v3.8.0.1

Assets and Liabilities with Recurring Fair Value Measurements (Tables) | 9 Months Ended
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Sep. 30, 2017
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |
Fair Value, Measurement Inputs, Disclosure | The following tables present our financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2017 and December 31, 2016, by level within the fair value hierarchy:
| Assets and Liabilities with Recurring Fair Value Measures as of September 30, 2017
| Level 1 |  | Level 2 |  | Level 3 |  | Total
| (in millions)
Assets: |  |  |  |  |  |  |
Cash equivalents(1) | $ | 173 |  |  | $ | — |  |  | $ | — |  |  | $ | 173 |
Commodity instruments: |  |  |  |  |  |  |
Commodity exchange traded futures and swaps contracts | 605 |  |  | — |  |  | — |  |  | 605 |
Commodity forward contracts(2) | — |  |  | 362 |  |  | 332 |  |  | 694 |
Interest rate hedging instruments | — |  |  | 20 |  |  | — |  |  | 20 |
Effect of netting and allocation of collateral(3)(4) | (605 | ) |  | (203 | ) |  | (21 | ) |  | (829 | )
Total assets | $ | 173 |  |  | $ | 179 |  |  | $ | 311 |  |  | $ | 663 |
Liabilities: |  |  |  |  |  |  |
Commodity instruments: |  |  |  |  |  |  |
Commodity exchange traded futures and swaps contracts | 656 |  |  | — |  |  | — |  |  | 656 |
Commodity forward contracts(2) | — |  |  | 355 |  |  | 64 |  |  | 419 |
Interest rate hedging instruments | — |  |  | 52 |  |  | — |  |  | 52 |
Effect of netting and allocation of collateral(3)(4) | (656 | ) |  | (220 | ) |  | (35 | ) |  | (911 | )
Total liabilities | $ | — |  |  | $ | 187 |  |  | $ | 29 |  |  | $ | 216 |
| Assets and Liabilities with Recurring Fair Value Measures as of December 31, 2016
| Level 1 |  | Level 2 |  | Level 3 |  | Total
| (in millions)
Assets: |  |  |  |  |  |  |
Cash equivalents(1) | $ | 153 |  |  | $ | — |  |  | $ | — |  |  | $ | 153 |
Commodity instruments: |  |  |  |  |  |  |
Commodity exchange traded futures and swaps contracts | 1,542 |  |  | — |  |  | — |  |  | 1,542 |
Commodity forward contracts(2) | — |  |  | 231 |  |  | 466 |  |  | 697 |
Interest rate hedging instruments | — |  |  | 29 |  |  | — |  |  | 29 |
Effect of netting and allocation of collateral(3)(4) | (1,542 | ) |  | $ | (188 | ) |  | (17 | ) |  | (1,747 | )
Total assets | $ | 153 |  |  | $ | 72 |  |  | $ | 449 |  |  | $ | 674 |
Liabilities: |  |  |  |  |  |  |
Commodity instruments: |  |  |  |  |  |  |
Commodity exchange traded futures and swaps contracts | 1,570 |  |  | — |  |  | — |  |  | 1,570 |
Commodity forward contracts(2) | — |  |  | 411 |  |  | 67 |  |  | 478 |
Interest rate hedging instruments | — |  |  | 58 |  |  | — |  |  | 58 |
Effect of netting and allocation of collateral(3)(4) | (1,570 | ) |  | $ | (215 | ) |  | (34 | ) |  | (1,819 | )
Total liabilities | $ | — |  |  | $ | 254 |  |  | $ | 33 |  |  | $ | 287 |
___________
(1) | At September 30, 2017 and December 31, 2016, we had cash equivalents of $32 million and $26 million included in cash and cash equivalents and $141 million and $127 million included in restricted cash, respectively.
(2) | Includes OTC swaps and options and retail contracts.
(3) | During the third quarter of 2017, we elected to offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation; therefore, amounts recognized for the right to reclaim, or the obligation to return, cash collateral are presented net with the corresponding derivative instrument fair values. See Note 1 for a further description of the change in accounting principle associated with our election to offset fair value amounts associated with our derivative instruments. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.
(4) | Cash collateral posted with (received from) counterparties allocated to level 1, level 2 and level 3 derivative instruments totaled $51 million, $17 million and $14 million, respectively, at September 30, 2017. Cash collateral posted with (received from) counterparties allocated to level 1, level 2 and level 3 derivative instruments totaled $28 million, $27 million and $17 million, respectively, at December 31, 2016.
