Calpine (CPNLQ) 10-Q 1 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 28, 2014
Entity Information [Line Items]	'	'
Entity Registrant Name	'CALPINE CORP	'
Entity Central Index Key	'0000916457	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	423,378,759

Consolidated_Condensed_Stateme

Consolidated Condensed Statements of Operations (USD $)	3 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating revenues:	'	'
Commodity revenue	$2,048	$1,308
Unrealized mark-to-market (loss)	-86	-71
Other revenue	3	4
Operating revenues	1,965	1,241
Operating expenses:	'	'
Commodity expense	1,370	835
Unrealized mark-to-market (gain)	-13	-14
Fuel and purchased energy expense	1,357	821
Plant operating expense	265	227
Depreciation and amortization expense	153	146
Sales, general and other administrative expense	33	33
Other operating expenses	22	18
Total operating expenses	1,830	1,245
(Income) from unconsolidated investments in power plants	-9	-8
Income from operations	144	4
Interest expense	166	176
Interest (income)	-1	-2
Other (income) expense, net	11	5
Loss before income taxes	-32	-175
Income tax benefit	-19	-50
Net loss	-13	-125
Net income attributable to the noncontrolling interest	-4	0
Net loss attributable to Calpine	($17)	($125)
Weighted Average Number of Shares Outstanding, Basic and Diluted	420,105	451,706
Earnings Per Share, Basic and Diluted	($0.04)	($0.28)

Consolidated_Condensed_Stateme1

Consolidated Condensed Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'	'
Net loss	($13)	($125)
Cash flow hedging activities:	'	'
Gain (loss) on cash flow hedges before reclassification adjustment for cash flow hedges realized in net loss	-13	4
Reclassification adjustment for loss on cash flow hedges realized in net loss	13	9
Foreign currency translation loss	-6	-2
Income tax benefit	0	1
Other comprehensive income (loss)	-6	12
Comprehensive loss	-19	-113
Comprehensive (income) attributable to the noncontrolling interest	-4	-1
Comprehensive loss attributable to Calpine	($23)	($114)

Consolidated_Condensed_Balance

Consolidated Condensed Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents ($70 and $242 attributable to VIEs)	$515	$941
Accounts receivable, net of allowance of $5 and $5	627	552
Margin deposits and other prepaid expense	293	309
Restricted cash, current ($115 and $100 attributable to VIEs)	195	203
Derivative assets, current	655	445
Inventory and other current assets	417	406
Total current assets	2,702	2,856
Property, plant and equipment, net ($4,568 and $4,191 attributable to VIEs)	13,598	12,995
Restricted cash, net of current portion ($70 and $68 attributable to VIEs)	71	69
Investments in power plants	85	93
Long-term derivative assets	174	105
Other assets	437	441
Total assets	17,067	16,559
Current liabilities:	'	'
Accounts payable	607	462
Accrued interest payable	93	162
Debt, current portion ($129 and $140 attributable to VIEs)	189	204
Derivative liabilities, current	728	451
Other current liabilities	256	252
Total current liabilities	1,873	1,531
Debt, net of current portion ($3,322 and $2,923 attributable to VIEs)	11,286	10,908
Long-term derivative liabilities	230	243
Other long-term liabilities	266	309
Total liabilities	13,655	12,991
Commitments and contingencies (see Note 11)	'	'
Stockholders’ equity:	'	'
Preferred stock, $0.001 par value per share; authorized 100,000,000 shares, none issued and outstanding	0	0
Common stock, $0.001 par value per share; authorized 1,400,000,000 shares, 499,765,622 and 497,841,056 shares issued, respectively, and 423,242,107 and 429,038,988 shares outstanding, respectively	1	1
Treasury stock, at cost, 76,523,515 and 68,802,068 shares, respectively	-1,378	-1,230
Additional paid-in capital	12,400	12,389
Accumulated deficit	-7,503	-7,486
Accumulated other comprehensive loss	-166	-160
Total Calpine stockholders’ equity	3,354	3,514
Noncontrolling interest	58	54
Total stockholders’ equity	3,412	3,568
Total liabilities and stockholders’ equity	$17,067	$16,559

Consolidated_Condensed_Balance1

Consolidated Condensed Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Cash and cash equivalents ($70 and $242 attributable to VIEs)	$515	$941
Allowance for Doubtful Accounts Receivable, Current	5	5
Restricted cash, current ($115 and $100 attributable to VIEs)	195	203
Property, plant and equipment, net ($4,568 and $4,191 attributable to VIEs)	13,598	12,995
Restricted cash, net of current portion ($70 and $68 attributable to VIEs)	71	69
Debt, current portion ($129 and $140 attributable to VIEs)	189	204
Debt, net of current portion ($3,322 and $2,923 attributable to VIEs)	11,286	10,908
Preferred Stock, Par or Stated Value Per Share	$0.00	$0.00
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$0.00	$0.00
Common Stock, Shares Authorized	1,400,000,000	1,400,000,000
Common Stock, Shares, Issued	499,765,622	497,841,056
Common Stock, Shares, Outstanding	423,242,107	429,038,988
Treasury Stock, Shares	76,523,515	68,802,068
Variable Interest Entity, Primary Beneficiary [Member]	'	'
Cash and cash equivalents ($70 and $242 attributable to VIEs)	70	242
Restricted cash, current ($115 and $100 attributable to VIEs)	115	100
Property, plant and equipment, net ($4,568 and $4,191 attributable to VIEs)	4,568	4,191
Restricted cash, net of current portion ($70 and $68 attributable to VIEs)	70	68
Debt, current portion ($129 and $140 attributable to VIEs)	129	140
Debt, net of current portion ($3,322 and $2,923 attributable to VIEs)	$3,322	$2,923

Consolidated_Condensed_Stateme2

Consolidated Condensed Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Cash flows from operating activities:	'		'
Net loss	($13)		($125)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:	'		'
Depreciation and amortization expense(1)	164	[1]	158	[1]
Deferred income taxes	-13		-7
Unrealized mark-to-market activity, net	72	[2]	55	[2]
(Income) from unconsolidated investments in power plants	-9		-8
Return on unconsolidated investments in power plants	13		0
Stock-based compensation expense	10		8
Other	-2		0
Change in operating assets and liabilities:	'		'
Accounts receivable	-75		-45
Derivative instruments, net	-87		-36
Other assets	29		-73
Accounts payable and accrued expenses	106		-91
Other liabilities	-72		7
Net cash provided by (used in) operating activities	123		-157
Cash flows from investing activities:	'		'
Purchases of property, plant and equipment	-119		-176
Purchase of Guadalupe Power Plant, net of cash	-656		0
Decrease in restricted cash	6		54
Net cash used in investing activities	-769		-122
Cash flows from financing activities:	'		'
Borrowings under CCFC Term Loans	420		0
Repayments of Debt	-11		-6
Borrowings from project financing, notes payable and other	1		73
Repayments of project financing, notes payable and other	-43		-36
Financing costs	-10		-9
Stock repurchases	-140		-75
Proceeds from exercises of stock options	3		9
Other	0		1
Net cash provided by (used in) financing activities	220		-43
Net decrease in cash and cash equivalents	-426		-322
Cash and cash equivalents, beginning of period	941		1,284
Cash and cash equivalents, end of period	515		962
Cash paid during the period for:	'		'
Interest, net of amounts capitalized	225		213
Income taxes	8		5
Supplemental disclosure of non-cash investing activities:	'		'
Change in capital expenditures included in accounts payable	($9)		$17
[1]	Includes depreciation and amortization included in fuel and purchased energy expense and interest expense on our Consolidated Condensed Statements of Operations
[2]	In addition to changes in market value on derivatives not designated as hedges, changes in unrealized gain (loss) also includes de-designation of interest rate swap cash flow hedges and related reclassification from AOCI into earnings, hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Basis of Presentation and Summary of Significant Accounting Policies
	We are a wholesale power generation company engaged in the ownership and operation of primarily natural gas-fired and geothermal power plants in North America. We have a significant presence in major competitive wholesale power markets in California, Texas and the Mid-Atlantic region of the U.S. We sell wholesale power, steam, capacity, renewable energy credits and ancillary services to our customers, which include utilities, independent electric system operators, industrial and agricultural companies, retail power providers, municipalities, power marketers and others. We purchase primarily natural gas and some fuel oil as fuel for our power plants and engage in related natural gas transportation and storage transactions. We purchase electric transmission rights to deliver power to our customers. Additionally, consistent with our Risk Management Policy, we enter into natural gas and power physical and financial contracts to hedge certain business risks and optimize our portfolio of power plants.
	Basis of Interim Presentation — The accompanying unaudited, interim Consolidated Condensed Financial Statements of Calpine Corporation, a Delaware corporation, and consolidated subsidiaries have been prepared pursuant to the rules and regulations of the SEC. In the opinion of management, the Consolidated Condensed Financial Statements include the normal, recurring adjustments necessary for a fair statement of the information required to be set forth therein. Certain information and note disclosures, normally included in financial statements prepared in accordance with U.S. GAAP, have been condensed or omitted from these statements pursuant to such rules and regulations and, accordingly, these financial statements should be read in conjunction with our audited Consolidated Financial Statements for the year ended December 31, 2013, included in our 2013 Form 10-K. The results for interim periods are not necessarily indicative of the results for the entire year primarily due to acquisitions and disposals of assets, seasonal fluctuations in our revenues, timing of major maintenance expense, variations resulting from the application of the method to calculate the provision for income tax for interim periods, volatility of commodity prices and unrealized gains and losses from commodity and interest rate derivative contracts.
	Use of Estimates in Preparation of Financial Statements — The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures included in our Consolidated Condensed Financial Statements. Actual results could differ from those estimates.
	Reclassifications — We have reclassified certain prior year amounts for comparative purposes. These reclassifications did not have a material impact on our financial condition, results of operations or cash flows.
	Cash and Cash Equivalents — We consider all highly liquid investments with an original maturity of three months or less to be cash equivalents. We have certain project finance facilities and lease agreements that require us to establish and maintain segregated cash accounts, which have been pledged as security in favor of the lenders under such project finance facilities, and the use of certain cash balances on deposit in such accounts is limited, at least temporarily, to the operations of the respective projects. At March 31, 2014 and December 31, 2013, we had cash and cash equivalents of $98 million and $292 million, respectively, that were subject to such project finance facilities and lease agreements.
	Restricted Cash — Certain of our debt agreements, lease agreements or other operating agreements require us to establish and maintain segregated cash accounts, the use of which is restricted. These amounts are held by depository banks in order to comply with the contractual provisions requiring reserves for payments such as for debt service, rent, major maintenance and debt repurchases or with applicable regulatory requirements. Funds that can be used to satisfy obligations due during the next 12 months are classified as current restricted cash, with the remainder classified as non-current restricted cash. Restricted cash is generally invested in accounts earning market rates; therefore, the carrying value approximates fair value. Such cash is excluded from cash and cash equivalents on our Consolidated Condensed Balance Sheets and Statements of Cash Flows.
	The table below represents the components of our restricted cash as of March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014						December 31, 2013
		Current		Non-Current		Total		Current		Non-Current		Total
	Debt service(1)	$	11	$	41	$	52	$	11	$	41	$	52
	Rent reserve	4		—		4		3		—		3
	Construction/major maintenance	34		22		56		35		20		55
	Security/project/insurance	146		6		152		151		6		157
	Other	—		2		2		3		2		5
	Total	$	195	$	71	$	266	$	203	$	69	$	272
	___________
	-1	At both March 31, 2014 and December 31, 2013, amounts restricted for debt service included approximately $24 million of repurchase agreements with a financial institution containing maturity dates greater than one year.
	Inventory — At March 31, 2014 and December 31, 2013, we had inventory of $361 million and $364 million, respectively. Inventory primarily consists of spare parts, stored natural gas and fuel oil, environmental products and natural gas exchange imbalances. Inventory, other than spare parts, is stated primarily at the lower of cost or market value under the weighted average cost method. Spare parts inventory is valued at weighted average cost and is expensed to plant operating expense or capitalized to property, plant and equipment as the parts are utilized and consumed.
	Property, Plant and Equipment, Net — At March 31, 2014 and December 31, 2013, the components of property, plant and equipment are stated at cost less accumulated depreciation as follows (in millions):
		March 31, 2014		31-Dec-13		Depreciable Lives
	Buildings, machinery and equipment(1)	$	16,516	$	15,838	3 – 47 Years
	Geothermal properties	1,267		1,265		13 – 59 Years
	Other	167		164		3 – 47 Years
		17,950		17,267
	Less: Accumulated depreciation	5,046		4,897
		12,904		12,370
	Land	109		103
	Construction in progress	585		522
	Property, plant and equipment, net	$	13,598	$	12,995
	___________
	-1	The change from December 31, 2013 to March 31, 2014 can primarily be attributed to our acquisition of Guadalupe Energy Center on February 26, 2014.
	Capitalized Interest — The total amount of interest capitalized was $6 million and $12 million for the three months ended March 31, 2014 and 2013, respectively.
	Treasury Stock — During the three months ended March 31, 2014, we repurchased common stock with a value of $140 million and withheld shares with a value of $8 million to satisfy tax withholding obligations associated with the vesting of restricted stock awarded to employees and net share employee stock options exercises under the Equity Plan.
	New Accounting Standards and Disclosure Requirements
	Income Taxes — In July 2013, the FASB issued Accounting Standards Update 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists”. The provisions of the rule require an unrecognized tax benefit to be presented as a reduction to a deferred tax asset in the financial statements for an NOL carryforward, a similar tax loss, or a tax credit carryforward except in circumstances when the carryforward or tax loss is not available at the reporting date under the tax laws of the applicable jurisdiction to settle any additional income taxes or the tax law does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purposes. When those circumstances exist, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The new financial statement presentation provisions relating to this update are prospective and effective for interim and annual periods beginning after December 15, 2013, with early adoption permitted. We adopted Accounting Standards Updated 2013-11 in the first quarter of 2014 which did not have a material impact on our financial condition, results of operations or cash flows.
	Financial Reporting of Discontinued Operations — In April 2014, the FASB issued Accounting Standards Update 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360)”. The update limits discontinued operations reporting to disposals that represent a strategic shift that has (or will have) a major effect on an entity's operations and financial results. The standard also requires new disclosures related to components reported as discontinued operations, as well as components of an entity that were sold and do not meet the criteria for discontinued operations reporting. The new financial statement presentation provisions relating to this update are prospective and effective for interim and annual periods beginning after December 15, 2014, with early adoption permitted. We are currently assessing the future impact of this update, but we do not anticipate a material impact on our financial condition, results of operations or cash flows.

