracts Interest Rate Swaps Total Current assets $ 397 $ 3 $ 4 $ — $ 404 Noncurrent assets 95 74 — — 169 Current liabilities (2 ) — (593 ) — (595 ) Noncurrent liabilities (1 ) — (385 ) — (386 ) Net assets (liabilities) $ 489 $ 77 $ (974 ) $ — $ (408 ) December 31, 2017 Derivative Assets Derivative Liabilities Commodity Contracts Interest Rate Swaps Commodity Contracts Interest Rate Swaps Total Current assets $ 190 $ — $ — $ — $ 190 Noncurrent assets 30 22 2 4 58 Current liabilities — (4 ) (216 ) (4 ) (224 ) Noncurrent liabilities — — (102 ) — (102 ) Net assets (liabilities) $ 220 $ 18 $ (316 ) $ — $ (78 )
Schedule of pretax effect on net income of derivatives not under hedge accounting, including realized and unrealized effects	The following table presents the pretax effect of derivative gains (losses) on net income, including realized and unrealized effects. Amount represents changes in fair value of positions in the derivative portfolio during the period, as realized amounts related to positions settled are assumed to equal reversals of previously recorded unrealized amounts. Derivative (condensed statements of consolidated income (loss) presentation) Three Months Ended March 31, 2018 2017 Commodity contracts (Operating revenues) $ (446 ) $ 175 Commodity contracts (Fuel, purchased power costs and delivery fees) (1 ) (5 ) Interest rate swaps (Interest expense and related charges) 56 3 Net gain (loss) $ (391 ) $ 173
Offsetting assets and liabilities	The following tables reconcile our derivative assets and liabilities on a contract basis to net amounts after taking into consideration netting arrangements with counterparties and financial collateral: March 31, 2018 December 31, 2017 Derivative Assets and Liabilities Offsetting Instruments (a) Cash Collateral (Received) Pledged (b) Net Amounts Derivative Assets and Liabilities Offsetting Instruments (a) Cash Collateral (Received) Pledged (b) Net Amounts Derivative assets: Commodity contracts $ 489 $ (277 ) $ (1 ) $ 211 $ 220 $ (113 ) $ (1 ) $ 106 Interest rate swaps 77 — — 77 18 — — 18 Total derivative assets 566 (277 ) (1 ) 288 238 (113 ) (1 ) 124 Derivative liabilities: Commodity contracts (974 ) 277 85 (612 ) (316 ) 113 1 (202 ) Interest rate swaps — — — — — — — — Total derivative liabilities (974 ) 277 85 (612 ) (316 ) 113 1 (202 ) Net amounts $ (408 ) $ — $ 84 $ (324 ) $ (78 ) $ — $ — $ (78 ) ____________ (a) Amounts presented exclude trade accounts receivable and payable related to settled financial instruments. (b) Represents cash amounts received or pledged pursuant to a master netting arrangement, including fair value-based margin requirements and, to a lesser extent, initial margin requirements.
Schedule of gross notional amounts of derivative volumes	The following table presents the gross notional amounts of derivative volumes at March 31, 2018 and December 31, 2017 : March 31, 2018 December 31, 2017 Derivative type Notional Volume Unit of Measure Natural gas (a) 1,423 1,259 Million MMBtu Electricity 102,316 114,129 GWh Congestion Revenue Rights (b) 142,560 110,913 GWh Coal 2 2 Million U.S. tons Fuel oil 22 5 Million gallons Uranium 125 325 Thousand pounds Interest rate swaps – floating/fixed (c) $ 3,000 $ 3,000 Million U.S. dollars ____________ (a) Represents gross notional forward sales, purchases and options transactions, locational basis swaps and other natural gas transactions. (b) Represents gross forward purchases associated with instruments used to hedge electricity price differences between settlement points within ERCOT. (c) Includes notional amounts of interest rate swaps with maturity dates through July 2023.
Credit risk-related contingent features of derivatives	The following table presents the commodity derivative liabilities subject to credit risk-related contingent features that are not fully collateralized: March 31, December 31, Fair value of derivative contract liabilities (a) $ (758 ) $ (204 ) Offsetting fair value under netting arrangements (b) 215 103 Cash collateral and letters of credit 336 41 Liquidity exposure $ (207 ) $ (60 ) ____________ (a) Excludes fair value of contracts that contain contingent features that do not provide specific amounts to be posted if features are triggered, including provisions that generally provide the right to request additional collateral (material adverse change, performance assurance and other clauses). (b) Amounts include the offsetting fair value of in-the-money derivative contracts and net accounts receivable under master netting arrangements.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of segment reporting information, by segment	. Three Months Ended March 31, 2018 2017 Operating revenues (a) Wholesale Generation $ (533 ) $ 785 Retail Electricity 972 865 Asset Closure 28 186 Corporate and Other — (1 ) Eliminations 298 (478 ) Consolidated operating revenues $ 765 $ 1,357 Depreciation and amortization Wholesale Generation $ (64 ) $ (53 ) Retail Electricity (76 ) $ (106 ) Corporate and Other (12 ) $ (11 ) Eliminations $ (1 ) $ — Consolidated depreciation and amortization $ (153 ) $ (170 ) Operating income (loss) Wholesale Generation $ (1,087 ) $ 300 Retail Electricity 757 $ (118 ) Asset Closure (23 ) $ (15 ) Corporate and Other (40 ) $ (12 ) Eliminations $ (1 ) $ — Consolidated operating income (loss) $ (394 ) $ 155 Net income (loss) Wholesale Generation $ (1,086 ) $ 303 Retail Electricity 771 (113 ) Asset Closure (22 ) (13 ) Corporate and Other 31 (99 ) Consolidated net income (loss) $ (306 ) $ 78 ____________ (a) For the three months ended March 31, 2018 and 2017 , includes third-party unrealized net gains (losses) from mark-to-market valuations of commodity positions of $(426) million and $126 million , respectively, recorded to the Wholesale Generation segment and $12 million and $8 million , respectively, recorded to the Retail Electricity segment. In addition, for the three months ended March 31, 2018 and 2017 , unrealized net gains (losses) with affiliate of $(643) million and $170 million , respectively, were recorded to operating revenues for the Wholesale Generation segment and corresponding unrealized net gains (losses) with affiliate of $643 million and $(170) million , respectively, were recorded to fuel, purchased power costs and delivery fees for the Retail Electricity segment, with no impact to consolidated results. March 31, December 31, 2017 Total assets Wholesale Generation $ 7,048 $ 6,834 Retail Electricity 6,890 6,156 Asset Closure 235 235 Corporate and Other and Eliminations 603 1,375 Consolidated total assets $ 14,776 $ 14,600