Fair Value Inputs, Assets, Quantitative Information | The following table presents quantitative information for the unobservable inputs used in our most significant level 3 fair value measurements at September 30, 2017 and December 31, 2016:
|  | Quantitative Information about Level 3 Fair Value Measurements |
|  | September 30, 2017 |
|  | Fair Value, Net Asset |  |  |  | Significant Unobservable |  |  |  |  |
|  | (Liability) |  | Valuation Technique |  | Input |  | Range
|  | (in millions) |  |  |  |  |  |  |  |  |
Power Contracts |  | $ | 234 |  |  | Discounted cash flow |  | Market price (per MWh) |  | $ | 6.55 |  | — | $89.83 | /MWh
Power Congestion Products |  | $ | 10 |  |  | Discounted cash flow |  | Market price (per MWh) |  | $ | (13.13 | ) | — | $6.85 | /MWh
Natural Gas Contracts |  | $ | 38 |  |  | Discounted cash flow |  | Market price (per MMBtu) |  | $ | 0.97 |  | — | $9.35 | /MMBtu
|  | December 31, 2016 |
|  | Fair Value, Net Asset |  |  |  | Significant Unobservable |  |  |  |  |
|  | (Liability) |  | Valuation Technique |  | Input |  | Range
|  | (in millions) |  |  |  |  |  |  |  |  |
Power Contracts |  | $ | 376 |  |  | Discounted cash flow |  | Market price (per MWh) |  | $ | 9.60 |  | — | $86.34 | /MWh
Power Congestion Products |  | $ | 12 |  |  | Discounted cash flow |  | Market price (per MWh) |  | $ | (7.52 | ) | — | $13.62 | /MWh
Natural Gas Contracts |  | $ | 18 |  |  | Discounted cash flow |  | Market price (per MMBtu) |  | $ | 1.95 |  | — | $5.66 | /MMBtu
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] | The following table sets forth a reconciliation of changes in the fair value of our net derivative assets (liabilities) classified as level 3 in the fair value hierarchy for the periods indicated (in millions):
|  | Three Months Ended September 30, |  | Nine Months Ended September 30,
|  | 2017 |  | 2016 |  | 2017 |  | 2016
Balance, beginning of period |  | $ | 303 |  |  | $ | (61 | ) |  | $ | 416 |  |  | $ | (46 | )
Realized and mark-to-market gains (losses): |  |  |  |  |  |  |  |
Included in net loss: |  |  |  |  |  |  |  |
Included in operating revenues(1) |  | 26 |  |  | 30 |  |  | 125 |  |  | 9 |
Included in fuel and purchased energy expense(2) |  | (12 | ) |  | (31 | ) |  | (1 | ) |  | (24 | )
Change in collateral |  | 4 |  |  | (2 | ) |  | (4 | ) |  | — |
Purchases and settlements: |  |  |  |  |  |  |  |
Purchases |  | 1 |  |  | 1 |  |  | 2 |  |  | 4 |
Settlements |  | (40 | ) |  | 15 |  |  | (129 | ) |  | (4 | )
Transfers in and/or out of level 3(3): |  |  |  |  |  |  |  |
Transfers into level 3(4) |  | 3 |  |  | 1 |  |  | (5 | ) |  | — |
Transfers out of level 3(5) |  | (3 | ) |  | 75 |  |  | (122 | ) |  | 89 |
Balance, end of period |  | $ | 282 |  |  | $ | 28 |  |  | $ | 282 |  |  | $ | 28 |
Change in unrealized gains (losses) relating to instruments still held at end of period |  | $ | 14 |  |  | $ | (1 | ) |  | $ | 124 |  |  | $ | (15 | )
___________
(1) | For power contracts and other power-related products, included on our Consolidated Condensed Statements of Operations.
(2) | For natural gas and power contracts, swaps and options, included on our Consolidated Condensed Statements of Operations.
(3) | We transfer amounts among levels of the fair value hierarchy as of the end of each period. There were no transfers into or out of level 1 for each of the three and nine months ended September 30, 2017 and 2016.
(4) | There were $3 million and $1 million in gains transferred out of level 2 into level 3 for the three months ended September 30, 2017 and 2016, and $(5) million and nil in losses transferred out of level 2 into level 3 for the nine months ended September 30, 2017 and 2016, respectively, due to changes in market liquidity in various power markets.
(5) | We had $3 million in gains and $(75) million in losses transferred out of level 3 into level 2 for the three months ended September 30, 2017 and 2016, respectively, and $122 million in gains and $(89) million in losses transferred out of level 3 into level 2 for the nine months ended September 30, 2017 and 2016, respectively, due to changes in market liquidity in various power markets.

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- Definition Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19279-110258 + Details
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- Definition Tabular disclosure of quantitative information about the inputs used in the fair value measurement of assets. This disclosure may include, but is not limited to, the fair value of the asset, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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