Acquisition_Notes

Acquisition (Notes)	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	'
	2	Acquisition and Divestitures
	Acquisition of Guadalupe Energy Center
	On February 26, 2014, we, through our indirect, wholly-owned subsidiary Calpine Guadalupe GP, LLC, completed the purchase of a power plant owned by MinnTex Power Holdings, LLC with a nameplate capacity of 1,050 MW, for approximately $625 million, excluding working capital adjustments. The addition of this modern, natural gas-fired, combined-cycle power plant increased capacity in our Texas segment which is one of our core markets. The 110-acre site, located in Guadalupe County, Texas, which is northeast of San Antonio, Texas, includes two 525 MW generation blocks, each consisting of two GE 7FA combustion turbines, two heat recovery steam generators and one GE steam turbine. We also paid $15 million to acquire rights to an advanced development opportunity for an approximately 400 MW quick-start, natural gas-fired peaker. We funded the acquisition with $425 million in incremental CCFC Term Loans and cash on hand. See Note 4 for a further description of the incremental CCFC Term Loans. The purchase price was primarily allocated to property, plant and equipment. Although the purchase price allocation has not been finalized, we do not expect to record any material adjustments to the preliminary purchase price allocation nor do we expect to recognize any significant goodwill as a result of this acquisition. The pro forma incremental impact of Guadalupe Energy Center on our results of operations for the three months ended March 31, 2014 and 2013 is not material.
	Sale of Six Southeast Power Plants
	On April 17, 2014, we entered into a purchase and sale agreement, through our indirect wholly-owned subsidiaries, Calpine Project Holdings, Inc. and Calgen Expansion Company, LLC, to sell six of our power plants in the Southeast segment. The purchase and sale agreement allows for the sale of 100% of the limited liability company interests in (i) Mobile Energy LLC, (ii) Santa Rosa Energy Center, LLC, (iii) Carville Energy, LLC, (iv) Decatur Energy Center, LLC, (v) Columbia Energy LLC and (vi) Calpine Oneta Power, LLC and thereby sell assets comprising 3,498 MW of combined-cycle generation capacity in Oklahoma, Louisiana, Alabama, Florida and South Carolina for a purchase price of approximately $1.57 billion in cash, subject to working capital and other adjustments. The divestiture of these power plants will better align our asset base with our strategic focus on competitive wholesale markets. We expect to record a gain on sale of assets, net between approximately $725 million and $775 million depending upon the timing of closing which is targeted during the second quarter of 2014, subject to regulatory approvals. We expect to use existing federal and state NOLs to almost entirely offset the projected taxable gains from the sale.
	The six power plants included in the transaction are as follows:
	Plant Name		Plant Capacity		Location
	Oneta Energy Center		1,134	MW	Broken Arrow, OK
	Carville Energy Center(1)		501	MW	St. Gabriel, LA
	Decatur Energy Center		795	MW	Decatur, AL
	Hog Bayou Energy Center		237	MW	Mobile, AL
	Santa Rosa Energy Center		225	MW	Pace, FL
	Columbia Energy Center(1)		606	MW	Calhoun County, SC
	Total		3,498	MW
	___________
	-1	Indicates combined-cycle cogeneration power plant.

Variable_Interest_Entities_and

Variable Interest Entities and Unconsolidated Investments	3 Months Ended
	Mar. 31, 2014
Variable Interest Entities and Unconsolidated Investments [Abstract]	'
Variable Interest Entities and Unconsolidated Investments	'
	Variable Interest Entities and Unconsolidated Investments in Power Plants
	We consolidate all of our VIEs where we have determined that we are the primary beneficiary. There were no changes to our determination of whether we are the primary beneficiary of our VIEs for the three months ended March 31, 2014. See Note 5 in our 2013 Form 10-K for further information regarding our VIEs.
	VIE Disclosures
	Our consolidated VIEs include natural gas-fired power plants with an aggregate capacity of 9,849 MW and 9,427 MW at March 31, 2014 and December 31, 2013, respectively. For these VIEs, we may provide other operational and administrative support through various affiliate contractual arrangements among the VIEs, Calpine Corporation and its other wholly-owned subsidiaries whereby we support the VIE through the reimbursement of costs and/or the purchase and sale of energy. Other than amounts contractually required, we provided support to these VIEs in the form of cash and other contributions of approximately $40 million and nil during the three months ended March 31, 2014 and 2013, respectively.
	Unconsolidated VIEs and Investments in Power Plants
	We have a 50% partnership interest in Greenfield LP and in Whitby. Greenfield LP and Whitby are also VIEs; however, we do not have the power to direct the most significant activities of these entities and therefore do not consolidate them. Greenfield LP is a limited partnership between certain subsidiaries of ours and of Mitsui & Co., Ltd., which operates the Greenfield Energy Centre, a 1,038 MW natural gas-fired, combined-cycle power plant located in Ontario, Canada. We and Mitsui & Co., Ltd. each hold a 50% interest in Greenfield LP. Whitby is a limited partnership between certain of our subsidiaries and Atlantic Packaging Ltd., which operates the Whitby facility, a 50 MW natural gas-fired, simple-cycle cogeneration power plant located in Ontario, Canada. We and Atlantic Packaging Ltd. each hold a 50% partnership interest in Whitby.
	We account for these entities under the equity method of accounting and include our net equity interest in investments in power plants on our Consolidated Condensed Balance Sheets. At March 31, 2014 and December 31, 2013, our equity method investments included on our Consolidated Condensed Balance Sheets were comprised of the following (in millions):
		Ownership Interest as of		March 31, 2014				December 31, 2013
		31-Mar-14
	Greenfield LP	50%		$	77			$	76
	Whitby	50%		8				17
	Total investments in power plants			$	85			$	93
	Our risk of loss related to our unconsolidated VIEs is limited to our investment balance. Holders of the debt of our unconsolidated investments do not have recourse to Calpine Corporation and its other subsidiaries; therefore, the debt of our unconsolidated investments is not reflected on our Consolidated Condensed Balance Sheets. At March 31, 2014 and December 31, 2013, equity method investee debt was approximately $376 million and $395 million, respectively, and based on our pro rata share of each of the investments, our share of such debt would be approximately $188 million and $198 million at March 31, 2014 and December 31, 2013, respectively.
	Our equity interest in the net income from Greenfield LP and Whitby for the three months ended March 31, 2014 and 2013, is recorded in (income) from unconsolidated investments in power plants. The following table sets forth details of our (income) from unconsolidated investments in power plants for the periods indicated (in millions):
		Three Months Ended March 31,
		2014				2013
	Greenfield LP	$	(5	)		$	(4	)
	Whitby	(4		)		(4		)
	Total	$	(9	)		$	(8	)
	Distributions from Greenfield LP were nil during each of the three months ended March 31, 2014 and 2013. Distributions from Whitby were $13 million and nil during the three months ended March 31, 2014 and 2013, respectively.
	Inland Empire Energy Center Put and Call Options — We hold a call option to purchase the Inland Empire Energy Center (a 775 MW natural gas-fired power plant located in California) from GE that may be exercised between years 2017 and 2024. GE holds a put option whereby they can require us to purchase the power plant, if certain plant performance criteria are met by 2025. We determined that we are not the primary beneficiary of the Inland Empire power plant, and we do not consolidate it due to the fact that GE directs the most significant activities of the power plant including operations and maintenance.

Debt

Debt	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt	'
	Debt
	At March 31, 2014 and December 31, 2013, our debt was as follows (in millions):
		March 31, 2014		December 31, 2013
	First Lien Notes	$	4,989	$	4,989
	First Lien Term Loans	2,821		2,828
	Project financing, notes payable and other	1,865		1,901
	CCFC Term Loans	1,607		1,191
	Capital lease obligations	193		203
	Subtotal	11,475		11,112
	Less: Current maturities	189		204
	Total long-term debt	$	11,286	$	10,908
	Our effective interest rate on our consolidated debt, excluding the impacts of capitalized interest and unrealized gains (losses) on interest rate swaps, decreased to 6.2% for the three months ended March 31, 2014, from 7.0% for the three months ended March 31, 2013. The issuance of our CCFC Term Loans, 2022 First Lien Notes, 2024 First Lien Notes and 2020 First Lien Term Loan in 2013 allowed us to reduce our overall cost of debt by replacing our CCFC Notes and a portion of our First Lien Notes with debt carrying lower interest rates.
	First Lien Notes
	Our First Lien Notes are summarized in the table below (in millions):
		March 31, 2014		December 31, 2013
	2019 First Lien Notes	$	320	$	320
	2020 First Lien Notes	875		875
	2021 First Lien Notes	1,600		1,600
	2022 First Lien Notes	744		744
	2023 First Lien Notes	960		960
	2024 First Lien Notes	490		490
	Total First Lien Notes	$	4,989	$	4,989
	First Lien Term Loans
	Our First Lien Term Loans are summarized in the table below (in millions):
		March 31, 2014		December 31, 2013
	2018 First Lien Term Loans	$	1,610	$	1,614
	2019 First Lien Term Loan	822		824
	2020 First Lien Term Loan	389		390
	Total First Lien Term Loans	$	2,821	$	2,828
	CCFC Term Loans
	In February 2014, we executed an amendment to the credit agreement associated with the CCFC Term Loans, which allowed us to issue $425 million in incremental CCFC Term Loans to fund a portion of the purchase price paid in connection with the closing of our acquisition of Guadalupe Energy Center on February 26, 2014. Guadalupe Energy Center was purchased by Calpine Guadalupe GP, LLC, a wholly-owned subsidiary of CCFC. The incremental term loans carry substantially the same terms and conditions as the $300 million in aggregate principal amount of CCFC Term Loans issued in June 2013. The incremental term loans were offered to investors at an issue price equal to 98.75% of face value.
	Corporate Revolving Facility and Other Letters of Credit Facilities
	The table below represents amounts issued under our letter of credit facilities at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Corporate Revolving Facility(1)	$	239	$	242
	CDHI	240		218
	Various project financing facilities	170		170
	Total	$	649	$	630
	____________
	-1	The Corporate Revolving Facility represents our primary revolving facility.
	CDHI
	During the first quarter of 2014, we amended our CDHI letter of credit facility to lower our fees and extend the maturity to January 2, 2018.
	Fair Value of Debt
	We record our debt instruments based on contractual terms, net of any applicable premium or discount. We did not elect to apply the alternative U.S. GAAP provisions of the fair value option for recording financial assets and financial liabilities. The following table details the fair values and carrying values of our debt instruments at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014				December 31, 2013
		Fair Value		Carrying		Fair Value		Carrying
				Value				Value
	First Lien Notes	$	5,418	$	4,989	$	5,317	$	4,989
	First Lien Term Loans	2,826		2,821		2,845		2,828
	Project financing, notes payable and other(1)	1,751		1,743		1,772		1,766
	CCFC Term Loans	1,590		1,607		1,179		1,191
	Total	$	11,585	$	11,160	$	11,113	$	10,774
	____________
	-1	Excludes a lease that is accounted for as a failed sale-leaseback transaction under U.S. GAAP.
	We measure the fair value of our First Lien Notes, First Lien Term Loans and CCFC Term Loans using market information, including quoted market prices or dealer quotes for the identical liability when traded as an asset (categorized as level 2). We measure the fair value of our project financing, notes payable and other debt instruments using discounted cash flow analyses based on our current borrowing rates for similar types of borrowing arrangements (categorized as level 3). We do not have any debt instruments with fair value measurements categorized as level 1 within the fair value hierarchy.

Assets_and_Liabilities_with_Re

Assets and Liabilities with Recurring Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Measurements [Abstract]	'
Assets and Liabilities with Recurring Fair Value Measurements	'
	Assets and Liabilities with Recurring Fair Value Measurements
	Cash Equivalents — Highly liquid investments which meet the definition of cash equivalents, primarily investments in money market accounts, are included in both our cash and cash equivalents and our restricted cash on our Consolidated Condensed Balance Sheets. Certain of our money market accounts invest in U.S. Treasury securities or other obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities. Our cash equivalents are classified within level 1 of the fair value hierarchy.
	Margin Deposits and Margin Deposits Posted with Us by Our Counterparties — Margin deposits and margin deposits posted with us by our counterparties represent cash collateral paid between our counterparties and us to support our commodity contracts. Our margin deposits and margin deposits posted with us by our counterparties are generally cash and cash equivalents and are classified within level 1 of the fair value hierarchy.
	Derivatives — The primary factors affecting the fair value of our derivative instruments at any point in time are the volume of open derivative positions (MMBtu, MWh and $ notional amounts); changing commodity market prices, primarily for power and natural gas; our credit standing and that of our counterparties for energy commodity derivatives; and prevailing interest rates for our interest rate swaps. Prices for power and natural gas and interest rates are volatile, which can result in material changes in the fair value measurements reported in our financial statements in the future.
	We utilize market data, such as pricing services and broker quotes, and assumptions that we believe market participants would use in pricing our assets or liabilities including assumptions about the risks inherent to the inputs in the valuation technique. These inputs can be either readily observable, market corroborated or generally unobservable. The market data obtained from broker pricing services is evaluated to determine the nature of the quotes obtained and, where accepted as a reliable quote, used to validate our assessment of fair value. We use other qualitative assessments to determine the level of activity in any given market. We primarily apply the market approach and income approach for recurring fair value measurements and utilize what we believe to be the best available information. We utilize valuation techniques that seek to maximize the use of observable inputs and minimize the use of unobservable inputs. We classify fair value balances based on the observability of those inputs.
	The fair value of our derivatives includes consideration of our credit standing, the credit standing of our counterparties and the impact of credit enhancements, if any. We have also recorded credit reserves in the determination of fair value based on our expectation of how market participants would determine fair value. Such valuation adjustments are generally based on market evidence, if available, or our best estimate.
	Our level 1 fair value derivative instruments primarily consist of power and natural gas swaps, futures and options traded on the NYMEX or Intercontinental Exchange.
	Our level 2 fair value derivative instruments primarily consist of interest rate swaps and OTC power and natural gas forwards for which market-based pricing inputs are observable. Generally, we obtain our level 2 pricing inputs from market sources such as the Intercontinental Exchange and Bloomberg. To the extent we obtain prices from brokers in the marketplace, we have procedures in place to ensure that prices represent executable prices for market participants. In certain instances, our level 2 derivative instruments may utilize models to measure fair value. These models are industry-standard models that incorporate various assumptions, including quoted interest rates, correlation, volatility, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace.
	Our level 3 fair value derivative instruments may consist of OTC power and natural gas forwards and options where pricing inputs are unobservable, as well as other complex and structured transactions. Complex or structured transactions are tailored to our or our customers’ needs and can introduce the need for internally-developed model inputs which might not be observable in or corroborated by the market. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized in level 3. Our valuation models may incorporate historical correlation information and extrapolate available broker and other information to future periods. OTC options are valued using industry-standard models, including the Black-Scholes option-pricing model. At each balance sheet date, we perform an analysis of all instruments subject to fair value measurement and include in level 3 all of those whose fair value is based on significant unobservable inputs.
	Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect our estimate of the fair value of our assets and liabilities and their placement within the fair value hierarchy levels. The following tables present our financial assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2014 and December 31, 2013, by level within the fair value hierarchy:
		Assets and Liabilities with Recurring Fair Value Measures as of March 31, 2014
		Level 1			Level 2				Level 3		Total
		(in millions)
	Assets:
	Cash equivalents(1)	$	717		$	—			$	—	$	717
	Margin deposits	235			—				—		235
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	717			—				—		717
	Commodity forward contracts(2)	—			69				36		105
	Interest rate swaps	—			7				—		7
	Total assets	$	1,669		$	76			$	36	$	1,781
	Liabilities:
	Margin deposits posted with us by our counterparties	$	18		$	—			$	—	$	18
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	684			—				—		684
	Commodity forward contracts(2)	—			120				28		148
	Interest rate swaps	—			126				—		126
	Total liabilities	$	702		$	246			$	28	$	976
		Assets and Liabilities with Recurring Fair Value Measures as of December 31, 2013
		Level 1			Level 2				Level 3		Total
		(in millions)
	Assets:
	Cash equivalents(1)	$	1,134		$	—			$	—	$	1,134
	Margin deposits	261			—				—		261
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	434			—				—		434
	Commodity forward contracts(2)	—			75				32		107
	Interest rate swaps	—			9				—		9
	Total assets	$	1,829		$	84			$	32	$	1,945
	Liabilities:
	Margin deposits posted with us by our counterparties	$	5		$	—			$	—	$	5
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	495			—				—		495
	Commodity forward contracts(2)	—			52				18		70
	Interest rate swaps	—			129				—		129
	Total liabilities	$	500		$	181			$	18	$	699
	___________
	-1	As of March 31, 2014 and December 31, 2013, we had cash equivalents of $478 million and $889 million included in cash and cash equivalents and $239 million and $245 million included in restricted cash, respectively.
	-2	Includes OTC swaps and options.
	At March 31, 2014, the derivative instruments classified as level 3 primarily included financial power congestion products which settle on the price differential between two power delivery locations, at least one of which is deemed unobservable. The fair value of the net derivative position classified as level 3 is predominantly driven by market commodity prices; however, given the nature of our net derivative position, we do not believe that a significant change in market commodity prices would have a material impact on our level 3 net fair value. The following table presents quantitative information for the unobservable inputs used in our most significant level 3 fair value measurements at March 31, 2014 and December 31, 2013:
			Quantitative Information about Level 3 Fair Value Measurements
			31-Mar-14
			Fair Value, Net Asset					Significant Unobservable
			(Liability)			Valuation Technique		Input		Range
			(in millions)
	Power Congestion Products		$	7		Discounted cash flow		Market price (per MWh)		$(8.79) — $11.53/MWh
			31-Dec-13
			Fair Value, Net Asset					Significant Unobservable
			(Liability)			Valuation Technique		Input		Range
			(in millions)
	Physical Power		$	7		Discounted cash flow		Market price (per MWh)		$28.92 — $53.15/MWh
	Power Congestion Products		$	7		Discounted cash flow		Market price (per MWh)		$(8.79) — $11.53/MWh
	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 March 31,
	2014			2013
Balance, beginning of period	$	14		$	16
Realized and unrealized gains (losses):
Included in net loss:
Included in operating revenues(1)	(10		)	1
Included in fuel and purchased energy expense(2)	5			—
Purchases and settlements:
Purchases	1			—
Settlements	(3		)	(3		)
Transfers in and/or out of level 3(3):
Transfers into level 3(4)	—			—
Transfers out of level 3(5)	1			(1		)
Balance, end of period	$	8		$	13
Change in unrealized gains (losses) relating to instruments still held at end of period	$	(5	)	$	1
___________
-1	For power contracts and other power-related products, included on our Consolidated Condensed Statements of Operations.
-2	For natural gas 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 months ended March 31, 2014 and 2013.
-4	There were no transfers out of level 2 into level 3 for each of the three months ended March 31, 2014 and 2013.
-5	We had $1 million in losses and $1 million in gains transferred out of level 3 into level 2 for the three months ended March 31, 2014 and 2013, respectively, due to changes in market liquidity in various power markets.