Supplementary Financial Infor38

Supplementary Financial Information (Tables)	3 Months Ended
	Mar. 31, 2018
Supplementary Financial Information [Abstract]
Schedule of interest expense and related charges	Interest Expense and Related Charges Three Months Ended March 31, 2018 2017 Interest paid/accrued $ 50 $ 54 Unrealized mark-to-market net gains on interest rate swaps (59 ) (9 ) Debt extinguishment gain — (21 ) Capitalized interest (3 ) (3 ) Other 3 3 Total interest expense and related charges $ (9 ) $ 24
Schedule of other income and deductions	Other Income and Deductions Three Months Ended March 31, 2018 2017 Other income: Office space sublease rental income (a) $ 2 $ 3 Mineral rights royalty income (b) — 1 Sale of land (b) 1 2 Interest income 6 1 All other 1 2 Total other income $ 10 $ 9 Other deductions: All other $ 2 $ — Total other deductions $ 2 $ — ____________ (a) Reported in Corporate and Other non-segment. (b) Reported in Wholesale Generation segment.
Schedule of restricted cash	Restricted Cash March 31, 2018 December 31, 2017 Current Noncurrent Assets Current Noncurrent Assets Amounts related to the Vistra Operations Credit Facilities (Note 10) $ — $ 500 $ — $ 500 Amounts related to restructuring escrow accounts 59 — 59 — Total restricted cash $ 59 $ 500 $ 59 $ 500
Schedule of accounts, notes, loans and financing receivable	Trade Accounts Receivable March 31, December 31, Wholesale and retail trade accounts receivable $ 477 $ 596 Allowance for uncollectible accounts (14 ) (14 ) Trade accounts receivable — net $ 463 $ 582 Gross trade accounts receivable at March 31, 2018 and December 31, 2017 included unbilled retail revenues of $187 million and $251 million , respectively. Allowance for Uncollectible Accounts Receivable Three Months Ended March 31, 2018 2017 Allowance for uncollectible accounts receivable at beginning of period $ 14 $ 10 Increase for bad debt expense 11 7 Decrease for account write-offs (11 ) (9 ) Allowance for uncollectible accounts receivable at end of period $ 14 $ 8
Schedule of inventories by major category	Inventories by Major Category March 31, December 31, Materials and supplies $ 149 $ 149 Fuel stock 62 83 Natural gas in storage 15 21 Total inventories $ 226 $ 253
Summary of other investments	Other Investments March 31, December 31, Nuclear plant decommissioning trust $ 1,180 $ 1,188 Land 49 49 Miscellaneous other 3 3 Total other investments $ 1,232 $ 1,240
Summary of investments in the fund	Nuclear Decommissioning Trust — Investments in a trust that will be used to fund the costs to decommission the Comanche Peak nuclear generation plant are carried at fair value. Decommissioning costs are being recovered from Oncor's customers as a delivery fee surcharge over the life of the plant and deposited by Vistra Energy in the trust fund. Income and expense associated with the trust fund and the decommissioning liability are offset by a corresponding change in a receivable/payable (currently a receivable reported in noncurrent assets) that will ultimately be settled through changes in Oncor's delivery fees rates. A summary of investments in the fund follows: March 31, 2018 Cost (a) Unrealized gain Unrealized loss Fair market value Debt securities (b) $ 425 $ 8 $ (6 ) $ 427 Equity securities (c) 268 487 (2 ) 753 Total $ 693 $ 495 $ (8 ) $ 1,180 December 31, 2017 Cost (a) Unrealized gain Unrealized loss Fair market value Debt securities (b) $ 418 $ 14 $ (2 ) $ 430 Equity securities (c) 265 495 (2 ) 758 Total $ 683 $ 509 $ (4 ) $ 1,188 ____________ (a) Includes realized gains and losses on securities sold. (b) The investment objective for debt securities is to invest in a diversified tax efficient portfolio with an overall portfolio rating of AA or above as graded by S&P or Aa2 by Moody's Investors Services, Inc. The debt securities are heavily weighted with government and municipal bonds and investment grade corporate bonds. The debt securities had an average coupon rate of 3.45% and 3.55% at March 31, 2018 and December 31, 2017 , respectively, and an average maturity of nine years at both March 31, 2018 and December 31, 2017 . (c) The investment objective for equity securities is to invest tax efficiently and to match the performance of the S&P 500 Index.
Summary of proceeds from sales of available-for-sale securities and the related realized gains and losses from such sales	The following table summarizes proceeds from sales of available-for-sale securities and the related realized gains and losses from such sales. Three Months Ended March 31, 2018 2017 Realized gains $ — $ 1 Realized losses $ (2 ) $ (2 ) Proceeds from sales of securities $ 46 $ 79 Investments in securities $ (51 ) $ (84 )
Schedule of asset retirement and mining reclamation obligations	The following table summarizes the changes to these obligations, reported as asset retirement obligations (current and noncurrent liabilities) in our condensed consolidated balance sheets, for the three months ended March 31, 2018 : Nuclear Plant Decommissioning Mining Land Reclamation Other Total Liability at December 31, 2017 $ 1,233 $ 438 $ 265 $ 1,936 Additions: Accretion 11 5 3 19 Adjustment for change in estimates — 4 — 4 Reductions: Payments — (16 ) — (16 ) Liability at March 31, 2018 1,244 431 268 1,943 Less amounts due currently — (117 ) (9 ) (126 ) Noncurrent liability at March 31, 2018 $ 1,244 $ 314 $ 259 $ 1,817
Schedule of other noncurrent liabilities and deferred credits	Other Noncurrent Liabilities and Deferred Credits The balance of other noncurrent liabilities and deferred credits consists of the following: March 31, December 31, Unfavorable purchase and sales contracts $ 32 $ 36 Other, including retirement and other employee benefits 207 220 Total other noncurrent liabilities and deferred credits $ 239 $ 256
Schedule of estimated amortization of unfavorable purchase and sales contracts [Table Text Block]	The estimated amortization of unfavorable purchase and sales contracts for each of the next five fiscal years is as follows: Year Amount 2018 $ 11 2019 $ 9 2020 $ 9 2021 $ 1 2022 $ 3
Schedule of fair value of debt	Fair Value of Debt March 31, 2018 December 31, 2017 Debt: Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt under the Vistra Operations Credit Facilities (Note 10) $ 4,313 $ 4,328 $ 4,323 $ 4,334 Other long-term debt, excluding capital lease obligations (Note 10) 27 24 30 27 Mandatorily redeemable subsidiary preferred stock (Note 10) 70 70 70 70
Schedule of cash, cash equivalents and restricted cash	The following table reconciles cash, cash equivalents and restricted cash reported in our condensed statements of consolidated cash flows to the amounts reported in our condensed balance sheets at March 31, 2018 and December 31, 2017 : March 31, December 31, Cash and cash equivalents $ 1,379 $ 1,487 Restricted cash included in current assets 59 59 Restricted cash included in noncurrent assets 500 500 Total cash, cash equivalents and restricted cash $ 1,938 $ 2,046
Schedule of supplemental cash flow information	The following table summarizes our supplemental cash flow information for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 2017 Cash payments related to: Interest paid $ 65 $ 89 Capitalized interest (3 ) (3 ) Interest paid (net of capitalized interest) $ 62 $ 86 Noncash investing and financing activities: Construction expenditures (a) $ 26 $ 1 ____________ (a) Represents end-of-period accruals for ongoing construction projects.

Business And Significant Acco39

Business And Significant Accounting Policies (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018Reportable_segment
Business and Significant Accounting Policies
Number of reportable segments (in reportable segments)	3

Business And Significant Acco40

Business And Significant Accounting Policies (Adoption of New Accounting Standards) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Assets [Abstract]
Prepaid expense and other current assets	$ 75		$ 77	$ 72
Accumulated deferred income taxes	793		706	710
Other noncurrent assets	189		178	162
Retained deficit	(1,700)		(1,393)	(1,410)
Income Statement [Abstract]
Revenues	765	$ 1,357
Selling, general and administrative expense	(162)	(135)
Net income (loss)	(306)	78
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (Decrease) in Restricted Cash		$ 1
Assets [Abstract]
Prepaid expense and other current assets	69			72
Accumulated deferred income taxes	797			710
Other noncurrent assets	169			162
Retained deficit	(1,720)			$ (1,410)
Income Statement [Abstract]
Revenues	764
Selling, general and administrative expense	(165)
Net income (loss)	(309)
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Assets [Abstract]
Prepaid expense and other current assets	6		5
Accumulated deferred income taxes	(4)		(4)
Other noncurrent assets	20		16
Retained deficit	20		$ 17
Income Statement [Abstract]
Revenues	1
Selling, general and administrative expense	3
Net income (loss)	$ 3

Merger Transaction (Merger Summ

Merger Transaction (Merger Summary) (Details)	Apr. 09, 2018USD ($)equity_unit$ / sharesshares	Apr. 30, 2018USD ($)	May 01, 2018	Mar. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)shares	Mar. 31, 2017shares	Dec. 31, 2016shares
Common Stock, Par or Stated Value Per Share | $ / shares				$ 0.01
Common stock, shares outstanding | shares				428,506,325	428,398,802	427,587,401	427,580,232
Long-Term Debt, Principal Amount Outstanding				$ 4,366,000,000	$ 4,379,000,000
Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues | shares	94,409,573
Common stock, shares outstanding | shares	522,932,453
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	9,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 35
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares	0.652
Merger Agreement, Common Stock Conversion Ratio | shares	0.652
Tangible Equity Units, Unit Price | equity_unit	100
Tangible Equity Units, Number Of Units Issued | shares	4,600,000
Business Combination, Preliminary Purchase Price	$ 2,300,000,000
Subsequent Event [Member] | Maximum [Member]
Prepaid Stock Purchase Contract, Number Of Common Shares Per Tangible Equity Unit | shares	4.0421
Subsequent Event [Member] | Minimum [Member]
Prepaid Stock Purchase Contract, Number Of Common Shares Per Tangible Equity Unit | shares	3.2731
Subsequent Event [Member] | Senior Notes [Member] | 6.75% Senior Notes Due 2019 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 850,000,000
Stated Interest Rate On Senior Notes	6.75%
Debt Instrument, Redemption Price			101.688%
Subsequent Event [Member] | Senior Notes [Member] | 7.375% Senior Notes Due 2022 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 1,750,000,000
Stated Interest Rate On Senior Notes	7.375%
Subsequent Event [Member] | Senior Notes [Member] | 5.875% Senior Notes Due 2023 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 500,000,000
Stated Interest Rate On Senior Notes	5.875%
Subsequent Event [Member] | Senior Notes [Member] | 7.625% Senior Notes Due 2024 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 1,250,000,000
Stated Interest Rate On Senior Notes	7.625%
Subsequent Event [Member] | Senior Notes [Member] | 8.034% Senior Notes Due 2024 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 188,000,000
Stated Interest Rate On Senior Notes	8.034%
Subsequent Event [Member] | Senior Notes [Member] | 8.000% Senior Notes Due 2025 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 750,000,000
Stated Interest Rate On Senior Notes	8.00%
Subsequent Event [Member] | Senior Notes [Member] | 8.125% Senior Notes Due 2026 [Member]
Long-Term Debt, Principal Amount Outstanding	$ 850,000,000
Stated Interest Rate On Senior Notes	8.125%
Subsequent Event [Member] | Amortizing Notes Due 2019 (Tangible Equity Units) [Member]
Long-Term Debt, Principal Amount Outstanding	$ 45,000,000
Debt Instrument, Periodic Payment	$ 1.7500
Stated Interest Rate On Senior Notes	7.00%
Subsequent Event [Member] | Vistra Energy Corp. [Member]
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01
Subsequent Event [Member] | Dynegy Inc. [Member]
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01
Subsequent Event [Member] | Dynegy Inc. [Member] | Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,563,000,000
Subsequent Event [Member] | Dynegy Inc. [Member] | Line of Credit [Member] | Senior Secured Term Loan [Member]
Line of Credit Facility, Maximum Borrowing Capacity	2,018,000,000
Subsequent Event [Member] | Dynegy Inc. [Member] | Line of Credit [Member] | Senior Secured Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	1,545,000,000
Line Of Credit Facility, Borrowings Outstanding	0
Line Of Credit Facility, Letters Of Credit Outstanding	$ 656,000,000
Repayments of Lines of Credit		$ 70,000,000

Acquisition and Development o42

Acquisition and Development of Generation Facilities (Odessa Acquisition) (Details) - Odessa-Ector Power Partners, L.P. [Member] - La Frontera Holdings, LLC [Member] $ in Millions	1 Months Ended
	Aug. 31, 2017USD ($)	Aug. 01, 2017Megawatt-hour
Electricity Generation Facility Capacity | Megawatt-hour		1,054
Purchase And Sale Agreement, Aggregate Purchase Price	$ 355
Earn-Out Period	5 years
Earn-Out Provision, Initial Fair Value Included In Purchase Price	$ 16

Acquisition and Development o43

Acquisition and Development of Generation Facilities (Upton Solar Development) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)Megawatt-hour	Mar. 31, 2017USD ($)
Solar development expenditures | $	$ 21	$ 0
Luminant Generation Company LLC [Member] | Upton County 2 Solar Facility [Member]
Electricity Generation Facility Capacity | Megawatt-hour	180

Retirement of Generation Fac44

Retirement of Generation Facilities (Retirement of Generation Facilities) (Details)	2 Months Ended
	Feb. 28, 2018Megawatt-hourpower_plant	Mar. 31, 2018Megawatt-hour
Number of power plants retired | power_plant	3
Electricity generation facility capacity retired	4,167	4,167
Number of electric generation units retired		7
Monticello Steam Electric Station [Member]
Electricity generation facility capacity retired		1,880
Number of electric generation units retired		3
Sandow Steam Electric Station Units 4 and 5 [Member]
Electricity generation facility capacity retired		1,137
Number of electric generation units retired		2
Big Brown Steam Electric Station [Member]
Electricity generation facility capacity retired		1,150
Number of electric generation units retired		2

Revenue (Narrative) (Details)

Revenue (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018
Residential Energy [Member]
Number Of Days Due From Invoice Date	20 days
Business Energy [Member] | Minimum [Member]
Number Of Days Due From Invoice Date	15 days
Business Energy [Member] | Maximum [Member]
Number Of Days Due From Invoice Date	45 days
Wholesale Generation Revenue From ERCOT [Member]
Number Of Days From Invoice Date Or Delivery To Cash Settlement	10 days
Revenue From Non-Affiliated REPs [Member]
Number Of Days From Invoice Date Or Delivery To Cash Settlement	20 days
Revenue From Other Wholesale Contracts [Member]
Number Of Days From Invoice Date Or Delivery To Cash Settlement	10 days