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments [Abstract]	'
Derivative Instruments	'
	Derivative Instruments
	Types of Derivative Instruments and Volumetric Information
	Commodity Instruments — We are exposed to changes in prices for the purchase and sale of power, natural gas, environmental products and other energy commodities. We use derivatives, which include physical commodity contracts and financial commodity instruments such as OTC and exchange traded swaps, futures, options, forward agreements and instruments that settle on the power price to natural gas price relationships (Heat Rate swaps and options) or instruments that settle on power price relationships between delivery points for the purchase and sale of power and natural gas to attempt to maximize the risk-adjusted returns by economically hedging a portion of the commodity price risk associated with our assets. By entering into these transactions, we are able to economically hedge a portion of our Spark Spread at estimated generation and prevailing price levels.
	We also engage in limited trading activities, as authorized by our Board of Directors and monitored by our Chief Risk Officer and Risk Management Committee of senior management, related to our commodity derivative portfolio which exposes us to certain market risks that are segregated from the market risks of our underlying asset portfolio. These transactions are executed primarily for the purpose of providing improved price and price volatility discovery, greater market access, and profiting from our market knowledge, all of which benefit our asset hedging activities. Our realized and unrealized trading gains and losses were not material for the three months ended March 31, 2014 and 2013.
	Interest Rate Swaps — A portion of our debt is indexed to base rates, primarily LIBOR. We have historically used interest rate swaps to adjust the mix between fixed and floating rate debt to hedge our interest rate risk for potential adverse changes in interest rates. As of March 31, 2014, the maximum length of time over which we were hedging using interest rate derivative instruments designated as cash flow hedges was 10 years.
	As of March 31, 2014 and December 31, 2013, the net forward notional buy (sell) position of our outstanding commodity and interest rate swap contracts that did not qualify or were not designated under the normal purchase normal sale exemption were as follows (in millions):
	Derivative Instruments		Notional Amounts
			March 31, 2014				December 31, 2013
	Power (MWh)		(29		)		(29		)
	Natural gas (MMBtu)		541				448
	Environmental credits (Tonnes)		2				—
	Interest rate swaps		$	1,517			$	1,527
	Certain of our derivative instruments contain credit risk-related contingent provisions that require us to maintain collateral balances consistent with our credit ratings. If our credit rating were to be downgraded, it could require us to post additional collateral or could potentially allow our counterparty to request immediate, full settlement on certain derivative instruments in liability positions. Currently, we do not believe that it is probable that any additional collateral posted as a result of a one credit notch downgrade from its current level would be material. The aggregate fair value of our derivative liabilities with credit risk-related contingent provisions as of March 31, 2014, was $58 million for which we have posted collateral of $7 million by posting margin deposits or granting additional first priority liens on the assets currently subject to first priority liens under our First Lien Notes, First Lien Term Loans and Corporate Revolving Facility. However, if our credit rating were downgraded by one notch from its current level, we estimate that $1 million additional collateral would be required and that no counterparty could request immediate, full settlement.
	Accounting for Derivative Instruments
	We recognize all derivative instruments that qualify for derivative accounting treatment as either assets or liabilities and measure those instruments at fair value unless they qualify for, and we elect, the normal purchase normal sale exemption. For transactions in which we elect the normal purchase normal sale exemption, gains and losses are not reflected on our Consolidated Condensed Statements of Operations until the period of delivery. Revenues and fuel costs derived from instruments that qualified for hedge accounting or represent an economic hedge are recorded in the same financial statement line item as the item being hedged. Hedge accounting requires us to formally document, designate and assess the effectiveness of transactions that receive hedge accounting. We present the cash flows from our derivatives in the same category as the item being hedged (or economically hedged) within operating activities or investing activities on our Consolidated Condensed Statements of Cash Flows unless they contain an other-than-insignificant financing element in which case their cash flows are classified within financing activities.
	Cash Flow Hedges — We report the effective portion of the unrealized gain or loss on a derivative instrument designated and qualifying as a cash flow hedging instrument as a component of OCI and reclassify such gains and losses into earnings in the same period during which the hedged forecasted transaction affects earnings. During the three months ended March 31, 2014 and 2013, we did not have any commodity derivative instruments designated as cash flow hedges. Gains and losses due to ineffectiveness on interest rate hedging instruments are recognized currently in earnings as a component of interest expense. If it is determined that the forecasted transaction is no longer probable of occurring, then hedge accounting will be discontinued prospectively and future changes in fair value are recorded in earnings. If the hedging instrument is terminated or de-designated prior to the occurrence of the hedged forecasted transaction, the net accumulated gain or loss associated with the changes in fair value of the hedge instrument remains deferred in AOCI until such time as the forecasted transaction impacts earnings or until it is determined that the forecasted transaction is probable of not occurring.
	Derivatives Not Designated as Hedging Instruments — We enter into power, natural gas, interest rate and environmental product transactions that primarily act as economic hedges to our asset and interest rate portfolio, but either do not qualify as hedges under the hedge accounting guidelines or qualify under the hedge accounting guidelines and the hedge accounting designation has not been elected. Changes in fair value of commodity derivatives not designated as hedging instruments are recognized currently in earnings and are separately stated on our Consolidated Condensed Statements of Operations in unrealized mark-to-market gain/loss as a component of operating revenues (for power and environmental product contracts and Heat Rate swaps and options) and fuel and purchased energy expense (for natural gas contracts, swaps and options). Changes in fair value of interest rate derivatives not designated as hedging instruments are recognized currently in earnings as interest expense.
	Derivatives Included on Our Consolidated Condensed Balance Sheets
	The following tables present the fair values of our derivative instruments recorded on our Consolidated Condensed Balance Sheets by location and hedge type at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014
		Commodity				Interest Rate				Total
		Instruments				Swaps				Derivative
										Instruments
	Balance Sheet Presentation
	Current derivative assets	$	655			$	—			$	655
	Long-term derivative assets	167				7				174
	Total derivative assets	$	822			$	7			$	829
	Current derivative liabilities	$	681			$	47			$	728
	Long-term derivative liabilities	151				79				230
	Total derivative liabilities	$	832			$	126			$	958
	Net derivative liabilities	$	(10	)		$	(119	)		$	(129	)
		December 31, 2013
		Commodity				Interest Rate				Total
		Instruments				Swaps				Derivative
										Instruments
	Balance Sheet Presentation
	Current derivative assets	$	445			$	—			$	445
	Long-term derivative assets	96				9				105
	Total derivative assets	$	541			$	9			$	550
	Current derivative liabilities	$	404			$	47			$	451
	Long-term derivative liabilities	161				82				243
	Total derivative liabilities	$	565			$	129			$	694
	Net derivative liabilities	$	(24	)		$	(120	)		$	(144	)
		March 31, 2014								December 31, 2013
		Fair Value				Fair Value				Fair Value				Fair Value
		of Derivative				of Derivative				of Derivative				of Derivative
		Assets				Liabilities				Assets				Liabilities
	Derivatives designated as cash flow hedging instruments:
	Interest rate swaps	$	7			$	113			$	9			$	115
	Total derivatives designated as cash flow hedging instruments	$	7			$	113			$	9			$	115
	Derivatives not designated as hedging instruments:
	Commodity instruments	$	822			$	832			$	541			$	565
	Interest rate swaps	—				13				—				14
	Total derivatives not designated as hedging instruments	$	822			$	845			$	541			$	579
	Total derivatives	$	829			$	958			$	550			$	694
	We elected not to offset fair value amounts recognized as derivative instruments on our Consolidated Condensed Balance Sheets that are executed with the same counterparty under master netting arrangements or other contractual netting provisions negotiated with the counterparty. Our netting arrangements include a right to set off or net together purchases and sales of similar products in the margining or settlement process. In some instances, we have also negotiated cross commodity netting rights which allow for the net presentation of activity with a given counterparty regardless of product purchased or sold. We also post cash collateral in support of our derivative instruments which may also be subject to a master netting arrangement with the same counterparty. The tables below set forth our net exposure to derivative instruments after offsetting amounts subject to a master netting arrangement with the same counterparty at March 31, 2014 and December 31, 2013 (in millions):
			March 31, 2014
			Gross Amounts Not Offset on the Consolidated Condensed Balance Sheets
			Gross Amounts Presented on our Consolidated Condensed Balance Sheets				Derivative Asset (Liability) not Offset on the Consolidated Condensed Balance Sheets				Margin/Cash (Received) Posted (1)				Net Amount
	Derivative assets:
	Commodity exchange traded futures and swaps contracts		$	717			$	(669	)		$	(48	)		$	—
	Commodity forward contracts		105				(78		)		—				27
	Interest rate swaps		7				—				—				7
Total derivative assets		$	829			$	(747	)		$	(48	)		$	34
Derivative (liabilities):
Commodity exchange traded futures and swaps contracts		$	(684	)		$	669			$	15			$	—
Commodity forward contracts		(148		)		78				7				(63		)
Interest rate swaps		(126		)		—				—				(126		)
Total derivative (liabilities)		$	(958	)		$	747			$	22			$	(189	)
Net derivative assets (liabilities)		$	(129	)		$	—			$	(26	)		$	(155	)
		31-Dec-13
		Gross Amounts Not Offset on the Consolidated Condensed Balance Sheets
		Gross Amounts Presented on our Consolidated Condensed Balance Sheets				Derivative Asset (Liability) not Offset on the Consolidated Condensed Balance Sheets				Margin/Cash (Received) Posted (1)				Net Amount
Derivative assets:
Commodity exchange traded futures and swaps contracts		$	434			$	(420	)		$	(14	)		$	—
Commodity forward contracts		107				(60		)		—				47
Interest rate swaps		9				—				—				9
Total derivative assets		$	550			$	(480	)		$	(14	)		$	56
Derivative (liabilities):
Commodity exchange traded futures and swaps contracts		$	(495	)		$	420			$	75			$	—
Commodity forward contracts		(70		)		60				1				(9		)
Interest rate swaps		(129		)		—				—				(129		)
Total derivative (liabilities)		$	(694	)		$	480			$	76			$	(138	)
Net derivative assets (liabilities)		$	(144	)		$	—			$	62			$	(82	)
____________
-1	Negative balances represent margin deposits posted with us by our counterparties related to our derivative activities that are subject to a master netting arrangement. Positive balances reflect margin deposits posted by us with our counterparties related to our derivative activities that are subject to a master netting arrangement. See Note 7 for a further discussion of our collateral.
Derivatives Included on Our Consolidated Condensed Statements of Operations
Changes in the fair values of our derivative instruments (both assets and liabilities) are reflected either in cash for option premiums paid or collected, in OCI, net of tax, for the effective portion of derivative instruments which qualify for and we have elected cash flow hedge accounting treatment, or on our Consolidated Condensed Statements of Operations as a component of unrealized mark-to-market activity within our earnings.
The following tables detail the components of our total mark-to-market activity for both the net realized gain (loss) and the net unrealized gain (loss) recognized from our derivative instruments in earnings and where these components were recorded on our Consolidated Condensed Statements of Operations for the periods indicated (in millions):
	Three Months Ended March 31,
	2014				2013
Realized gain (loss)(1)
Commodity derivative instruments	$	(39	)		$	28
Total realized gain (loss)	$	(39	)		$	28
Unrealized gain (loss)(2)
Commodity derivative instruments	$	(73	)		$	(57	)
Interest rate swaps	1				2
Total unrealized gain (loss)	$	(72	)		$	(55	)
Total mark-to-market activity, net	$	(111	)		$	(27	)
___________
-1	Does not include the realized value associated with derivative instruments that settle through physical delivery.
-2	In addition to changes in market value on derivatives not designated as hedges, changes in unrealized gain (loss) also includes de-designation of interest rate swap cash flow hedges and related reclassification from AOCI into earnings, hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.
	Three Months Ended March 31,
	2014				2013
Realized and unrealized gain (loss)
Derivatives contracts included in operating revenues	$	(237	)		$	(74	)
Derivatives contracts included in fuel and purchased energy expense	125				45
Interest rate swaps included in interest expense	1				2
Total mark-to-market activity, net	$	(111	)		$	(27	)
Derivatives Included in OCI and AOCI
We do not have any commodity derivative instruments that were designated as cash flow hedges during the three months ended March 31, 2014 and 2013. The following table details the effect of our net derivative instruments that qualified for hedge accounting treatment and are included in OCI and AOCI for the periods indicated (in millions):
	Three Months Ended March 31,								Three Months Ended March 31,
	Gain (Loss) Recognized  in								Gain (Loss) Reclassified from
	OCI (Effective Portion)								AOCI into Income (Effective Portion)(3)
	2014				2013				2014				2013				Affected Line Item on the Consolidated Condensed Statements of Operations
Interest rate swaps(1)	$	—			$	13			$	(13	)	(4)	$	(9	)		Interest expense
Total(2)	$	—			$	13			$	(13	)		$	(9	)
____________
-1	We did not record any gain (loss) on hedge ineffectiveness related to our interest rate swaps designated as cash flow hedges during the three months ended March 31, 2014 and 2013.
-2	We recorded an income tax benefit of nil and $1 million for the three months ended March 31, 2014 and 2013, respectively, in AOCI related to our cash flow hedging activities.
-3	Cumulative cash flow hedge losses attributable to Calpine, net of tax, remaining in AOCI were $148 million at each of March 31, 2014 and December 31, 2013. Cumulative cash flow hedge losses attributable to the noncontrolling interest, net of tax, remaining in AOCI were $11 million at each of March 31, 2014 and December 31, 2013.
-4	Includes a loss of $5 million that was reclassified from AOCI to interest expense for the three months ended March 31, 2014 where the hedged transactions are no longer expected to occur.
We estimate that pre-tax net losses of $43 million would be reclassified from AOCI into interest expense during the next 12 months as the hedged transactions settle; however, the actual amounts that will be reclassified will likely vary based on changes in interest rates. Therefore, we are unable to predict what the actual reclassification from AOCI into earnings (positive or negative) will be for the next 12 months.