Revenue (Revenue Disaggregated

Revenue (Revenue Disaggregated By Major Source) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 1,212
Revenues	765	$ 1,357
Revenue From Oncor Service Area [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	662
Revenue From Other TDSP Service Areas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	287
Wholesale Generation Revenue From ERCOT [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	210
Revenue From Non-Affiliated REPs [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19
Revenue From Other Wholesale Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	34
Retail Contract Amortization [Member]
Disaggregation of Revenue [Line Items]
Revenues	(12)
Hedging And Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	(435)
Affiliate Sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Total Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	(447)
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Revenues	298	(478)
Intersegment Eliminations [Member] | Revenue From Oncor Service Area [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Intersegment Eliminations [Member] | Revenue From Other TDSP Service Areas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Intersegment Eliminations [Member] | Wholesale Generation Revenue From ERCOT [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Intersegment Eliminations [Member] | Revenue From Non-Affiliated REPs [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Intersegment Eliminations [Member] | Revenue From Other Wholesale Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Intersegment Eliminations [Member] | Retail Contract Amortization [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Intersegment Eliminations [Member] | Hedging And Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Intersegment Eliminations [Member] | Affiliate Sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	298
Intersegment Eliminations [Member] | Total Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	298
Retail Electricity Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	949
Revenues	972	865
Retail Electricity Segment [Member] | Revenue From Oncor Service Area [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	662
Retail Electricity Segment [Member] | Revenue From Other TDSP Service Areas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	287
Retail Electricity Segment [Member] | Wholesale Generation Revenue From ERCOT [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Retail Electricity Segment [Member] | Revenue From Non-Affiliated REPs [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Retail Electricity Segment [Member] | Revenue From Other Wholesale Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Retail Electricity Segment [Member] | Retail Contract Amortization [Member]
Disaggregation of Revenue [Line Items]
Revenues	(12)
Retail Electricity Segment [Member] | Hedging And Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	35
Retail Electricity Segment [Member] | Affiliate Sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Retail Electricity Segment [Member] | Total Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	23
Wholesale Generation Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	227
Revenues	(533)	785
Wholesale Generation Segment [Member] | Revenue From Oncor Service Area [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Wholesale Generation Segment [Member] | Revenue From Other TDSP Service Areas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Wholesale Generation Segment [Member] | Wholesale Generation Revenue From ERCOT [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	174
Wholesale Generation Segment [Member] | Revenue From Non-Affiliated REPs [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19
Wholesale Generation Segment [Member] | Revenue From Other Wholesale Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	34
Wholesale Generation Segment [Member] | Retail Contract Amortization [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Wholesale Generation Segment [Member] | Hedging And Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	(462)
Wholesale Generation Segment [Member] | Affiliate Sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	(298)
Wholesale Generation Segment [Member] | Total Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	(760)
Asset Closure Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36
Revenues	28	$ 186
Asset Closure Segment [Member] | Revenue From Oncor Service Area [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Asset Closure Segment [Member] | Revenue From Other TDSP Service Areas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Asset Closure Segment [Member] | Wholesale Generation Revenue From ERCOT [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36
Asset Closure Segment [Member] | Revenue From Non-Affiliated REPs [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Asset Closure Segment [Member] | Revenue From Other Wholesale Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Asset Closure Segment [Member] | Retail Contract Amortization [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Asset Closure Segment [Member] | Hedging And Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	(8)
Asset Closure Segment [Member] | Affiliate Sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	0
Asset Closure Segment [Member] | Total Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ (8)

Revenue (Contract and Other Cus

Revenue (Contract and Other Customer Acquisition Costs) (Details) - Costs To Acquire Residential And Business Retail Customers [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Jan. 01, 2018
Capitalized Contract Cost [Line Items]
Capitalized Contract Cost, Net	$ 27	$ 22
Selling, General and Administrative Expenses [Member]
Capitalized Contract Cost [Line Items]
Capitalized Contract Cost, Amortization	3
Operating Expense [Member]
Capitalized Contract Cost [Line Items]
Capitalized Contract Cost, Amortization	$ 1

Revenue (Accounts Receivable) (

Revenue (Accounts Receivable) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Trade accounts receivable — net	$ 463	$ 582
Trade Accounts Receivable From Contracts With Customers [Member]
Trade accounts receivable — net	415
Other Trade Accounts Receivables [Member]
Trade accounts receivable — net	$ 48

Goodwill and Identifiable Int49

Goodwill and Identifiable Intangible Assets (Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 1,907	$ 1,907
Retail Electricity Segment [Member]
Goodwill [Line Items]
Goodwill	1,907	$ 1,907
Goodwill, Expected Tax Deductible Amount	$ 1,686
Business Acquisition, Goodwill, Expected Tax Deductible Term	15 years

Goodwill and Identifiable Int50

Goodwill and Identifiable Intangible Assets (Identifiable Intangible Assets Reported in the Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	$ 2,021	$ 2,018
Accumulated Amortization	812	717
Total identifiable intangible assets subject to amortization, net	1,209	1,301
Total identifiable intangible assets	2,437	2,530
Retail trade names (not subject to amortization) [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount, Unamortized Intangibles	1,225	1,225
Mineral interests (not currently subject to amortization) [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount, Unamortized Intangibles	3	4
Retail customer relationship [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	1,648	1,648
Accumulated Amortization	645	572
Total identifiable intangible assets subject to amortization, net	1,003	1,076
Software and other technology-related assets [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	186	183
Accumulated Amortization	57	47
Total identifiable intangible assets subject to amortization, net	129	136
Retail and wholesale contracts [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	154	154
Accumulated Amortization	99	87
Total identifiable intangible assets subject to amortization, net	55	67
Other Identifiable Intangible Assets [Member]
Finite-Lived and Indefinite-Lived Intangible [Line Items]
Gross Carrying Amount	33	33
Accumulated Amortization	11	11
Total identifiable intangible assets subject to amortization, net	$ 22	$ 22

Goodwill and Identifiable Int51

Goodwill and Identifiable Intangible Assets (Amortization Expense Related to Identifiable Intangible Assets (including income statement line item)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 97	$ 145
Depreciation and amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	85	115
Retail customer relationship [Member] | Depreciation and amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	73	105
Software and other technology-related assets [Member] | Depreciation and amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	10	8
Retail and wholesale contracts [Member] | Operating revenues, fuel, purchased power costs and delivery fees [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	12	28
Other Identifiable Intangible Assets [Member] | Operating revenues, fuel, purchased power costs and delivery fees, depreciation and amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 2	$ 4

Goodwill and Identifiable Int52

Goodwill and Identifiable Intangible Assets (Estimated Amortization of Identifiable Intangible Assets) (Details) $ in Millions	Mar. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 368
2,019	268
2,020	192
2,021	142
2,022	$ 89

Income Taxes (Calculation of Ef

Income Taxes (Calculation of Effective Tax Rate)(Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income (loss) before income taxes	$ (395)	$ 119
Income tax benefit (expense)	$ 89	$ (41)
Effective tax rate	22.50%	34.50%
Effective tax rate at federal statutory rate	21.00%	35.00%

Tax Receivable Agreement Obli54

Tax Receivable Agreement Obligation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Percent of cash tax savings due Tax Receivable Agreement rights holders	85.00%
Effective tax rate at federal statutory rate	21.00%	35.00%
Estimated undiscounted future payments under Tax Receivable Agreement	$ 1,200
Impacts of tax receivable agreement	$ (18)	$ (21)

Tax Receivable Agreement Obli55

Tax Receivable Agreement Obligation (Summary of Tax Receivable Agreement Obligation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
TRA obligation at the beginning of the period	$ 357	$ 596
Accretion expense	18	21
TRA obligation at the end of the period	375	617
Less amounts due currently	(24)	(16)
Noncurrent TRA obligation at the end of the period	$ 351	$ 601	$ 333

Earnings Per Share (Earnings Pe

Earnings Per Share (Earnings Per Share)(Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income available for common stock — basic	$ (306)	$ 78
Weighted average shares of common stock outstanding - basic	428,450,384	427,583,339
Net income per weighted average share of common stock outstanding - basic	$ (0.71)	$ 0.18
Incremental common shares attributable to dilutive effect of share-based payment arrangements	0	217,011
Net income available for common stock — diluted	$ (306)	$ 78
Weighted average shares of common stock outstanding - diluted	428,450,384	427,800,350
Net income per weighted average share of common stock outstanding - diluted	$ (0.71)	$ 0.18
Antidilutive securities excluded from computation of earnings per share	2,863,872	602,403

Long-Term Debt (Long-Term Debt)

Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt, including amounts due currently	$ 4,410	$ 4,423
Long-term debt due currently	44	44
Long-term debt, less amounts due currently	4,366	4,379
Vistra Operations Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term debt, including amounts due currently	4,313	4,323
Debt instrument, unamortized premium	19	21
Debt instrument, unamortized discount	2	2
Unamortized debt issuance expense	6	7
PrefCo Mandatorily Redeemable Preferred Stock [Member] | Mandatorily Redeemable Preferred Stock [Member]
Debt Instrument [Line Items]
Long-term debt, including amounts due currently	70	70
Building Financing 8.82% due semiannually through February 11, 2022 [Member] | Construction Loans [Member]
Debt Instrument [Line Items]
Long-term debt, including amounts due currently	$ 27	$ 30
Debt instrument, interest rate, stated percentage	8.82%

Long-Term Debt (Vistra Operatio

Long-Term Debt (Vistra Operations Credit Facilities) (Details) - Vistra Operations Company LLC [Member] - Line of Credit [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 5,162
Line of Credit Facility, Maximum Borrowing Capacity	5,162
Line Of Credit Facility, Borrowings Outstanding	4,302
Line of Credit Facility, Remaining Borrowing Capacity	602
Senior Secured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	860
Line Of Credit Facility, Borrowings Outstanding	0
Line of Credit Facility, Remaining Borrowing Capacity	$ 584
Debt Instrument, Basis Spread on Variable Rate	2.25%
Senior Secured Revolving Credit Facility Letter Of Credit Sub-Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 715
Line Of Credit Facility, Letters Of Credit Outstanding	$ 276
Debt Instrument, Basis Spread on Variable Rate	2.25%
Senior Secured Initial Term Loan B And Senior Secured Term Loan C Facilities [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%
Senior Secured Initial Term Loan B Facility [Member] [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,814
Line Of Credit Facility, Borrowings Outstanding	2,814
Line of Credit Facility, Remaining Borrowing Capacity	$ 0
Line of Credit Facility, Interest Rate at Period End	4.38%
Senior Secured Incremental Term Loan B Facility [Member] [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 988
Line Of Credit Facility, Borrowings Outstanding	988
Line of Credit Facility, Remaining Borrowing Capacity	$ 0
Debt Instrument, Basis Spread on Variable Rate	2.25%
Line of Credit Facility, Interest Rate at Period End	4.07%
Senior Secured Term Loan C Facility [Member] [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 500
Line Of Credit Facility, Borrowings Outstanding	500
Line Of Credit Facility, Unused Letter Of Credit Capacity	18
Line Of Credit Facility, Letters Of Credit Outstanding	$ 482
Line of Credit Facility, Interest Rate at Period End	4.38%
Senior Secured Initial Term Loan B And Incremental Term Loan B Facilities [Member]
Line of Credit Facility [Line Items]
Line Of Credit Facility, Percentage Of Debt Required To Be Repaid Annually	1.00%
Minimum [Member] | Senior Secured Initial Term Loan B And Senior Secured Term Loan C Facilities [Member]
Line of Credit Facility [Line Items]
Debt instrument, interest rate, stated percentage	0.75%
Maximum [Member] | Senior Secured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Covenant, Outstanding Borrowings To Outstanding Commitments Threshold, Amount Of Letters Of Credit Excluded	$ 100
Debt Covenant, Outstanding Borrowings To Outstanding Commitments Threshold, Percent	30.00%
Debt Covenant, Net First Lien Debt To EBITDA Threshold	4.25

Long-Term Debt (Interest Rate S

Long-Term Debt (Interest Rate Swaps) (Details) - Interest rate swap [Member] - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivative Notional Amount	$ 3,000	$ 3,000
Minimum [Member]
Effective Interest Rate Debt Fixed Based On Derivative Contracts	4.38%
Maximum [Member]
Effective Interest Rate Debt Fixed Based On Derivative Contracts	4.50%

Commitments And Contingencies60

Commitments And Contingencies (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018USD ($)generating_unit
Pending Litigation [Member] | EPA Versus Luminant and Big Brown Power Company (Big Brown and Martin Lake Generation Facilities) [Member] | Minimum [Member]
Commitments and Contingencies [Line Items]
Loss Contingency Damages Sought Value Per Day	$ 32,500
Pending Litigation [Member] | EPA Versus Luminant and Big Brown Power Company (Big Brown and Martin Lake Generation Facilities) [Member] | Maximum [Member]
Commitments and Contingencies [Line Items]
Loss Contingency Damages Sought Value Per Day	$ 37,500
United States Environmental Protection Agency [Member]
Commitments and Contingencies [Line Items]
Clean Air Act, Regional Haze Program, Reasonable Progress Program, Number Of Units In Texas Subject To Upgrades to Existing Scrubbers | generating_unit	7
Clear Air Act, Regional Haze Program, Reasonable Progress Program, Number Of Units In Texas Subject To New Scrubbers | generating_unit	7
Clean Air Act, Regional Haze Program, Best Available Retrofit Technology Alternative, Sulfur Dioxide Emissions, Number of Unit In Texas Subject To Rule, Total	39
Luminant Generation Company LLC [Member] | United States Environmental Protection Agency [Member]
Commitments and Contingencies [Line Items]
Clean Air Act, Regional Haze Program, Best Available Retrofit Technology Alternative, Sulfur Dioxide Annual Emission Allowances Allocated To Units Covered By Program	91,222
Financial Standby Letter of Credit [Member] | Vistra Operations Company LLC [Member]
Commitments and Contingencies [Line Items]
Letters of Credit	$ 758,000,000
Support Risk Management And Trading Margin Requirements Including Over The Counter Hedging Transactions And Collateral Postings With Electric Reliability Council Of Texas [Member] | Financial Standby Letter of Credit [Member] | Vistra Operations Company LLC [Member]
Commitments and Contingencies [Line Items]
Letters of Credit	634,000,000
Support Executory Contracts And Insurance Agreements [Member] | Financial Standby Letter of Credit [Member] | Vistra Operations Company LLC [Member]
Commitments and Contingencies [Line Items]
Letters of Credit	36,000,000
Support Retail Electric Provider's financial requirements with the Public Utility Commission of Texas [Member] | Financial Standby Letter of Credit [Member] | Vistra Operations Company LLC [Member]
Commitments and Contingencies [Line Items]
Letters of Credit	55,000,000
Miscellaneous credit support requirements [Member] | Financial Standby Letter of Credit [Member] | Vistra Operations Company LLC [Member]
Commitments and Contingencies [Line Items]
Letters of Credit	$ 33,000,000

Equity (Narrative) (Details)

Equity (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries	$ 3,600
Equity
Common stock, shares authorized	1,800,000,000		1,800,000,000
Common stock, shares outstanding	428,506,325	428,398,802	427,587,401	427,580,232
Vistra Energy Corp. [Member] | Vistra Operations Company LLC [Member]
Debt Instrument [Line Items]
Maximum Allowable Distribution To Parent Company By Consolidated Subsidiary Without Consent	$ 975
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 0	$ 1,100

Equity (Changes to Equity) (Det

Equity (Changes to Equity) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 6,342	$ 6,597
Net income (loss)	(306)	78
Adoption of accounting standard	17
Effects of stock-based incentive compensation plans	7	4
Effects related to pension and other retirement benefit obligations (net of tax benefit of $— in all periods)	1	0
Other	(1)	1
Ending balance	6,060	6,680
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	4	4
Ending balance	4	4
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	7,765	7,742
Effects of stock-based incentive compensation plans	7	4
Ending balance	7,772	7,746
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,410)	(1,155)
Net income (loss)	(306)	78
Adoption of accounting standard	17
Other	(1)	1
Ending balance	(1,700)	(1,076)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(17)	6
Effects related to pension and other retirement benefit obligations (net of tax benefit of $— in all periods)	1
Ending balance	$ (16)	$ 6