Use_of_Collateral

Use of Collateral	3 Months Ended
	Mar. 31, 2014
Use of Collateral [Abstract]	'
Use of Collateral [Text Block]	'
	Use of Collateral
	We use margin deposits, prepayments and letters of credit as credit support with and from our counterparties for commodity procurement and risk management activities. In addition, we have granted additional first priority liens on the assets currently subject to first priority liens under various debt agreements as collateral under certain of our power and natural gas agreements and certain of our interest rate swap agreements in order to reduce the cash collateral and letters of credit that we would otherwise be required to provide to the counterparties under such agreements. The counterparties under such agreements share the benefits of the collateral subject to such first priority liens pro rata with the lenders under our various debt agreements.
	The table below summarizes the balances outstanding under margin deposits, natural gas and power prepayments, and exposure under letters of credit and first priority liens for commodity procurement and risk management activities as of March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Margin deposits(1)	$	235	$	261
	Natural gas and power prepayments	29		28
	Total margin deposits and natural gas and power prepayments with our counterparties(2)	$	264	$	289
	Letters of credit issued	$	536	$	488
	First priority liens under power and natural gas agreements	24		31
	First priority liens under interest rate swap agreements	128		132
	Total letters of credit and first priority liens with our counterparties	$	688	$	651
	Margin deposits posted with us by our counterparties(1)(3)	$	18	$	5
	Letters of credit posted with us by our counterparties	2		2
	Total margin deposits and letters of credit posted with us by our counterparties	$	20	$	7
	___________
	-1	Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.
	-2	At March 31, 2014 and December 31, 2013, $249 million and $272 million, respectively, were included in margin deposits and other prepaid expense and $15 million and $17 million, respectively, were included in other assets on our Consolidated Condensed Balance Sheets.
	-3	Included in other current liabilities on our Consolidated Condensed Balance Sheets.
	Future collateral requirements for cash, first priority liens and letters of credit may increase or decrease based on the extent of our involvement in hedging and optimization contracts, movements in commodity prices, and also based on our credit ratings and general perception of creditworthiness in our market.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Income Tax Benefit
	The table below shows our consolidated income tax benefit from continuing operations (excluding noncontrolling interest) and our effective tax rates for the periods indicated (in millions):
		Three Months Ended March 31,
		2014			2013
	Income tax benefit	$	(19	)	$	(50	)
	Effective tax rate	53		%	29		%
	Income Tax Audits — We remain subject to periodic audits and reviews by taxing authorities; however, we do not expect these audits will have a material effect on our tax provision. Any NOLs we claim in future years to reduce taxable income could be subject to IRS examination regardless of when the NOLs occurred. Due to significant NOLs, any adjustment of state returns or federal returns would likely result in a reduction of deferred tax assets rather than a cash payment of income taxes.
	Canadian Tax Audits — In January 2013, we received an adjusted reassessment on one of two transfer pricing issues that we are disputing with the Canadian Revenue Authority (“CRA”). We proposed a settlement of the adjusted reassessment with the CRA and it has accepted our proposal. The adjustment to our transfer pricing increased taxable income and was offset by existing NOLs to which a valuation allowance had been applied and did not have a material impact on the financial statements.
	On January 28, 2014, we received a letter from the CRA which informed us that they do not agree with our transfer price on the second issue and will be proposing an increase to taxable income for tax years 2006 and 2007. We continue to believe that our transfer pricing positions and policies are appropriate, and we intend to vigorously defend our position and challenge the CRA’s adjustments, including but not limited to appeal and litigation. If we are unsuccessful in our challenge, any adjustment to Canadian taxable income would first be offset against the existing NOLs that are available. If our existing Canadian NOL’s are not sufficient to offset the resulting adjustment to taxable income, additional assessments, including penalties and interest, if any, would not have a material adverse effect on our financial condition, results of operations or cash flows.
	Valuation Allowance — U.S. GAAP requires that we consider all available evidence, both positive and negative, and tax planning strategies to determine whether, based on the weight of that evidence, a valuation allowance is needed to reduce the value of deferred tax assets. Future realization of the tax benefit of an existing deductible temporary difference or carryforward ultimately depends on the existence of sufficient taxable income of the appropriate character within the carryback or carryforward periods available under the tax law. Due to our history of losses, we are unable to assume future profits; however, we are able to consider available tax planning strategies.
	Unrecognized Tax Benefits — At March 31, 2014, we had unrecognized tax benefits of $66 million. If recognized, $16 million of our unrecognized tax benefits could impact the annual effective tax rate and $50 million, related to deferred tax assets, could be offset against the recorded valuation allowance resulting in no impact on our effective tax rate. We also had accrued interest and penalties of $13 million for income tax matters at March 31, 2014. We recognize interest and penalties related to unrecognized tax benefits in income tax expense (benefit) on our Consolidated Condensed Statements of Operations. We believe it is reasonably possible that a decrease within the range of nil and $9 million in unrecognized tax benefits could occur within the next 12 months primarily related to foreign tax issues.

Earnings_Loss_per_Share

Earnings (Loss) per Share	3 Months Ended
	Mar. 31, 2014
Earnings (Loss) per Share [Abstract]	'
Earnings (Loss) per Share	'
	Loss per Share
	We include restricted stock units for which no future service is required as a condition to the delivery of the underlying common stock in our calculation of weighted average shares outstanding. As we incurred a net loss for each of the three months ended March 31, 2014 and 2013, diluted loss per share for both periods are computed on the same basis as basic loss per share, as the inclusion of any other potential shares outstanding would be anti-dilutive. We excluded the following items from diluted loss per common share for the three months ended March 31, 2014 and 2013, because they were anti-dilutive (shares in thousands):
		Three Months Ended March 31,
		2014	2013
	Share-based awards	8,995	10,963

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	Stock-Based Compensation
	Calpine Equity Incentive Plans
	The Calpine Equity Incentive Plans provide for the issuance of equity awards to all non-union employees as well as the non-employee members of our Board of Directors. The equity awards may include incentive or non-qualified stock options, restricted stock, restricted stock units, stock appreciation rights, performance compensation awards and other share-based awards. The equity awards granted under the Calpine Equity Incentive Plans include both graded and cliff vesting awards which vest over periods between one and five years, contain contractual terms between approximately five and ten years and are subject to forfeiture provisions under certain circumstances, including termination of employment prior to vesting. At March 31, 2014, there were 567,000 and 40,533,000 shares of our common stock authorized for issuance to participants under the Director Plan and the Equity Plan, respectively.
	Equity Classified Share-Based Awards
	We use the Black-Scholes option-pricing model or the Monte Carlo simulation model, as appropriate, to estimate the fair value of our employee stock options on the grant date, which takes into account the exercise price and expected term of the stock option, the current price of the underlying stock and its expected volatility, expected dividends on the stock and the risk-free interest rate for the expected term of the stock option as of the grant date. For our restricted stock and restricted stock units, we use our closing stock price on the date of grant, or the last trading day preceding the grant date for restricted stock granted on non-trading days, as the fair value for measuring compensation expense. Stock-based compensation expense is recognized over the period in which the related employee services are rendered. The service period is generally presumed to begin on the grant date and end when the equity award is fully vested. We use the graded vesting attribution method to recognize fair value of the equity award over the service period. For example, the graded vesting attribution method views one three-year restricted stock grant with annual graded vesting as three separate sub-grants, each representing 33 1/3% of the total number of shares of restricted stock granted. The first sub-grant vests over one year, the second sub-grant vests over two years and the third sub-grant vests over three years. A three-year restricted stock grant with cliff vesting is viewed as one grant vesting over three years.
	Stock-based compensation expense recognized for our equity classified share-based awards was $9 million and $8 million for the three months ended March 31, 2014 and 2013, respectively. We did not record any significant tax benefits related to stock-based compensation expense in any period as we are not benefiting from a significant portion of our deferred tax assets, including deductions related to stock-based compensation expense. In addition, we did not capitalize any stock-based compensation expense as part of the cost of an asset for the three months ended March 31, 2014 and 2013. At March 31, 2014, there was unrecognized compensation cost of $1 million related to options, $47 million related to restricted stock and nil related to restricted stock units, which is expected to be recognized over a weighted average period of 0.9 years for options, 1.7 years for restricted stock and 0.1 years for restricted stock units. We issue new shares from our share reserves set aside for the Calpine Equity Incentive Plans and employment inducement options when stock options are exercised and for other share-based awards.
	A summary of all of our non-qualified stock option activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted Average		Weighted	Aggregate
		Shares			Exercise Price		Average	Intrinsic Value
							Remaining	(in millions)
							Term
							(in years)
	Outstanding — December 31, 2013	14,114,289			$	18.25	3.1	$	36
	Granted	—			$	—
	Exercised	184,931			$	15.56
	Forfeited	—			$	—
	Expired	1,500			$	17.39
	Outstanding — March 31, 2014	13,927,858			$	18.29	2.8	$	48
	Exercisable — March 31, 2014	13,012,308			$	18.5	2.5	$	43
	Vested and expected to vest – March 31, 2014	13,871,693			$	18.3	2.8	$	48
	The total intrinsic value of our employee stock options exercised was $1 million and $2 million for the three months ended March 31, 2014 and 2013, respectively. The total cash proceeds received from our employee stock options exercised was $3 million and $9 million for the three months ended March 31, 2014 and 2013, respectively.
	There were no stock options granted during the three months ended March 31, 2014. The fair value of options granted during the three months ended March 31, 2013 was determined on the grant date using the Black-Scholes option-pricing model. Certain assumptions were used in order to estimate fair value for options as noted in the following table:
		2013
	Expected term (in years)(1)	6.5
	Risk-free interest rate(2)	1.4			%
	Expected volatility(3)	25.6			%
	Dividend yield(4)	—
	Weighted average grant-date fair value (per option)	$	5.31
	___________
	-1	Expected term calculated using the simplified method prescribed by the SEC due to the lack of sufficient historical exercise data on the grant date to provide a reasonable basis to estimate the expected term.
	-2	Zero Coupon U.S. Treasury rate or equivalent based on expected term.
	-3	Volatility calculated using the implied volatility of our exchange traded stock options.
	-4	We have never paid cash dividends on our common stock, and we do not anticipate any cash dividend payments on our common stock in the near future.
	A summary of our restricted stock and restricted stock unit activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted
		Restricted			Average
		Stock Awards			Grant-Date
					Fair Value
	Nonvested — December 31, 2013	4,431,841			$	16.45
	Granted	1,764,446			$	19.11
	Forfeited	25,977			$	17.03
	Vested	1,434,614			$	15.07
	Nonvested — March 31, 2014	4,735,696			$	17.86
	The total fair value of our restricted stock and restricted stock units that vested during the three months ended March 31, 2014 and 2013, was approximately $29 million and $20 million, respectively.
	Liability Classified Share-Based Awards
	During the first quarter of 2014 our Board of Directors approved the award of performance share units to certain senior management employees. These performance share units will be settled in cash with payouts based on the relative performance of Calpine’s TSR over the three-year performance period of January 1, 2014 through December 31, 2016 compared with the TSR performance of the S&P 500 companies over the same period. The performance share units vest on the last day of the performance period and will be settled in cash; thus, these awards are liability classified and are measured at fair value using a Monte Carlo simulation model at each reporting date until settlement. Stock-based compensation expense recognized related to our liability classified share-based awards was $1 million and nil for the three months ended March 31, 2014 and 2013, respectively.
	A summary of our performance share unit activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted
		Performance Share Units			Average
					Grant-Date
					Fair Value
	Nonvested — December 31, 2013	449,798			$	21.25
	Granted	461,393			$	22.56
	Forfeited	—			$	—
	Vested	15,312		(1)	$	21.25
	Nonvested — March 31, 2014	895,879			$	21.92
	___________
	-1	In accordance with the applicable performance share unit agreements, performance share units granted to employees who meet the retirement eligibility requirements stipulated in the Equity Plan are fully vested upon the later of the date on which the employee becomes eligible to retire or one-year anniversary of the grant date.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Litigation
	We are party to various litigation matters, including regulatory and administrative proceedings arising out of the normal course of business. At the present time, we do not expect that the outcome of any of these proceedings will have a material adverse effect on our financial condition, results of operations or cash flows.
	On a quarterly basis, we review our litigation activities and determine if an unfavorable outcome to us is considered “remote,” “reasonably possible” or “probable” as defined by U.S. GAAP. Where we determine an unfavorable outcome is probable and is reasonably estimable, we accrue for potential litigation losses. The liability we may ultimately incur with respect to such litigation matters, in the event of a negative outcome, may be in excess of amounts currently accrued, if any; however, we do not expect that the reasonably possible outcome of these litigation matters would, individually or in the aggregate, have a material adverse effect on our financial condition, results of operations or cash flows. Where we determine an unfavorable outcome is not probable or reasonably estimable, we do not accrue for any potential litigation loss. The ultimate outcome of these litigation matters cannot presently be determined, nor can the liability that could potentially result from a negative outcome be reasonably estimated. As a result, we give no assurance that such litigation matters would, individually or in the aggregate, not have a material adverse effect on our financial condition, results of operations or cash flows.
	Environmental Matters
	We are subject to complex and stringent environmental laws and regulations related to the operation of our power plants. On occasion, we may incur environmental fees, penalties and fines associated with the operation of our power plants. At the present time, we do not have environmental violations or other matters that would have a material impact on our financial condition, results of operations or cash flows or that would significantly change our operations.
	Bay Area Air Quality Management District (“BAAQMD”). On March 13, 2014, the Hearing Board of the BAAQMD entered into a stipulated conditional order for abatement agreed to by our Russell City Energy Company, LLC (“RCEC”) and the BAAQMD concerning a violation of the vendor-guaranteed water droplet drift rate for RCEC’s cooling tower discovered during initial performance testing. Under the stipulated order, RCEC is required to conduct testing to determine whether installing additional drift eliminators and/or new nozzles will cause the cooling tower to come into compliance with its vendor-guaranteed drift rate, and if the testing shows positive results, install the additional equipment in the cooling tower. The stipulated order specifies a schedule for RCEC to demonstrate compliance with the vendor-guaranteed drift rate and reserves the rights of BAAQMD to assert any penalty claims associated with this violation and of RCEC to assert any defenses to such claims in future proceedings.

Segment_and_Significant_Custom

Segment and Significant Customer Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment and Significant Customer Information	'
	Segment Information
	We assess our business on a regional basis due to the impact on our financial performance of the differing characteristics of these regions, particularly with respect to competition, regulation and other factors impacting supply and demand. At March 31, 2014, our reportable segments were West (including geothermal), Texas, North (including Canada) and Southeast. We continue to evaluate the optimal manner in which we assess our performance including our segments and future changes may result.
	Commodity Margin is a key operational measure reviewed by our chief operating decision maker to assess the performance of our segments. During the fourth quarter of 2013, we changed the methodology previously used during 2013 for allocating corporate expenses to our segments. This change had no impact on our Consolidated Condensed Statements of Operations for the three months ended March 31, 2013; however, segment amounts previously reported for the three months ended March 31, 2013 were adjusted by immaterial amounts. Our segment data for the three months ended March 31, 2013 has been recast to reflect this change. The tables below show our financial data for our segments for the periods indicated (in millions).
		Three Months Ended March 31, 2014
		West			Texas			North			Southeast			Consolidation			Total
														and
														Elimination
	Revenues from external customers	$	491		$	647		$	639		$	188		$	—		$	1,965
	Intersegment revenues	2			12			15			81			(110		)	—
	Total operating revenues	$	493		$	659		$	654		$	269		$	(110	)	$	1,965
	Commodity Margin	$	202		$	121		$	267		$	55		$	—		$	645
	Add: Unrealized mark-to-market commodity activity, net and other(1)	29			(46		)	(17		)	6			(9		)	(37		)
	Less:
	Plant operating expense	105			90			52			27			(9		)	265
	Depreciation and amortization expense	60			42			33			18			—			153
	Sales, general and other administrative expense	10			12			6			6			(1		)	33
	Other operating expenses	12			2			6			1			1			22
	(Income) from unconsolidated investments in power plants	—			—			(9		)	—			—			(9		)
	Income (loss) from operations	44			(71		)	162			9			—			144
	Interest expense, net of interest income																165
	Other (income) expense, net																11
	Loss before income taxes																$	(32	)
		Three Months Ended March 31, 2013
		West			Texas			North			Southeast			Consolidation			Total
														and
														Elimination
	Revenues from external customers	$	383		$	407		$	306		$	145		$	—		$	1,241
	Intersegment revenues	1			7			7			33			(48		)	—
	Total operating revenues	$	384		$	414		$	313		$	178		$	(48	)	$	1,241
	Commodity Margin	$	202		$	76		$	142		$	41		$	—		$	461
	Add: Unrealized mark-to-market commodity activity, net and other(1)	(37		)	(11		)	7			7			(7		)	(41		)
	Less:
	Plant operating expense	95			65			43			31			(7		)	227
	Depreciation and amortization expense	53			42			33			19			(1		)	146
	Sales, general and other administrative expense	7			14			6			6			—			33
	Other operating expenses	9			1			7			1			—			18
	(Income) from unconsolidated investments in power plants	—			—			(8		)	—			—			(8		)
	Income (loss) from operations	1			(57		)	68			(9		)	1			4
	Interest expense, net of interest income																174
	Other (income) expense, net																5
	Loss before income taxes																$	(175	)
	_________
	-1	Includes $(29) million and $(16) million of lease levelization and $4 million and $4 million of amortization expense for the three months ended March 31, 2014 and 2013, respectively.