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Assets:
Nuclear decommissioning trust	$ 1,180	$ 1,188
Equity Securities [Member]
Assets:
Nuclear decommissioning trust	753	758
Debt Securities [Member]
Assets:
Nuclear decommissioning trust	427	430
Fair Value, Measurements, Recurring [Member]
Assets:
Sub-total	7	10
Liabilities:
Total liabilities	7	10
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Assets:
Assets measured at net asset value	288	290
Fair Value, Measurements, Recurring [Member] | Commodity contracts [Member]
Assets:
Derivative Assets	7	2
Liabilities:
Derivative Liabilities	7	2
Fair Value, Measurements, Recurring [Member] | Interest rate swap [Member]
Assets:
Derivative Assets		8
Liabilities:
Derivative Liabilities		8
Fair Value, Measurements, Recurring [Member] | Total [Member]
Assets:
Sub-total	1,465	1,146
Total assets	1,753	1,436
Liabilities:
Total liabilities	981	326
Fair Value, Measurements, Recurring [Member] | Total [Member] | Equity Securities [Member]
Assets:
Nuclear decommissioning trust	465	468
Fair Value, Measurements, Recurring [Member] | Total [Member] | Debt Securities [Member]
Assets:
Nuclear decommissioning trust	427	430
Fair Value, Measurements, Recurring [Member] | Total [Member] | Commodity contracts [Member]
Assets:
Derivative Assets	496	222
Liabilities:
Derivative Liabilities	981	318
Fair Value, Measurements, Recurring [Member] | Total [Member] | Interest rate swap [Member]
Assets:
Derivative Assets	77	26
Liabilities:
Derivative Liabilities		8
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Sub-total	505	515
Liabilities:
Total liabilities	82	45
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Assets:
Nuclear decommissioning trust	465	468
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Commodity contracts [Member]
Assets:
Derivative Assets	40	47
Liabilities:
Derivative Liabilities	82	45
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Sub-total	790	546
Liabilities:
Total liabilities	505	143
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Assets:
Nuclear decommissioning trust	427	430
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Commodity contracts [Member]
Assets:
Derivative Assets	286	98
Liabilities:
Derivative Liabilities	505	143
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate swap [Member]
Assets:
Derivative Assets	77	18
Level 3 [Member]
Assets:
Sub-total	163	75
Liabilities:
Total liabilities	387	128
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Sub-total	163	75
Liabilities:
Total liabilities	387	128
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Commodity contracts [Member]
Assets:
Derivative Assets	163	75
Liabilities:
Derivative Liabilities	$ 387	$ 128

Fair Value Measurements (Sche64

Fair Value Measurements (Schedule of Fair Value of the Level 3 Assets and Liabilities by Major Contract Type (All Related to Commodity Contracts) and the Significant Unobservable Inputs Used in the Valuations) (Details) - Level 3 [Member] $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)$ / Megawatt-hour	Dec. 31, 2017USD ($)$ / Megawatt-hour
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets	$ 163	$ 75
Liabilities	(387)	(128)
Derivative Assets (Liabilities), at Fair Value, Net	(224)	(53)
Electricity purchases and sales [Member] | Valuation Model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets	41	12
Liabilities	(149)	(33)
Derivative Assets (Liabilities), at Fair Value, Net	(108)	(21)
Electricity and weather options [Member] | Option Pricing Model Valuation Technique [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets	41	10
Liabilities	(232)	(91)
Derivative Assets (Liabilities), at Fair Value, Net	(191)	(81)
Electricity congestion revenue rights [Member] | Market Approach [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets	66	45
Liabilities	(6)	(4)
Derivative Assets (Liabilities), at Fair Value, Net	60	41
Other [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets	15	8
Liabilities	0	0
Derivative Assets (Liabilities), at Fair Value, Net	$ 15	$ 8
Minimum [Member] | Electricity purchases and sales [Member] | Valuation Model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Hourly price curve shape (in usd per MWh) | $ / Megawatt-hour	0	0
Fair Value Inputs Illiquid Delivery Periods For ERCOT Hub Power Prices And Heat Rates | $ / Megawatt-hour	20	20
Minimum [Member] | Electricity and weather options [Member] | Option Pricing Model Valuation Technique [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Gas to power correlation	40.00%	30.00%
Fair Value Inputs, Power volatility	5.00%	5.00%
Minimum [Member] | Electricity congestion revenue rights [Member] | Market Approach [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Illiquid price differences between settlement points | $ / Megawatt-hour	0	0
Maximum [Member] | Electricity purchases and sales [Member] | Valuation Model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Hourly price curve shape (in usd per MWh) | $ / Megawatt-hour	60	40
Fair Value Inputs Illiquid Delivery Periods For ERCOT Hub Power Prices And Heat Rates | $ / Megawatt-hour	90	70
Maximum [Member] | Electricity and weather options [Member] | Option Pricing Model Valuation Technique [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Gas to power correlation	100.00%	100.00%
Fair Value Inputs, Power volatility	195.00%	180.00%
Maximum [Member] | Electricity congestion revenue rights [Member] | Market Approach [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Illiquid price differences between settlement points | $ / Megawatt-hour	15	15

Fair Value Measurements (Sche65

Fair Value Measurements (Schedule of Changes in Fair Value of the Level 3 Assets and Liabilities (All Related to Commodity Contracts)) (Details) - Level 3 [Member] - Commodity Contract [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net asset (liability) balance at beginning of period	$ (53)	$ 83
Total unrealized valuation gains (losses)	(213)	40
Purchases, issuances and settlements
Purchases	29	10
Issuances	(4)	(12)
Settlements	17	(19)
Transfers into Level 3	0	3
Transfers out of Level 3	0	2
Net change	(171)	24
Net asset (liability) balance at end of period	(224)	107
Unrealized valuation gains (losses) relating to instruments held at end of period	$ (206)	$ 36

Commodity and Other Derivativ66

Commodity and Other Derivative Contractual Assets and Liabilities (Financial Statement Effects of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 566	$ 238
Derivative liabilities, Fair Value, Gross Liability	(974)	(316)
Derivative, Fair Value, Net	(408)	(78)
Current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets And Liability, Fair Value, Gross Assets	404	190
Noncurrent assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets And Liability, Fair Value, Gross Assets	169	58
Current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets And Liability, Fair Value, Gross Liability	(595)	(224)
Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets And Liability, Fair Value, Gross Liability	(386)	(102)
Commodity contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	489	220
Derivative liabilities, Fair Value, Gross Liability	(974)	(316)
Derivative asset, Fair Value, Net	489	220
Derivative liabilities, Fair Value, Net	(974)	(316)
Commodity contracts [Member] | Current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	397	190
Derivative liabilities, Fair Value, Gross Asset	4	0
Commodity contracts [Member] | Noncurrent assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	95	30
Derivative liabilities, Fair Value, Gross Asset	0	2
Commodity contracts [Member] | Current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Fair Value, Gross Liability	(2)	0
Derivative liabilities, Fair Value, Gross Liability	(593)	(216)
Commodity contracts [Member] | Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Fair Value, Gross Liability	(1)	0
Derivative liabilities, Fair Value, Gross Liability	(385)	(102)
Interest rate swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	77	18
Derivative liabilities, Fair Value, Gross Liability	0	0
Derivative asset, Fair Value, Net	77	18
Derivative liabilities, Fair Value, Net	0	0
Interest rate swap [Member] | Current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3	0
Derivative liabilities, Fair Value, Gross Asset	0	0
Interest rate swap [Member] | Noncurrent assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	74	22
Derivative liabilities, Fair Value, Gross Asset	0	4
Interest rate swap [Member] | Current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Fair Value, Gross Liability	0	(4)
Derivative liabilities, Fair Value, Gross Liability	0	(4)
Interest rate swap [Member] | Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Fair Value, Gross Liability	0	0
Derivative liabilities, Fair Value, Gross Liability	$ 0	$ 0

Commodity and Other Derivativ67

Commodity and Other Derivative Contractual Assets and Liabilities (Derivative (Income Statement Presentation) and Derivative type (Income Statement Presentation of Loss Reclassified from Accumulated OCI into Income)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss)	$ (391)	$ 173
Operating revenues [Member] | Commodity contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss)	(446)	175
Fuel, purchased power costs and delivery fees [Member] | Commodity contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss)	(1)	(5)
Interest expense [Member] | Interest rate swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss)	$ 56	$ 3

Commodity and Other Derivativ68

Commodity and Other Derivative Contractual Assets and Liabilities (Derivative Assets and Liabilities From Balance Sheet to Net Amounts After Consideration Netting Arrangements with Counterparties and Financial Collateral) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets: Amounts Presented in Balance Sheet	$ 566	$ 238
Derivative assets: Offsetting Financial Instruments	(277)	(113)
Derivative assets: Financial Collateral (Received) Pledged	(1)	(1)
Derivative assets: Net Amounts	288	124
Derivative liabilities: Amounts Presented in Balance Sheet	(974)	(316)
Derivative liabilities: Offsetting Financial Instruments	277	113
Derivative liabilities: Financial Collateral (Received) Pledged	85	1
Derivative liabilities: Net Amounts	(612)	(202)
Derivative, Fair Value, Net	(408)	(78)
Derivative (Assets) Liability, Fair Value of Collateral, Net	84	0
Derivative Assets (Liability), Fair Value, Amount Offset Against Collateral	(324)	(78)
Commodity contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative assets: Amounts Presented in Balance Sheet	489	220
Derivative assets: Offsetting Financial Instruments	(277)	(113)
Derivative assets: Financial Collateral (Received) Pledged	(1)	(1)
Derivative assets: Net Amounts	211	106
Derivative liabilities: Amounts Presented in Balance Sheet	(974)	(316)
Derivative liabilities: Offsetting Financial Instruments	277	113
Derivative liabilities: Financial Collateral (Received) Pledged	85	1
Derivative liabilities: Net Amounts	(612)	(202)
Interest rate swap [Member]
Derivatives, Fair Value [Line Items]
Derivative assets: Amounts Presented in Balance Sheet	77	18
Derivative assets: Offsetting Financial Instruments	0	0
Derivative assets: Financial Collateral (Received) Pledged	0	0
Derivative assets: Net Amounts	77	18
Derivative liabilities: Amounts Presented in Balance Sheet	0	0
Derivative liabilities: Offsetting Financial Instruments	0	0
Derivative liabilities: Financial Collateral (Received) Pledged	0	0
Derivative liabilities: Net Amounts	$ 0	$ 0

Commodity and Other Derivativ69

Commodity and Other Derivative Contractual Assets and Liabilities (Derivative Volumes) (Details) lb in Thousands, gal in Millions, T in Millions, MMBTU in Millions, $ in Millions	Mar. 31, 2018USD ($)TgalMMBTUlbGWh	Dec. 31, 2017USD ($)TgalMMBTUlbGWh
Natural Gas Derivative [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume | MMBTU	1,423	1,259
Electricity (in GWh) [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume	102,316	114,129
Congestion Revenue RIghts (in GWh) [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume	142,560	110,913
Coal (in tons) [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume | T	2	2
Fuel oil (in gallons) [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume | gal	22	5
Uranium (in pounds) [Member]
Derivatives, Fair Value [Line Items]
Nonmonetary Notional Volume | lb	125	325
Interest rate swaps - Floating/fixed [Member]
Derivatives, Fair Value [Line Items]
Derivative Notional Amount | $	$ 3,000	$ 3,000

Commodity and Other Derivativ70

Commodity and Other Derivative Contractual Assets and Liabilities (Credit Risk-Related Contingent Features of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Credit Derivatives [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 758	$ 204
Credit risk derivative with contingent feature [Member]
Credit Derivatives [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	215	103
Collateral Already Posted, Aggregate Fair Value	336	41
Cross-default credit derivative [Member]
Credit Derivatives [Line Items]
Assets Needed for Immediate Settlement, Aggregate Fair Value	$ (207)	$ (60)

Commodity and Other Derivativ71

Commodity and Other Derivative Contractual Assets and Liabilities (Concentrations of Credit Risk Related to Derivatives) (Details) - Credit Risk Contract [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Derivative [Line Items]
Total credit risk exposure to all counterparties related to derivative contracts	$ 634
Net exposure to those counterparties after taking into effect master netting arrangements, setoff provisions and collateral	293
Largest net exposure to single counterparty	$ 77
Credit risk exposure to Banking and financial sector percentage	29.00%
Net exposure to banking and financial sector percentage	29.00%

Related Party Transactions (Nar

Related Party Transactions (Narrrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Maximum [Member]
Related Party Transaction [Line Items]
Registration Rights Agreement, Number Of Days To Convert S-1 Registration Statement To S-3 Registration Statement	30 days
Registration Rights Agreement, Demand Registration, Number Of Days To File S-1 Registration Statement	45 days
Registration Rights Agreement, Demand Registration, Number Of Days To File S-3 Registration Statement	30 days
Registration Rights Agreement, Demand Registration, Number Of Days Between Initial Registration And Effective Date	120 days
Legal Expenses Paid On Behalf of Selling Stockholders [Member]
Related Party Transaction [Line Items]
Legal Fees	$ 1	$ 1

Segment Information (Segment In

Segment Information (Segment Information) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)Reportable_segment	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments (in reportable segments) | Reportable_segment	3
Operating revenues	$ 765	$ 1,357
Depreciation and amortization	(153)	(170)
Operating income (loss)	(394)	155
Unrealized mark-to-market net losses on interest rate swaps	59	9
Net income (loss)	(306)	78
Net Income (Loss) Available to Common Stockholders, Basic	(306)	78
Total assets	14,776		$ 14,600
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	(1)
Depreciation and amortization	(12)	(11)
Operating income (loss)	(40)	(12)
Net Income (Loss) Available to Common Stockholders, Basic	31	(99)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	298	(478)
Depreciation and amortization	(1)	0
Operating income (loss)	(1)	0
Total assets	603		1,375
Wholesale Generation Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	(533)	785
Depreciation and amortization	(64)	(53)
Operating income (loss)	(1,087)	300
Net Income (Loss) Available to Common Stockholders, Basic	(1,086)	303
Wholesale Generation Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	7,048		6,834
Retail Electricity Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	972	865
Depreciation and amortization	(76)	(106)
Operating income (loss)	757	(118)
Net Income (Loss) Available to Common Stockholders, Basic	771	(113)
Retail Electricity Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	6,890		6,156
Asset Closure Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues	28	186
Operating income (loss)	(23)	(15)
Net Income (Loss) Available to Common Stockholders, Basic	(22)	(13)
Asset Closure Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	235		$ 235
Operating revenues [Member] | Wholesale Generation Segment [Member]
Segment Reporting Information [Line Items]
Unrealized mark-to-market net losses on interest rate swaps	(426)	126
Operating revenues [Member] | Wholesale Generation Segment [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Unrealized mark-to-market net losses on interest rate swaps	(643)	170
Operating revenues [Member] | Retail Electricity Segment [Member]
Segment Reporting Information [Line Items]
Unrealized mark-to-market net losses on interest rate swaps	12	8
Fuel, purchased power costs and delivery fees [Member] | Retail Electricity Segment [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Unrealized mark-to-market net losses on interest rate swaps	$ 643	$ (170)