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis of Interim Presentation	'
	Basis of Interim Presentation — The accompanying unaudited, interim Consolidated Condensed Financial Statements of Calpine Corporation, a Delaware corporation, and consolidated subsidiaries have been prepared pursuant to the rules and regulations of the SEC. In the opinion of management, the Consolidated Condensed Financial Statements include the normal, recurring adjustments necessary for a fair statement of the information required to be set forth therein. Certain information and note disclosures, normally included in financial statements prepared in accordance with U.S. GAAP, have been condensed or omitted from these statements pursuant to such rules and regulations and, accordingly, these financial statements should be read in conjunction with our audited Consolidated Financial Statements for the year ended December 31, 2013, included in our 2013 Form 10-K. The results for interim periods are not necessarily indicative of the results for the entire year primarily due to acquisitions and disposals of assets, seasonal fluctuations in our revenues, timing of major maintenance expense, variations resulting from the application of the method to calculate the provision for income tax for interim periods, volatility of commodity prices and unrealized gains and losses from commodity and interest rate derivative contracts.
Use of Estimates in Preparation of Financial Statements	'
	Use of Estimates in Preparation of Financial Statements — The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures included in our Consolidated Condensed Financial Statements. Actual results could differ from those estimates.
Reclassifications	'
	Reclassifications — We have reclassified certain prior year amounts for comparative purposes. These reclassifications did not have a material impact on our financial condition, results of operations or cash flows.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents — We consider all highly liquid investments with an original maturity of three months or less to be cash equivalents. We have certain project finance facilities and lease agreements that require us to establish and maintain segregated cash accounts, which have been pledged as security in favor of the lenders under such project finance facilities, and the use of certain cash balances on deposit in such accounts is limited, at least temporarily, to the operations of the respective projects. At March 31, 2014 and December 31, 2013, we had cash and cash equivalents of $98 million and $292 million, respectively, that were subject to such project finance facilities and lease agreements.
Restricted Cash	'
	Restricted Cash — Certain of our debt agreements, lease agreements or other operating agreements require us to establish and maintain segregated cash accounts, the use of which is restricted. These amounts are held by depository banks in order to comply with the contractual provisions requiring reserves for payments such as for debt service, rent, major maintenance and debt repurchases or with applicable regulatory requirements. Funds that can be used to satisfy obligations due during the next 12 months are classified as current restricted cash, with the remainder classified as non-current restricted cash. Restricted cash is generally invested in accounts earning market rates; therefore, the carrying value approximates fair value. Such cash is excluded from cash and cash equivalents on our Consolidated Condensed Balance Sheets and Statements of Cash Flows.
Inventory	'
	Inventory — At March 31, 2014 and December 31, 2013, we had inventory of $361 million and $364 million, respectively. Inventory primarily consists of spare parts, stored natural gas and fuel oil, environmental products and natural gas exchange imbalances. Inventory, other than spare parts, is stated primarily at the lower of cost or market value under the weighted average cost method. Spare parts inventory is valued at weighted average cost and is expensed to plant operating expense or capitalized to property, plant and equipment as the parts are utilized and consumed.
Derivatives	'
	Accounting for Derivative Instruments
	We recognize all derivative instruments that qualify for derivative accounting treatment as either assets or liabilities and measure those instruments at fair value unless they qualify for, and we elect, the normal purchase normal sale exemption. For transactions in which we elect the normal purchase normal sale exemption, gains and losses are not reflected on our Consolidated Condensed Statements of Operations until the period of delivery. Revenues and fuel costs derived from instruments that qualified for hedge accounting or represent an economic hedge are recorded in the same financial statement line item as the item being hedged. Hedge accounting requires us to formally document, designate and assess the effectiveness of transactions that receive hedge accounting. We present the cash flows from our derivatives in the same category as the item being hedged (or economically hedged) within operating activities or investing activities on our Consolidated Condensed Statements of Cash Flows unless they contain an other-than-insignificant financing element in which case their cash flows are classified within financing activities.
	Cash Flow Hedges — We report the effective portion of the unrealized gain or loss on a derivative instrument designated and qualifying as a cash flow hedging instrument as a component of OCI and reclassify such gains and losses into earnings in the same period during which the hedged forecasted transaction affects earnings. During the three months ended March 31, 2014 and 2013, we did not have any commodity derivative instruments designated as cash flow hedges. Gains and losses due to ineffectiveness on interest rate hedging instruments are recognized currently in earnings as a component of interest expense. If it is determined that the forecasted transaction is no longer probable of occurring, then hedge accounting will be discontinued prospectively and future changes in fair value are recorded in earnings. If the hedging instrument is terminated or de-designated prior to the occurrence of the hedged forecasted transaction, the net accumulated gain or loss associated with the changes in fair value of the hedge instrument remains deferred in AOCI until such time as the forecasted transaction impacts earnings or until it is determined that the forecasted transaction is probable of not occurring.
	Derivatives Not Designated as Hedging Instruments — We enter into power, natural gas, interest rate and environmental product transactions that primarily act as economic hedges to our asset and interest rate portfolio, but either do not qualify as hedges under the hedge accounting guidelines or qualify under the hedge accounting guidelines and the hedge accounting designation has not been elected. Changes in fair value of commodity derivatives not designated as hedging instruments are recognized currently in earnings and are separately stated on our Consolidated Condensed Statements of Operations in unrealized mark-to-market gain/loss as a component of operating revenues (for power and environmental product contracts and Heat Rate swaps and options) and fuel and purchased energy expense (for natural gas contracts, swaps and options). Changes in fair value of interest rate derivatives not designated as hedging instruments are recognized currently in earnings as interest expense.
Commitments and Contingencies	'
	On a quarterly basis, we review our litigation activities and determine if an unfavorable outcome to us is considered “remote,” “reasonably possible” or “probable” as defined by U.S. GAAP. Where we determine an unfavorable outcome is probable and is reasonably estimable, we accrue for potential litigation losses. The liability we may ultimately incur with respect to such litigation matters, in the event of a negative outcome, may be in excess of amounts currently accrued, if any; however, we do not expect that the reasonably possible outcome of these litigation matters would, individually or in the aggregate, have a material adverse effect on our financial condition, results of operations or cash flows. Where we determine an unfavorable outcome is not probable or reasonably estimable, we do not accrue for any potential litigation loss. The ultimate outcome of these litigation matters cannot presently be determined, nor can the liability that could potentially result from a negative outcome be reasonably estimated. As a result, we give no assurance that such litigation matters would, individually or in the aggregate, not have a material adverse effect on our financial condition, results of operations or cash flows.

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Schedule of Components of Restricted Cash	'
	The table below represents the components of our restricted cash as of March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014						December 31, 2013
		Current		Non-Current		Total		Current		Non-Current		Total
	Debt service(1)	$	11	$	41	$	52	$	11	$	41	$	52
	Rent reserve	4		—		4		3		—		3
	Construction/major maintenance	34		22		56		35		20		55
	Security/project/insurance	146		6		152		151		6		157
	Other	—		2		2		3		2		5
	Total	$	195	$	71	$	266	$	203	$	69	$	272
	___________
	-1	At both March 31, 2014 and December 31, 2013, amounts restricted for debt service included approximately $24 million of repurchase agreements with a financial institution containing maturity dates greater than one year.
Schedule of Property, Plant and Equipment	'
	Property, Plant and Equipment, Net — At March 31, 2014 and December 31, 2013, the components of property, plant and equipment are stated at cost less accumulated depreciation as follows (in millions):
		March 31, 2014		31-Dec-13		Depreciable Lives
	Buildings, machinery and equipment(1)	$	16,516	$	15,838	3 – 47 Years
	Geothermal properties	1,267		1,265		13 – 59 Years
	Other	167		164		3 – 47 Years
		17,950		17,267
	Less: Accumulated depreciation	5,046		4,897
		12,904		12,370
	Land	109		103
	Construction in progress	585		522
	Property, plant and equipment, net	$	13,598	$	12,995

Acquisition_Tables

Acquisition (Tables)	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Six Power Plants To be disposed of [Table Text Block]	'
	The six power plants included in the transaction are as follows:
	Plant Name		Plant Capacity		Location
	Oneta Energy Center		1,134	MW	Broken Arrow, OK
	Carville Energy Center(1)		501	MW	St. Gabriel, LA
	Decatur Energy Center		795	MW	Decatur, AL
	Hog Bayou Energy Center		237	MW	Mobile, AL
	Santa Rosa Energy Center		225	MW	Pace, FL
	Columbia Energy Center(1)		606	MW	Calhoun County, SC
	Total		3,498	MW
	___________
	-1	Indicates combined-cycle cogeneration power plant.

Variable_Interest_Entities_and1

Variable Interest Entities and Unconsolidated Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Variable Interest Entities and Unconsolidated Investments [Abstract]	'
Income (Loss) From Unconsolidated Investments in Power Plants	'
	Our equity interest in the net income from Greenfield LP and Whitby for the three months ended March 31, 2014 and 2013, is recorded in (income) from unconsolidated investments in power plants. The following table sets forth details of our (income) from unconsolidated investments in power plants for the periods indicated (in millions):
		Three Months Ended March 31,
		2014				2013
	Greenfield LP	$	(5	)		$	(4	)
	Whitby	(4		)		(4		)
	Total	$	(9	)		$	(8	)
Schedule of Equity Method Investments	'
	At March 31, 2014 and December 31, 2013, our equity method investments included on our Consolidated Condensed Balance Sheets were comprised of the following (in millions):
		Ownership Interest as of		March 31, 2014				December 31, 2013
		31-Mar-14
	Greenfield LP	50%		$	77			$	76
	Whitby	50%		8				17
	Total investments in power plants			$	85			$	93

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Schedule of Long-term Debt Instruments	'
	At March 31, 2014 and December 31, 2013, our debt was as follows (in millions):
		March 31, 2014		December 31, 2013
	First Lien Notes	$	4,989	$	4,989
	First Lien Term Loans	2,821		2,828
	Project financing, notes payable and other	1,865		1,901
	CCFC Term Loans	1,607		1,191
	Capital lease obligations	193		203
	Subtotal	11,475		11,112
	Less: Current maturities	189		204
	Total long-term debt	$	11,286	$	10,908
First Lien Notes	'
	Our First Lien Notes are summarized in the table below (in millions):
		March 31, 2014		December 31, 2013
	2019 First Lien Notes	$	320	$	320
	2020 First Lien Notes	875		875
	2021 First Lien Notes	1,600		1,600
	2022 First Lien Notes	744		744
	2023 First Lien Notes	960		960
	2024 First Lien Notes	490		490
	Total First Lien Notes	$	4,989	$	4,989
First Lien Term Loans	'
	Our First Lien Term Loans are summarized in the table below (in millions):
		March 31, 2014		December 31, 2013
	2018 First Lien Term Loans	$	1,610	$	1,614
	2019 First Lien Term Loan	822		824
	2020 First Lien Term Loan	389		390
	Total First Lien Term Loans	$	2,821	$	2,828
Schedule of Line of Credit Facilities	'
	The table below represents amounts issued under our letter of credit facilities at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Corporate Revolving Facility(1)	$	239	$	242
	CDHI	240		218
	Various project financing facilities	170		170
	Total	$	649	$	630
	____________
	-1	The Corporate Revolving Facility represents our primary revolving facility.
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	'
	The following table details the fair values and carrying values of our debt instruments at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014				December 31, 2013
		Fair Value		Carrying		Fair Value		Carrying
				Value				Value
	First Lien Notes	$	5,418	$	4,989	$	5,317	$	4,989
	First Lien Term Loans	2,826		2,821		2,845		2,828
	Project financing, notes payable and other(1)	1,751		1,743		1,772		1,766
	CCFC Term Loans	1,590		1,607		1,179		1,191
	Total	$	11,585	$	11,160	$	11,113	$	10,774
	____________
	-1	Excludes a lease that is accounted for as a failed sale-leaseback transaction under U.S. GAAP.

Assets_and_Liabilities_with_Re1

Assets and Liabilities with Recurring Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Measurements [Abstract]	'
Fair Value, Measurement Inputs, Disclosure	'
	Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect our estimate of the fair value of our assets and liabilities and their placement within the fair value hierarchy levels. The following tables present our financial assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2014 and December 31, 2013, by level within the fair value hierarchy:
		Assets and Liabilities with Recurring Fair Value Measures as of March 31, 2014
		Level 1			Level 2				Level 3		Total
		(in millions)
	Assets:
	Cash equivalents(1)	$	717		$	—			$	—	$	717
	Margin deposits	235			—				—		235
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	717			—				—		717
	Commodity forward contracts(2)	—			69				36		105
	Interest rate swaps	—			7				—		7
	Total assets	$	1,669		$	76			$	36	$	1,781
	Liabilities:
	Margin deposits posted with us by our counterparties	$	18		$	—			$	—	$	18
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	684			—				—		684
	Commodity forward contracts(2)	—			120				28		148
	Interest rate swaps	—			126				—		126
	Total liabilities	$	702		$	246			$	28	$	976
		Assets and Liabilities with Recurring Fair Value Measures as of December 31, 2013
		Level 1			Level 2				Level 3		Total
		(in millions)
	Assets:
	Cash equivalents(1)	$	1,134		$	—			$	—	$	1,134
	Margin deposits	261			—				—		261
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	434			—				—		434
	Commodity forward contracts(2)	—			75				32		107
	Interest rate swaps	—			9				—		9
	Total assets	$	1,829		$	84			$	32	$	1,945
	Liabilities:
	Margin deposits posted with us by our counterparties	$	5		$	—			$	—	$	5
	Commodity instruments:
	Commodity exchange traded futures and swaps contracts	495			—				—		495
	Commodity forward contracts(2)	—			52				18		70
	Interest rate swaps	—			129				—		129
	Total liabilities	$	500		$	181			$	18	$	699
	___________
	-1	As of March 31, 2014 and December 31, 2013, we had cash equivalents of $478 million and $889 million included in cash and cash equivalents and $239 million and $245 million included in restricted cash, respectively.
	-2	Includes OTC swaps and options.
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 March 31, 2014 and December 31, 2013:
			Quantitative Information about Level 3 Fair Value Measurements
			31-Mar-14
			Fair Value, Net Asset					Significant Unobservable
			(Liability)			Valuation Technique		Input		Range
			(in millions)
	Power Congestion Products		$	7		Discounted cash flow		Market price (per MWh)		$(8.79) — $11.53/MWh
			31-Dec-13
			Fair Value, Net Asset					Significant Unobservable
			(Liability)			Valuation Technique		Input		Range
			(in millions)
	Physical Power		$	7		Discounted cash flow		Market price (per MWh)		$28.92 — $53.15/MWh
	Power Congestion Products		$	7		Discounted cash flow		Market price (per MWh)		$(8.79) — $11.53/MWh
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	'
	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 March 31,
		2014			2013
	Balance, beginning of period	$	14		$	16
	Realized and unrealized gains (losses):
	Included in net loss:
	Included in operating revenues(1)	(10		)	1
	Included in fuel and purchased energy expense(2)	5			—
	Purchases and settlements:
	Purchases	1			—
	Settlements	(3		)	(3		)
	Transfers in and/or out of level 3(3):
	Transfers into level 3(4)	—			—
	Transfers out of level 3(5)	1			(1		)
	Balance, end of period	$	8		$	13
	Change in unrealized gains (losses) relating to instruments still held at end of period	$	(5	)	$	1
	___________
	-1	For power contracts and other power-related products, included on our Consolidated Condensed Statements of Operations.
	-2	For natural gas 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 months ended March 31, 2014 and 2013.
	-4	There were no transfers out of level 2 into level 3 for each of the three months ended March 31, 2014 and 2013.
	-5	We had $1 million in losses and $1 million in gains transferred out of level 3 into level 2 for the three months ended March 31, 2014 and 2013, respectively, due to changes in market liquidity in various power markets.

Derivative_Instruments_Tables

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments [Abstract]	'
Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block]	'
	The following tables present the fair values of our derivative instruments recorded on our Consolidated Condensed Balance Sheets by location and hedge type at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014
		Commodity				Interest Rate				Total
		Instruments				Swaps				Derivative
										Instruments
	Balance Sheet Presentation
	Current derivative assets	$	655			$	—			$	655
	Long-term derivative assets	167				7				174
	Total derivative assets	$	822			$	7			$	829
	Current derivative liabilities	$	681			$	47			$	728
	Long-term derivative liabilities	151				79				230
	Total derivative liabilities	$	832			$	126			$	958
	Net derivative liabilities	$	(10	)		$	(119	)		$	(129	)
		December 31, 2013
		Commodity				Interest Rate				Total
		Instruments				Swaps				Derivative
										Instruments
	Balance Sheet Presentation
	Current derivative assets	$	445			$	—			$	445
	Long-term derivative assets	96				9				105
	Total derivative assets	$	541			$	9			$	550
	Current derivative liabilities	$	404			$	47			$	451
	Long-term derivative liabilities	161				82				243
	Total derivative liabilities	$	565			$	129			$	694
	Net derivative liabilities	$	(24	)		$	(120	)		$	(144	)
Schedule of Notional Amounts of Outstanding Derivative Positions	'
	As of March 31, 2014 and December 31, 2013, the net forward notional buy (sell) position of our outstanding commodity and interest rate swap contracts that did not qualify or were not designated under the normal purchase normal sale exemption were as follows (in millions):
	Derivative Instruments		Notional Amounts
			March 31, 2014				December 31, 2013
	Power (MWh)		(29		)		(29		)
	Natural gas (MMBtu)		541				448
	Environmental credits (Tonnes)		2				—
	Interest rate swaps		$	1,517			$	1,527
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	'
		March 31, 2014								December 31, 2013
		Fair Value				Fair Value				Fair Value				Fair Value
		of Derivative				of Derivative				of Derivative				of Derivative
		Assets				Liabilities				Assets				Liabilities
	Derivatives designated as cash flow hedging instruments:
	Interest rate swaps	$	7			$	113			$	9			$	115
	Total derivatives designated as cash flow hedging instruments	$	7			$	113			$	9			$	115
	Derivatives not designated as hedging instruments:
	Commodity instruments	$	822			$	832			$	541			$	565
	Interest rate swaps	—				13				—				14
	Total derivatives not designated as hedging instruments	$	822			$	845			$	541			$	579
	Total derivatives	$	829			$	958			$	550			$	694
Derivative Instruments Subject to Master Netting Arrangements [Table Text Block]	'
	The tables below set forth our net exposure to derivative instruments after offsetting amounts subject to a master netting arrangement with the same counterparty at March 31, 2014 and December 31, 2013 (in millions):
			March 31, 2014
			Gross Amounts Not Offset on the Consolidated Condensed Balance Sheets
			Gross Amounts Presented on our Consolidated Condensed Balance Sheets				Derivative Asset (Liability) not Offset on the Consolidated Condensed Balance Sheets				Margin/Cash (Received) Posted (1)				Net Amount
	Derivative assets:
	Commodity exchange traded futures and swaps contracts		$	717			$	(669	)		$	(48	)		$	—
	Commodity forward contracts		105				(78		)		—				27
	Interest rate swaps		7				—				—				7
	Total derivative assets		$	829			$	(747	)		$	(48	)		$	34
	Derivative (liabilities):
	Commodity exchange traded futures and swaps contracts		$	(684	)		$	669			$	15			$	—
	Commodity forward contracts		(148		)		78				7				(63		)
	Interest rate swaps		(126		)		—				—				(126		)
	Total derivative (liabilities)		$	(958	)		$	747			$	22			$	(189	)
	Net derivative assets (liabilities)		$	(129	)		$	—			$	(26	)		$	(155	)
			31-Dec-13
			Gross Amounts Not Offset on the Consolidated Condensed Balance Sheets
			Gross Amounts Presented on our Consolidated Condensed Balance Sheets				Derivative Asset (Liability) not Offset on the Consolidated Condensed Balance Sheets				Margin/Cash (Received) Posted (1)				Net Amount
	Derivative assets:
	Commodity exchange traded futures and swaps contracts		$	434			$	(420	)		$	(14	)		$	—
	Commodity forward contracts		107				(60		)		—				47
	Interest rate swaps		9				—				—				9
	Total derivative assets		$	550			$	(480	)		$	(14	)		$	56
	Derivative (liabilities):
	Commodity exchange traded futures and swaps contracts		$	(495	)		$	420			$	75			$	—
	Commodity forward contracts		(70		)		60				1				(9		)
	Interest rate swaps		(129		)		—				—				(129		)
	Total derivative (liabilities)		$	(694	)		$	480			$	76			$	(138	)
	Net derivative assets (liabilities)		$	(144	)		$	—			$	62			$	(82	)
	____________
	-1	Negative balances represent margin deposits posted with us by our counterparties related to our derivative activities that are subject to a master netting arrangement. Positive balances reflect margin deposits posted by us with our counterparties related to our derivative activities that are subject to a master netting arrangement. See Note 7 for a further discussion of our collateral.
Realized Unrealized Gain Loss by Instrument	'
	The following tables detail the components of our total mark-to-market activity for both the net realized gain (loss) and the net unrealized gain (loss) recognized from our derivative instruments in earnings and where these components were recorded on our Consolidated Condensed Statements of Operations for the periods indicated (in millions):
		Three Months Ended March 31,
		2014				2013
	Realized gain (loss)(1)
	Commodity derivative instruments	$	(39	)		$	28
	Total realized gain (loss)	$	(39	)		$	28
	Unrealized gain (loss)(2)
	Commodity derivative instruments	$	(73	)		$	(57	)
	Interest rate swaps	1				2
	Total unrealized gain (loss)	$	(72	)		$	(55	)
	Total mark-to-market activity, net	$	(111	)		$	(27	)
	___________
	-1	Does not include the realized value associated with derivative instruments that settle through physical delivery.
	-2	In addition to changes in market value on derivatives not designated as hedges, changes in unrealized gain (loss) also includes de-designation of interest rate swap cash flow hedges and related reclassification from AOCI into earnings, hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	'
		Three Months Ended March 31,
		2014				2013
	Realized and unrealized gain (loss)
	Derivatives contracts included in operating revenues	$	(237	)		$	(74	)
	Derivatives contracts included in fuel and purchased energy expense	125				45
	Interest rate swaps included in interest expense	1				2
	Total mark-to-market activity, net	$	(111	)		$	(27	)
Derivatives Designated as Hedges	'
	The following table details the effect of our net derivative instruments that qualified for hedge accounting treatment and are included in OCI and AOCI for the periods indicated (in millions):
		Three Months Ended March 31,								Three Months Ended March 31,
		Gain (Loss) Recognized  in								Gain (Loss) Reclassified from
		OCI (Effective Portion)								AOCI into Income (Effective Portion)(3)
		2014				2013				2014				2013				Affected Line Item on the Consolidated Condensed Statements of Operations
	Interest rate swaps(1)	$	—			$	13			$	(13	)	(4)	$	(9	)		Interest expense
	Total(2)	$	—			$	13			$	(13	)		$	(9	)
	____________
	-1	We did not record any gain (loss) on hedge ineffectiveness related to our interest rate swaps designated as cash flow hedges during the three months ended March 31, 2014 and 2013.
	-2	We recorded an income tax benefit of nil and $1 million for the three months ended March 31, 2014 and 2013, respectively, in AOCI related to our cash flow hedging activities.
	-3	Cumulative cash flow hedge losses attributable to Calpine, net of tax, remaining in AOCI were $148 million at each of March 31, 2014 and December 31, 2013. Cumulative cash flow hedge losses attributable to the noncontrolling interest, net of tax, remaining in AOCI were $11 million at each of March 31, 2014 and December 31, 2013.
	-4	Includes a loss of $5 million that was reclassified from AOCI to interest expense for the three months ended March 31, 2014 where the hedged transactions are no longer expected to occur.

Use_of_Collateral_Tables

Use of Collateral (Tables)	3 Months Ended
	Mar. 31, 2014
Use of Collateral [Abstract]	'
Schedule of Collateral	'
	The table below summarizes the balances outstanding under margin deposits, natural gas and power prepayments, and exposure under letters of credit and first priority liens for commodity procurement and risk management activities as of March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Margin deposits(1)	$	235	$	261
	Natural gas and power prepayments	29		28
	Total margin deposits and natural gas and power prepayments with our counterparties(2)	$	264	$	289
	Letters of credit issued	$	536	$	488
	First priority liens under power and natural gas agreements	24		31
	First priority liens under interest rate swap agreements	128		132
	Total letters of credit and first priority liens with our counterparties	$	688	$	651
	Margin deposits posted with us by our counterparties(1)(3)	$	18	$	5
	Letters of credit posted with us by our counterparties	2		2
	Total margin deposits and letters of credit posted with us by our counterparties	$	20	$	7
	___________
	-1	Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.
	-2	At March 31, 2014 and December 31, 2013, $249 million and $272 million, respectively, were included in margin deposits and other prepaid expense and $15 million and $17 million, respectively, were included in other assets on our Consolidated Condensed Balance Sheets.
	-3	Included in other current liabilities on our Consolidated Condensed Balance Sheets.

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit)	'
	The table below shows our consolidated income tax benefit from continuing operations (excluding noncontrolling interest) and our effective tax rates for the periods indicated (in millions):
		Three Months Ended March 31,
		2014			2013
	Income tax benefit	$	(19	)	$	(50	)
	Effective tax rate	53		%	29		%

Earnings_Loss_per_Share_Tables

Earnings (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings (Loss) per Share [Abstract]	'
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	'
	We excluded the following items from diluted loss per common share for the three months ended March 31, 2014 and 2013, because they were anti-dilutive (shares in thousands):
		Three Months Ended March 31,
		2014	2013
	Share-based awards	8,995	10,963

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Compensation, Activity [Table Text Block]	'
	A summary of our performance share unit activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted
		Performance Share Units			Average
					Grant-Date
					Fair Value
	Nonvested — December 31, 2013	449,798			$	21.25
	Granted	461,393			$	22.56
	Forfeited	—			$	—
	Vested	15,312		(1)	$	21.25
	Nonvested — March 31, 2014	895,879			$	21.92
	___________
	-1	In accordance with the applicable performance share unit agreements, performance share units granted to employees who meet the retirement eligibility requirements stipulated in the Equity Plan are fully vested upon the later of the date on which the employee becomes eligible to retire or one-year anniversary of the grant date.
Schedule of Non-Qualified Stock Option Activity	'
	A summary of all of our non-qualified stock option activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted Average		Weighted	Aggregate
		Shares			Exercise Price		Average	Intrinsic Value
							Remaining	(in millions)
							Term
							(in years)
	Outstanding — December 31, 2013	14,114,289			$	18.25	3.1	$	36
	Granted	—			$	—
	Exercised	184,931			$	15.56
	Forfeited	—			$	—
	Expired	1,500			$	17.39
	Outstanding — March 31, 2014	13,927,858			$	18.29	2.8	$	48
	Exercisable — March 31, 2014	13,012,308			$	18.5	2.5	$	43
	Vested and expected to vest – March 31, 2014	13,871,693			$	18.3	2.8	$	48
Schedule of Assumptions Used to Estimate Fair Value for Options	'
	Certain assumptions were used in order to estimate fair value for options as noted in the following table:
		2013
	Expected term (in years)(1)	6.5
	Risk-free interest rate(2)	1.4			%
	Expected volatility(3)	25.6			%
	Dividend yield(4)	—
	Weighted average grant-date fair value (per option)	$	5.31
	___________
	-1	Expected term calculated using the simplified method prescribed by the SEC due to the lack of sufficient historical exercise data on the grant date to provide a reasonable basis to estimate the expected term.
	-2	Zero Coupon U.S. Treasury rate or equivalent based on expected term.
	-3	Volatility calculated using the implied volatility of our exchange traded stock options.
	-4	We have never paid cash dividends on our common stock, and we do not anticipate any cash dividend payments on our common stock in the near future.
Schedule of Restricted Stock and Restricted Stock Unit Activity	'
	A summary of our restricted stock and restricted stock unit activity for the three months ended March 31, 2014, is as follows:
		Number of			Weighted
		Restricted			Average
		Stock Awards			Grant-Date
					Fair Value
	Nonvested — December 31, 2013	4,431,841			$	16.45
	Granted	1,764,446			$	19.11
	Forfeited	25,977			$	17.03
	Vested	1,434,614			$	15.07
	Nonvested — March 31, 2014	4,735,696			$	17.86

Segment_and_Significant_Custom1

Segment and Significant Customer Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Schedule of Financial Data for Segments	'
	The tables below show our financial data for our segments for the periods indicated (in millions).
		Three Months Ended March 31, 2014
		West			Texas			North			Southeast			Consolidation			Total
														and
														Elimination
	Revenues from external customers	$	491		$	647		$	639		$	188		$	—		$	1,965
	Intersegment revenues	2			12			15			81			(110		)	—
	Total operating revenues	$	493		$	659		$	654		$	269		$	(110	)	$	1,965
	Commodity Margin	$	202		$	121		$	267		$	55		$	—		$	645
	Add: Unrealized mark-to-market commodity activity, net and other(1)	29			(46		)	(17		)	6			(9		)	(37		)
	Less:
	Plant operating expense	105			90			52			27			(9		)	265
	Depreciation and amortization expense	60			42			33			18			—			153
	Sales, general and other administrative expense	10			12			6			6			(1		)	33
	Other operating expenses	12			2			6			1			1			22
	(Income) from unconsolidated investments in power plants	—			—			(9		)	—			—			(9		)
	Income (loss) from operations	44			(71		)	162			9			—			144
	Interest expense, net of interest income																165
	Other (income) expense, net																11
	Loss before income taxes																$	(32	)
		Three Months Ended March 31, 2013
		West			Texas			North			Southeast			Consolidation			Total
														and
														Elimination
	Revenues from external customers	$	383		$	407		$	306		$	145		$	—		$	1,241
	Intersegment revenues	1			7			7			33			(48		)	—
	Total operating revenues	$	384		$	414		$	313		$	178		$	(48	)	$	1,241
	Commodity Margin	$	202		$	76		$	142		$	41		$	—		$	461
	Add: Unrealized mark-to-market commodity activity, net and other(1)	(37		)	(11		)	7			7			(7		)	(41		)
	Less:
	Plant operating expense	95			65			43			31			(7		)	227
	Depreciation and amortization expense	53			42			33			19			(1		)	146
	Sales, general and other administrative expense	7			14			6			6			—			33
	Other operating expenses	9			1			7			1			—			18
	(Income) from unconsolidated investments in power plants	—			—			(8		)	—			—			(8		)
	Income (loss) from operations	1			(57		)	68			(9		)	1			4
	Interest expense, net of interest income																174
	Other (income) expense, net																5
	Loss before income taxes																$	(175	)
	_________
	-1	Includes $(29) million and $(16) million of lease levelization and $4 million and $4 million of amortization expense for the three months ended March 31, 2014 and 2013, respectively.