Supplementary Financial Infor74

Supplementary Financial Information (Interest Expense and Related Charges) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest Expense and Related Charges [Line Items]
Interest paid/accrued	$ 50	$ 54
Unrealized Gain (Loss) on Derivatives	(59)	(9)
Gain (Loss) on Extinguishment of Debt	0	(21)
Interest Costs Capitalized Adjustment	(3)	(3)
Interest Expense, Other	3	3
Interest expense and related charges	$ (9)	$ 24
Vistra Operations Company LLC [Member] | Line of Credit [Member]
Interest Expense and Related Charges [Line Items]
Debt Instrument, Interest Rate During Period	4.43%

Supplementary Financial Infor75

Supplementary Financial Information (Other Income and Deductions) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other income:
Interest income	$ 6	$ 1
All other	1	2
Total other income	10	9
Other deductions:
All other	2	0
Total other deductions	2	0
Corporate and Other Nonsegment [Member]
Other income:
Office space sublease rental income	2	3
Wholesale Generation Segment [Member]
Other income:
Mineral rights royalty income (b)	0	1
Sale of land	$ 1	$ 2

Supplementary Financial Infor76

Supplementary Financial Information (Restricted Cash) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Restricted cash included in current assets	$ 59	$ 59
Restricted cash included in noncurrent assets	500	500
Vistra Operations Credit Facility [Member]
Restricted cash included in current assets	0	0
Restricted cash included in noncurrent assets	500	500
Amounts related to restructuring escrow accounts [Member]
Restricted cash included in current assets	59	59
Restricted cash included in noncurrent assets	$ 0	$ 0

Supplementary Financial Infor77

Supplementary Financial Information (Trade Accounts Receivable and Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Wholesale and retail trade accounts receivable			$ 477	$ 596
Allowance for uncollectible accounts	$ (14)	$ (10)	(14)	(14)
Trade accounts receivable — net			463	582
Unbilled Receivables, Current			$ 187	$ 251
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for uncollectible accounts receivable at beginning of period	14	10
Increase for bad debt expense	11	7
Decrease for account write-offs	(11)	(9)
Allowance for uncollectible accounts receivable at end of period	$ 14	$ 8

Supplementary Financial Infor78

Supplementary Financial Information (Inventories by Major Category and Other Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventories by Major Category
Materials and supplies	$ 149	$ 149
Fuel stock	62	83
Natural gas in storage	15	21
Total inventories	226	253
Other Investments
Nuclear plant decommissioning trust	1,180	1,188
Land	49	49
Miscellaneous other	3	3
Total other investments	$ 1,232	$ 1,240

Supplementary Financial Infor79

Supplementary Financial Information (Nuclear Decommissioning Trust) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2017
Schedule of Schedule of Decommissioning Fund Investments [Line Items]
Cost	$ 693			$ 683
Unrealized gain	495			509
Unrealized loss	(8)			(4)
Fair market value	1,180			1,188
Realized gains	0	$ 1
Realized losses	(2)	(2)
Proceeds from sales of securities	46	79
Investments in securities	(51)	$ (84)
Debt Securities [Member]
Schedule of Schedule of Decommissioning Fund Investments [Line Items]
Cost	425			418
Unrealized gain	8			14
Unrealized loss	(6)			(2)
Fair market value	$ 427			$ 430
Debt, Weighted Average Interest Rate	3.45%			3.55%
Decommissioning Fund Investments, Debt securities, average maturity	9 years		9 years
Decommissioning Fund Investments, debt maturities, one through five years, fair value	$ 133
Decommissioning Fund Investments, debt maturities, five through ten years, fair value	91
Decommissioning Fund Investments, debt maturities, after ten years, fair value	203
Equity Securities [Member]
Schedule of Schedule of Decommissioning Fund Investments [Line Items]
Cost	268			$ 265
Unrealized gain	487			495
Unrealized loss	(2)			(2)
Fair market value	$ 753			$ 758

Supplementary Financial Infor80

Supplementary Financial Information (Property, Plant and Equipment) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Property, plant and equipment — net	$ 4,850	$ 4,820
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 480	$ 393

Supplementary Financial Infor81

Supplementary Financial Information (Asset Retirement and Mining Reclamation Obligations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance, Liability	$ 1,936
Additions:
Accretion	19	$ 14
Reductions:
Payments	(16)
Ending balance, Liability	1,936		$ 1,943	$ 1,936
Less amounts due currently			(126)	(99)
Noncurrent liability at end of period	1,817
Asset Retirement Obligation, Adjustment For New Cost Estimate	4
Nuclear Plant Decommissioning [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets			64
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance, Liability	1,233
Additions:
Accretion	11
Reductions:
Payments	0
Ending balance, Liability	1,233		1,244	1,233
Less amounts due currently			0
Noncurrent liability at end of period	1,244
Asset Retirement Obligation, Adjustment For New Cost Estimate	0
Mining Land Reclamation [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance, Liability	438
Additions:
Accretion	5
Reductions:
Payments	(16)
Ending balance, Liability	438		431	438
Less amounts due currently			(117)
Noncurrent liability at end of period	314
Asset Retirement Obligation, Adjustment For New Cost Estimate	4
Other Asset Retirement Obligations [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance, Liability	265
Additions:
Accretion	3
Reductions:
Payments	0
Ending balance, Liability	265		268	$ 265
Less amounts due currently			$ (9)
Noncurrent liability at end of period	259
Asset Retirement Obligation, Adjustment For New Cost Estimate	$ 0

Supplementary Financial Infor82

Supplementary Financial Information (Other Noncurrent Liabilities and Deferred Credits) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Unfavorable purchase and sales contracts	$ 32		$ 36
Other, including retirement and other employee benefits	207		220
Total other noncurrent liabilities and deferred credits	239		$ 256
Amortization of Deferred Charges [Abstract]
Amortization of Unfavorable Purchase and Sales Contracts	4	$ 3
Future Amortization Expense, Unfavorable Purchase and Sales Contracts [Abstract]
2,018	11
2,019	9
2,020	9
2,021	1
2,022	$ 3

Supplementary Financial Infor83

Supplementary Financial Information (Fair Value of Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Vistra Operations Credit Facility [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	$ 4,313	$ 4,323
Long-Term Debt, Including Amounts Due Currently [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	27	30
Mandatorily Redeemable Preferred Stock [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	70	70
Fair Value, Inputs, Level 2 [Member] | Vistra Operations Credit Facility [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	4,328	4,334
Fair Value, Inputs, Level 2 [Member] | Long-Term Debt, Including Amounts Due Currently [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	24	27
Fair Value, Inputs, Level 2 [Member] | Mandatorily Redeemable Preferred Stock [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Fair Value Disclosure	$ 70	$ 70

Supplementary Financial Infor84

Supplementary Financial Information (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Cash and cash equivalents	$ 1,379		$ 1,487
Restricted cash included in current assets	59		59
Restricted cash included in noncurrent assets	500		500
Total cash, cash equivalents and restricted cash	1,938	$ 1,660	$ 2,046	$ 1,588
Cash payments related to:
Interest paid	65	89
Capitalized interest	(3)	(3)
Interest paid (net of capitalized interest)	62	86
Noncash investing and financing activities:
Construction expenditures	$ 26	$ 1