Basis_of_Presentation_and_Summ3

Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Accounting Policies [Line Items]	'		'	'
Current	$195		'	$203
Non-current	71		'	69
Total	266		'	272
Held-to-maturity Securities, Restricted	24		'	24
Cash and cash equivalents subject to project finance facilities and lease agreements	98		'	292
Interest Costs Capitalized	6		12	'
Inventory	361		'	364
Treasury Stock, Value, Acquired, Cost Method	140		'	'
Adjustments Related to Tax Withholding for Share-based Compensation	8		'	'
Debt Service	'		'	'
Accounting Policies [Line Items]	'		'	'
Current	11	[1]	'	11	[1]
Non-current	41	[1]	'	41	[1]
Total	52	[1]	'	52	[1]
Rent Reserve	'		'	'
Accounting Policies [Line Items]	'		'	'
Current	4		'	3
Non-current	0		'	0
Total	4		'	3
Construction Major Maintenance	'		'	'
Accounting Policies [Line Items]	'		'	'
Current	34		'	35
Non-current	22		'	20
Total	56		'	55
Security Project Insurance	'		'	'
Accounting Policies [Line Items]	'		'	'
Current	146		'	151
Non-current	6		'	6
Total	152		'	157
Other	'		'	'
Accounting Policies [Line Items]	'		'	'
Current	0		'	3
Non-current	2		'	2
Total	$2		'	$5
Geothermal Properties, Gross [Member] | Minimum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'13 years		'	'
Geothermal Properties, Gross [Member] | Maximum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'59 years		'	'
Property, Plant and Equipment, Other Types [Member] | Minimum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'3 years		'	'
Property, Plant and Equipment, Other Types [Member] | Maximum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'47 years		'	'
Building, Machinery and Equipment, Gross [Member] | Minimum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'3 years		'	'
Building, Machinery and Equipment, Gross [Member] | Maximum [Member]	'		'	'
Accounting Policies [Line Items]	'		'	'
Property, Plant and Equipment, Estimated Useful Lives	'47 years		'	'
[1]	At both March 31, 2014 and December 31, 2013, amounts restricted for debt service included approximately $24 million of repurchase agreements with a financial institution containing maturity dates greater than one year.

Basis_of_Presentation_and_Summ4

Basis of Presentation and Summary of Significant Accounting Policies Property, Plant and Equipment, Net (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Line Items]	'		'
Buildings, machinery and equipment	$16,516	[1]	$15,838	[1]
Geothermal properties	1,267		1,265
Other	167		164
Property, Plant and Equipment, Gross	17,950		17,267
Less: Accumulated depreciation	5,046		4,897
Property, Plant and Equipment, Gross, Less Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	12,904		12,370
Land	109		103
Construction in progress	585		522
Property, plant and equipment, net	$13,598		$12,995
[1]	(1)The change from December 31, 2013 to March 31, 2014 can primarily be attributed to our acquisition of Guadalupe Energy Center on February 26, 2014.

Acquisition_Details

Acquisition (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
	MW		MW
Business Acquisition [Line Items]	'		'
Number of power plants to be disposed of	'6		'
Ownership percentage before divestiture of business	100.00%		'
Proceeds from Sale of Productive Assets	$1,570,000,000		'
Power generation capacity	9,849		9,427
Number of 525 MW generation blocks to be acquired in the Guadalupe acquisition	'2		'
Guadalupe Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	1,050		'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	625,000,000		'
Guadalupe Expansion Capacity [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	400		'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	15,000,000		'
Incremental CCFC Term Loans [Member]	'		'
Business Acquisition [Line Items]	'		'
Debt Instrument, Face Amount	425,000,000		'
Oneta Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	1,134		'
Carville Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	501	[1]	'
Decatur Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	795		'
Hog Bayou Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	237		'
Santa Rosa Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	225		'
Columbia Energy Center [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	606	[1]	'
Six Power Plants [Member]	'		'
Business Acquisition [Line Items]	'		'
Power generation capacity	3,498		'
Minimum [Member]	'		'
Business Acquisition [Line Items]	'		'
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	725,000,000		'
Maximum [Member]	'		'
Business Acquisition [Line Items]	'		'
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	$775,000,000		'
[1]	Indicates combined-cycle cogeneration power plant.

Variable_Interest_Entities_and2

Variable Interest Entities and Unconsolidated Investments (Unconsolidated VIEs) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Schedule of Equity Method Investments [Line Items]	'	'
Equity Method Investments	$85	$93
Greenfield [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Equity Method Investments	77	76
Equity Method Investment, Ownership Percentage	50.00%	'
Whitby [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Equity Method Investments	$8	$17
Equity Method Investment, Ownership Percentage	50.00%	'

Variable_Interest_Entities_and3

Variable Interest Entities and Unconsolidated Investments (Income from Unconsolidated Investements 10-Q) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
(Income) from unconsolidated investments in power plants	($9)	($8)
Greenfield [Member]	'	'
(Income) from unconsolidated investments in power plants	-5	-4
Whitby [Member]	'	'
(Income) from unconsolidated investments in power plants	($4)	($4)

Variable_Interest_Entities_and4

Variable Interest Entities and Unconsolidated Investments (VIE Texuals) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	MW		MW
Variable Interest Entity [Line Items]	'	'	'
Power generation capacity	9,849	'	9,427
Variable Interest Entity, Financial or Other Support, Amount	$40	$0	'
Equity Method Investment, Summarized Financial Information, Debt	376	'	395
Prorata Share of Equity Method Investment, Summarized Financial Information, Debt	188	'	198
Greenfield [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Power generation capacity	1,038	'	'
Equity Method Investment, Ownership Percentage	50.00%	'	'
Distribution from equity method investee	0	0	'
Whitby [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Power generation capacity	50	'	'
Equity Method Investment, Ownership Percentage	50.00%	'	'
Distribution from equity method investee	$13	$0	'
Inland Empire Energy Center [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Power generation capacity	775	'	'
Put Option Exercise Period	2,025	'	'
Inland Empire Energy Center [Member] | Minimum [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Call Option Exercise Period	2,017	'	'
Inland Empire Energy Center [Member] | Maximum [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Call Option Exercise Period	2,024	'	'

Debt_Debt_Details

Debt (Debt) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Long-term Debt	$11,475	$11,112
Debt, Current	189	204
Long-term Debt, Excluding Current Maturities	11,286	10,908
Corporate Debt Securities [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	4,989	4,989
Loans Payable [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	2,821	2,828
Notes Payable, Other Payables [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	1,865	1,901
Secured Debt [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	1,607	1,191
Capital Lease Obligations [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	$193	$203

Debt_First_Lien_Notes_Details

Debt (First Lien Notes) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Long-term Debt	$11,475	$11,112
First Lien Notes 2019 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	320	320
First Lien Notes 2020 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	875	875
First Lien Notes 2021 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	1,600	1,600
2022 First Lien Notes [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	744	744
First Lien Notes 2023 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	960	960
2024 First Lien Notes [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	490	490
Corporate Debt Securities [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	$4,989	$4,989

Debt_First_Lien_Term_Loans_Det

Debt (First Lien Term Loans) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Long-term Debt	$11,475	$11,112
First Lien Term Loans 2018 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	1,610	1,614
First Lien Term Loan 2019 [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	822	824
2020 First Lien Term Loan [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	389	390
First Lien Term Loans [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term Debt	$2,821	$2,828

Debt_Letter_of_Credit_Details

Debt (Letter of Credit) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Line of Credit Facility [Line Items]	'		'
Letters of Credit Outstanding, Amount	$649		$630
Corporate Revolving Facility [Member]	'		'
Line of Credit Facility [Line Items]	'		'
Letters of Credit Outstanding, Amount	239	[1]	242	[1]
CDH [Member]	'		'
Line of Credit Facility [Line Items]	'		'
Letters of Credit Outstanding, Amount	240		218
Various Project Financing Facilities [Member]	'		'
Line of Credit Facility [Line Items]	'		'
Letters of Credit Outstanding, Amount	$170		$170
[1]	The Corporate Revolving Facility represents our primary revolving facility.

Debt_Fair_Value_of_Debt_Detail

Debt (Fair Value of Debt) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Portion at Fair Value, Fair Value Disclosure [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Notes Payable, Fair Value Disclosure	$5,418		$5,317
Loans Payable, Fair Value Disclosure	2,826		2,845
Notes Payable, Other Payables, Disclosure	1,751	[1]	1,772	[1]
Subsidiaries Term Loan	1,590		1,179
Debt Excluding Capital Leases	11,585		11,113
Carrying (Reported) Amount, Fair Value Disclosure [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Notes Payable, Fair Value Disclosure	4,989		4,989
Loans Payable, Fair Value Disclosure	2,821		2,828
Notes Payable, Other Payables, Disclosure	1,743	[1]	1,766	[1]
Subsidiaries Term Loan	1,607		1,191
Debt Excluding Capital Leases	$11,160		$10,774
[1]	Excludes a lease that is accounted for as a failed sale-leaseback transaction under U.S. GAAP.

Debt_Debt_Textuals_Details

Debt (Debt Textuals) (Details)	Mar. 31, 2014	Mar. 31, 2013
Debt Instrument [Line Items]	'	'
Debt Instrument, Interest Rate, Effective Percentage	6.20%	7.00%

Debt_CCFC_Term_Loans_Details

Debt CCFC Term Loans (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
CCFC Term Loan B-2 [Member]	'
Debt Instrument [Line Items]	'
Debt Instrument, Face Amount	$300
Incremental CCFC Term Loans [Member]	'
Debt Instrument [Line Items]	'
Debt Instrument, Face Amount	$425
Long Term Debt net of Original Issuance Disount	98.75%

Assets_and_Liabilities_with_Re2

Assets and Liabilities with Recurring Fair Value Measurements Fair Value Hierarchy (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Cash equivalents	$717	[1]	$1,134	[1]
Margin deposits	235	[2]	261	[2]
Commodity futures contracts	717		434
Commodity forward contracts	105	[3]	107	[3]
Interest Rate Swap Assets, Fair Value Disclosure	7		9
Total assets	1,781		1,945
Margin deposits held by us posted by our counterparties	18	[2],[4]	5	[2],[4]
Commodity futures contracts	684		495
Commodity forward contracts	148	[3]	70	[3]
Interest rate swaps	126		129
Liabilities, Fair Value Disclosure	976		699
Fair Value, Inputs, Level 1 [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Cash equivalents	717	[1]	1,134	[1]
Margin deposits	235		261
Commodity futures contracts	717		434
Commodity forward contracts	0	[3]	0	[3]
Interest Rate Swap Assets, Fair Value Disclosure	0		0
Total assets	1,669		1,829
Margin deposits held by us posted by our counterparties	18		5
Commodity futures contracts	684		495
Commodity forward contracts	0	[3]	0	[3]
Interest rate swaps	0		0
Liabilities, Fair Value Disclosure	702		500
Fair Value, Inputs, Level 2 [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Cash equivalents	0	[1]	0	[1]
Margin deposits	0		0
Commodity futures contracts	0		0
Commodity forward contracts	69	[3]	75	[3]
Interest Rate Swap Assets, Fair Value Disclosure	7		9
Total assets	76		84
Margin deposits held by us posted by our counterparties	0		0
Commodity futures contracts	0		0
Commodity forward contracts	120	[3]	52	[3]
Interest rate swaps	126		129
Liabilities, Fair Value Disclosure	246		181
Fair Value, Inputs, Level 3 [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Cash equivalents	0	[1]	0	[1]
Margin deposits	0		0
Commodity futures contracts	0		0
Commodity forward contracts	36	[3]	32	[3]
Interest Rate Swap Assets, Fair Value Disclosure	0		0
Total assets	36		32
Margin deposits held by us posted by our counterparties	0		0
Commodity futures contracts	0		0
Commodity forward contracts	28	[3]	18	[3]
Interest rate swaps	0		0
Liabilities, Fair Value Disclosure	$28		$18
[1]	As of March 31, 2014 and December 31, 2013, we had cash equivalents of $478 million and $889 million included in cash and cash equivalents and $239 million and $245 million included in restricted cash, respectively.
[2]	Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.
[3]	Includes OTC swaps and options.
[4]	Included in other current liabilities on our Consolidated Condensed Balance Sheets.

Assets_and_Liabilities_with_Re3

Assets and Liabilities with Recurring Fair Value Measurements (Textuals) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Balance, beginning of period	$14		$16		'
Included in net income:	'		'		'
Included in operating revenues	-10	[1]	1	[1]	'
Fair Value, Assets Measured with Unobservable Inputs on Recurring Basis, Gain (Loss) Included In Fuel And Purchased Energy Expense	5	[2]	0	[2]	'
Purchases, issuances and settlements:	'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	1		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-3		-3		'
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount	0		0		'
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount	0		0		'
Transfers into level 3	0	[3],[4]	0	[3],[4]	'
Transfers out of Level 3	1	[4],[5]	-1	[4],[5]	'
Balance, end of period	8		13		'
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	-5		1		'
Assets and Liabilities with Recurring Fair Value Measurements (Textuals) [Abstract]	'		'		'
Cash Equivalents Included In Cash And Cash Equivalents, Fair Value Disclosure	478		'		889
Cash Equivalents Included In Restricted Cash, Fair Value Disclosure	$239		'		$245
[1]	For power contracts and other power-related products, included on our Consolidated Condensed Statements of Operations.
[2]	For natural gas contracts, swaps and options, included on our Consolidated Condensed Statements of Operations.
[3]	There were no transfers out of level 2 into level 3 for each of the three months ended March 31, 2014 and 2013.
[4]	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 months ended March 31, 2014 and 2013.
[5]	We had $1 million in losses and $1 million in gains transferred out of level 3 into level 2 for the three months ended March 31, 2014 and 2013, respectively, due to changes in market liquidity in various power markets.

Assets_and_Liabilities_with_Re4

Assets and Liabilities with Recurring Fair Value Measurements Quantitative Info on Level 3 (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Physical Power [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	'	$7,000,000
Physical Power [Member] | Minimum [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	'	28.92
Physical Power [Member] | Maximum [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	'	53.15
Power Congestion Products [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	7,000,000	7,000,000
Power Congestion Products [Member] | Minimum [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	-8.79	-8.79
Power Congestion Products [Member] | Maximum [Member]	'	'
Fair Value Inputs, Assets, Quantitative Information [Line Items]	'	'
Fair Value Inputs Quantitative Information Power	$11.53	$11.53

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
	t	t
	MWh	MWh
	MMBTU	MMBTU
Derivative Instruments [Abstract]	'	'
Derivative, Nonmonetary Notional Amount, Energy Measure	-29	-29
Nonmonetary Notional Amount of Price Risk Derivatives Natural Gas	541	448
Derivative, Nonmonetary Notional Amount, Mass	2	0
Price Risk Derivatives [Abstract]	'	'
Derivative, Notional Amount	$1,517	$1,527

Derivative_Instruments_Details1

Derivative Instruments (Details 2) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, current	$655	$445
Derivative Assets, Noncurrent	174	105
Total derivative assets	829	550
Current derivative liabilities	728	451
Derivative Liabilities, Noncurrent	230	243
Total derivative liabilities	958	694
Net derivative assets (liabilities)	-129	-144
Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	7	9
Total derivative liabilities	113	115
Not Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	822	541
Total derivative liabilities	845	579
Interest Rate Swap [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, current	0	0
Derivative Assets, Noncurrent	7	9
Total derivative assets	7	9
Current derivative liabilities	47	47
Derivative Liabilities, Noncurrent	79	82
Total derivative liabilities	126	129
Net derivative assets (liabilities)	-119	-120
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	7	9
Total derivative liabilities	113	115
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	0	0
Total derivative liabilities	13	14
Commodity Option [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, current	655	445
Derivative Assets, Noncurrent	167	96
Total derivative assets	822	541
Current derivative liabilities	681	404
Derivative Liabilities, Noncurrent	151	161
Total derivative liabilities	832	565
Net derivative assets (liabilities)	-10	-24
Commodity Option [Member] | Not Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Total derivative assets	822	541
Total derivative liabilities	$832	$565

Derivative_Instruments_Details2

Derivative Instruments (Details 3) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Summary of Derivative Instruments by Risk Exposure [Abstract]	'		'
Power contracts included in operating revenues	($237)		($74)
Natural gas contracts included in fuel and purchased energy expense	125		45
Interest rate swaps included in interest expense	1		2
Gain (Loss) on Derivative Instruments, Net, Pretax	-111		-27
Gain (Loss) on Sale of Derivatives	-39	[1]	28	[1]
Unrealized gain (loss)	-72	[2]	-55	[2]
Interest Rate Swap [Member]	'		'
Summary of Derivative Instruments by Risk Exposure [Abstract]	'		'
Unrealized gain (loss)	1	[2]	2	[2]
Commodity Option [Member]	'		'
Summary of Derivative Instruments by Risk Exposure [Abstract]	'		'
Gain (Loss) on Sale of Derivatives	-39	[1]	28	[1]
Unrealized gain (loss)	($73)	[2]	($57)	[2]
[1]	Does not include the realized value associated with derivative instruments that settle through physical delivery.
[2]	In addition to changes in market value on derivatives not designated as hedges, changes in unrealized gain (loss) also includes de-designation of interest rate swap cash flow hedges and related reclassification from AOCI into earnings, hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.

Derivative_Instruments_Details3

Derivative Instruments (Details 4) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Gains (Loss) Recognized in OCI (Effective Portion)	$0	[1]	$13	[1]
Gain (Loss) Reclassified from AOCI into Income (EffectivePortion)	-13	[1],[2]	-9	[1],[2]
Interest Rate Swap [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Gains (Loss) Recognized in OCI (Effective Portion)	0	[3]	13	[3]
Gain (Loss) Reclassified from AOCI into Income (EffectivePortion)	($13)	[2],[3],[4]	($9)	[2],[3]
[1]	We recorded an income tax benefit of nil and $1 million for the three months ended March 31, 2014 and 2013, respectively, in AOCI related to our cash flow hedging activities.
[2]	Cumulative cash flow hedge losses attributable to Calpine, net of tax, remaining in AOCI were $148 million at each of March 31, 2014 and December 31, 2013. Cumulative cash flow hedge losses attributable to the noncontrolling interest, net of tax, remaining in AOCI were $11 million at each of March 31, 2014 and December 31, 2013.
[3]	We did not record any gain (loss) on hedge ineffectiveness related to our interest rate swaps designated as cash flow hedges during the three months ended March 31, 2014 and 2013.
[4]	Includes a loss of $5 million that was reclassified from AOCI to interest expense for the three months ended March 31, 2014 where the hedged transactions are no longer expected to occur.

Derivative_Instruments_Textual

Derivative Instruments (Textuals) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013
			Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member]
Derivatives, Fair Value [Line Items]	'	'	'	'	'	'
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$0	$1	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	'	'	148	148	11	11
Derivative Instruments (Textuals) [Abstract]	'	'	'	'	'	'
Maximum length of time hedging using interest rate derivative instruments	'10 years	'	'	'	'	'
Derivative, Net Liability Position, Aggregate Fair Value	58	'	'	'	'	'
Collateral Already Posted, Aggregate Fair Value	7	'	'	'	'	'
Additional Collateral, Aggregate Fair Value	1	'	'	'	'	'
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	5	'	'	'	'	'
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$43	'	'	'	'	'

Derivative_Instruments_Detail_

Derivative Instruments (Detail 5) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments Subject to Master Netting Arrangement [Line Items]	'		'
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net	($129)		($144)
Derivative Fair Value, Amount Not Offset Against Collateral, Net	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral	34		56
Derivative Asset, Fair Value, Gross Asset	829		550
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	-747		-480
Derivative Liability, Fair Value, Gross Liability	-958		-694
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	747		480
Margin/Cash (Received) Posted Subject to Master Netting Arrangement	-26	[1]	62	[1]
Derivative Liability, Fair Value, Amount Offset Against Collateral	-189		-138
Derivative, Fair Value, Amount Offset Against Collateral, Net	-155		-82
Derivative, Collateral, Right to Reclaim Cash	22	[1]	76	[1]
Derivative, Collateral, Obligation to Return Cash	-48	[1]	-14	[1]
Commodity Exchange Traded Futures and Swaps Contracts [Member]	'		'
Derivative Instruments Subject to Master Netting Arrangement [Line Items]	'		'
Derivative Asset, Fair Value, Amount Offset Against Collateral	0		0
Derivative Asset, Fair Value, Gross Asset	717		434
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	-669		-420
Derivative Liability, Fair Value, Gross Liability	-684		-495
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	669		420
Derivative Liability, Fair Value, Amount Offset Against Collateral	0		0
Derivative, Collateral, Right to Reclaim Cash	15	[1]	75	[1]
Derivative, Collateral, Obligation to Return Cash	-48	[1]	-14	[1]
Commodity Forward Contract [Member]	'		'
Derivative Instruments Subject to Master Netting Arrangement [Line Items]	'		'
Derivative Asset, Fair Value, Amount Offset Against Collateral	27		47
Derivative Asset, Fair Value, Gross Asset	105		107
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	-78		-60
Derivative Liability, Fair Value, Gross Liability	-148		-70
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	78		60
Derivative Liability, Fair Value, Amount Offset Against Collateral	-63		-9
Derivative, Collateral, Right to Reclaim Cash	7	[1]	1	[1]
Derivative, Collateral, Obligation to Return Cash	0	[1]	0	[1]
Interest Rate Swap [Member]	'		'
Derivative Instruments Subject to Master Netting Arrangement [Line Items]	'		'
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net	-119		-120
Derivative Asset, Fair Value, Amount Offset Against Collateral	7		9
Derivative Asset, Fair Value, Gross Asset	7		9
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0		0
Derivative Liability, Fair Value, Gross Liability	-126		-129
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	-126		-129
Derivative, Collateral, Right to Reclaim Cash	0	[1]	0	[1]
Derivative, Collateral, Obligation to Return Cash	$0	[1]	$0	[1]
[1]	Negative balances represent margin deposits posted with us by our counterparties related to our derivative activities that are subject to a master netting arrangement. Positive balances reflect margin deposits posted by us with our counterparties related to our derivative activities that are subject to a master netting arrangement. See Note 7 for a further discussion of our collateral.

Use_of_Collateral_Details

Use of Collateral (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Use of Collateral [Abstract]	'		'
Margin deposits	$235	[1]	$261	[1]
Natural gas and power prepayments	29		28
Total margin deposits and natural gas and power prepayments with our counterparties	264	[2]	289	[2]
Letters of credit issued	536		488
First priority liens under power and natural gas agreements	24		31
First priority liens under interest rate swap agreements	128		132
Total letters of credit and first priority liens with our counterparties	688		651
Margin deposits held by us posted by our counterparties	18	[1],[3]	5	[1],[3]
Letters of credit posted with us by our counterparties	2		2
Total margin deposits and letters of credit posted with us by our counterparties	20		7
Use of Collateral (Textuals) [Abstract]	'		'
Margin And Prepayment Amounts Included In Other Assets	15		17
Margin And Prepayment Amounts Included In Margin Deposits And Other Prepaid Expenses	$249		$272
[1]	Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 6 for further discussion of our derivative instruments subject to master netting arrangements.
[2]	At March 31, 2014 and December 31, 2013, $249 million and $272 million, respectively, were included in margin deposits and other prepaid expense and $15 million and $17 million, respectively, were included in other assets on our Consolidated Condensed Balance Sheets.
[3]	Included in other current liabilities on our Consolidated Condensed Balance Sheets.

Income_Taxes_Income_Tax_Expens

Income Taxes (Income Tax Expense (Benefit)) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Contingency [Line Items]	'	'
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	$9,000,000	'
Income tax (expense) benefit	19,000,000	50,000,000
Effective Income Tax Rate, Continuing Operations	53.00%	29.00%
Unrecognized Tax Benefits	66,000,000	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	16,000,000	'
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward	50,000,000	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	13,000,000	'
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	$0	'

Earnings_Loss_per_Share_Detail

Earnings (Loss) per Share (Details)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings (Loss) per Share [Abstract]	'	'
Share-based awards	8,995	10,963

StockBased_Compensation_Schedu

Stock-Based Compensation (Schedule of Non-qualified Stock Option Activity) (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'
Options, Outstanding	13,927,858	14,114,289
Options, Outstanding, Weighted Average Exercise Price	$18.29	$18.25
Options, Outstanding, Weighted Average Remaining Contractual Term	'2 years 9 months 19 days	'3 years 1 month 6 days
Options, Outstanding, Intrinsic Value	$48	$36
Options, Grants in Period, Gross	0	'
Options, Grants in Period, Weighted Average Exercise Price	$0	'
Options, Exercises in Period	184,931	'
Options, Exercises in Period, Weighted Average Exercise Price	$15.56	'
Options, Forfeitures in Period	0	'
Options, Forfeitures in Period, Weighted Average Exercise Price	$0	'
Options, Expirations in Period	1,500	'
Options, Expirations in Period, Weighted Average Exercise Price	$17.39	'
Options, Exercisable	13,012,308	'
Options, Exercisable, Weighted Average Exercise Price	$18.50	'
Options, Exercisable, Weighted Average Remaining Contractual Term	'2 years 6 months 2 days	'
Options, Exercisable, Intrinsic Value	43	'
Options, Vested and Expected to Vest, Outstanding	13,871,693	'
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$18.30	'
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	'2 years 9 months 19 days	'
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$48	'

StockBased_Compensation_Asummp

Stock-Based Compensation (Asummptions used to estimate fair value for options) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	'6 years 6 months	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	1.40%	[2]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	25.60%	[3]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%	[4]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$5.31
[1]	Expected term calculated using the simplified method prescribed by the SEC due to the lack of sufficient historical exercise data on the grant date to provide a reasonable basis to estimate the expected term.
[2]	Zero Coupon U.S. Treasury rate or equivalent based on expected term.
[3]	Volatility calculated using the implied volatility of our exchange traded stock options.
[4]	We have never paid cash dividends on our common stock, and we do not anticipate any cash dividend payments on our common stock in the near future.

StockBased_Compensation_Summar

Stock-Based Compensation (Summary restricted stock and restricted stock unit activity) (Details) (Restricted Stock [Member], USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Restricted Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	4,735,696	4,431,841
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$17.86	$16.45
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,764,446	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$19.11	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	25,977	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$17.03	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	1,434,614	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$15.07	'

StockBased_Compensation_Stock_

Stock-Based Compensation (Stock Based Compensation Textuals) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013		Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	'	1.40%	[1]	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	'	25.60%	[2]	'
Vesting period for graded and cliff vesting options - minimum	'1 year	'		'
Vesting period for graded and cliff vesting options - maximum	'5 years	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Minimum Range	'5 years	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Maximum Range	'10 years	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized for Directors	567,000	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized for Employees	40,533,000	'		'
Percentage of sub-grants representing the total	33.33%	'		'
Vest Term of First Sub Grant	'1 year	'		'
Vest Term of the Second Sub-Grant	'2 years	'		'
Vest Term of the Third Sub-Grant	'3 years	'		'
Grants in Option Grants with Three Year Cliff Vesting	1	'		'
Vesting term of option grants with three year cliff vesting	'3 years	'		'
Allocated Share-based Compensation Expense	$9	$8		'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	1	2		'
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	3	9		'
Allocated Share Based Compensation Expense Liability Classified Share-Based Awards	1	0		'
Stock Options [Member]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'		'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	1	'		'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'10 months 25 days	'		'
Restricted Stock [Member]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	4,735,696	'		4,431,841
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	47	'		'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'1 year 8 months 13 days	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	29	20		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,764,446	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$19.11	'		'
Restricted Stock Units (RSUs) [Member]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'		'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$0	'		'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'1 month 6 days	'		'
Performance Shares [Member]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	895,879	'		449,798
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	461,393	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$22.56	'		'
[1]	Zero Coupon U.S. Treasury rate or equivalent based on expected term.
[2]	Volatility calculated using the implied volatility of our exchange traded stock options.

StockBased_Compensation_Liabil

Stock-Based Compensation Liability Based Stock Compensation (Details) (Performance Shares [Member], USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Performance Shares [Member]	'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$21.92		$21.25
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	461,393		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$22.56		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$0		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	15,312	[1]	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$21.25		'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	895,879		449,798
[1]	(1)In accordance with the applicable performance share unit agreements, performance share units granted to employees who meet the retirement eligibility requirements stipulated in the Equity Plan are fully vested upon the later of the date on which the employee becomes eligible to retire or one-year anniversary of the grant date.

Segment_and_Significant_Custom2

Segment and Significant Customer Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	$1,965		$1,241
Intersegment revenue	0		0
Operating revenues	1,965		1,241
Commodity Margin	645		461
Add: Mark-to-market commodity activity, net and other	-37	[1]	-41	[1]
Plant operating expense	265		227
Depreciation and amortization expense	153		146
Sales, general and other administrative expense	33		33
Other operating expenses	22		18
(Income) loss from unconsolidated investments in power plants	-9		-8
Income from operations	144		4
Interest expense, net of interest income	165		174
Other (income) expense, net	11		5
Loss before income taxes	-32		-175
Lease levelization	-29		-16
Contract amortization	4		4
West [Member]	'		'
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	491		383
Intersegment revenue	2		1
Operating revenues	493		384
Commodity Margin	202		202
Add: Mark-to-market commodity activity, net and other	29	[1]	-37	[1]
Plant operating expense	105		95
Depreciation and amortization expense	60		53
Sales, general and other administrative expense	10		7
Other operating expenses	12		9
(Income) loss from unconsolidated investments in power plants	0		0
Income from operations	44		1
Texas [Member]	'		'
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	647		407
Intersegment revenue	12		7
Operating revenues	659		414
Commodity Margin	121		76
Add: Mark-to-market commodity activity, net and other	-46	[1]	-11	[1]
Plant operating expense	90		65
Depreciation and amortization expense	42		42
Sales, general and other administrative expense	12		14
Other operating expenses	2		1
(Income) loss from unconsolidated investments in power plants	0		0
Income from operations	-71		-57
North [Member]	'		'
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	639		306
Intersegment revenue	15		7
Operating revenues	654		313
Commodity Margin	267		142
Add: Mark-to-market commodity activity, net and other	-17	[1]	7	[1]
Plant operating expense	52		43
Depreciation and amortization expense	33		33
Sales, general and other administrative expense	6		6
Other operating expenses	6		7
(Income) loss from unconsolidated investments in power plants	-9		-8
Income from operations	162		68
Southeast [Member]	'		'
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	188		145
Intersegment revenue	81		33
Operating revenues	269		178
Commodity Margin	55		41
Add: Mark-to-market commodity activity, net and other	6	[1]	7	[1]
Plant operating expense	27		31
Depreciation and amortization expense	18		19
Sales, general and other administrative expense	6		6
Other operating expenses	1		1
(Income) loss from unconsolidated investments in power plants	0		0
Income from operations	9		-9
Intersegment Elimination [Member]	'		'
Revenues from External Customers and Long-Lived Assets [Line Items]	'		'
Revenue from External Customer	0		0
Intersegment revenue	-110		-48
Operating revenues	-110		-48
Commodity Margin	0		0
Add: Mark-to-market commodity activity, net and other	-9	[1]	-7	[1]
Plant operating expense	-9		-7
Depreciation and amortization expense	0		-1
Sales, general and other administrative expense	-1		0
Other operating expenses	1		0
(Income) loss from unconsolidated investments in power plants	0		0
Income from operations	$0		$1
[1]	Includes $(29) million and $(16) million of lease levelization and $4 million and $4 million of amortization expense for the three months ended March 31, 2014 and 2013, respectively.