Commitments and contingencies [Line Items]

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- Definition

EPA Rule Addressing Greenhouse Gas Emissions From Existing Electricity Generation Plants, State-Specific Emission Rate Goals, Percent Reduction From 2012 Levels To 2030 Levels

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No definition available.

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- Definition

The value (monetary amount) per day of the award the plaintiff seeks in the legal matter.

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- Definition

Percentage change between proposed and final federal rules governing generation asset annual nitrogen oxides emissions budgets.

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- Definition

Percentage change between proposed and final federal rules governing generation asset seasonal nitrogen oxides emissions budgets.

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- Definition

Percentage change between proposed and final federal rules governing generation asset sulfur dioxide emissions budgets.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Commitments And Contingencies (Narrative) (Details) - USD ($)	1 Months Ended		9 Months Ended
	Aug. 31, 2015	Feb. 29, 2012	Sep. 30, 2015
Commitments and Contingencies [Line Items]
EPA Rule Addressing Greenhouse Gas Emissions From Existing Electricity Generation Plants, State-Specific Emission Rate Goals, Percent Reduction From 2012 Levels To 2030 Levels	30.00%
CSAPR [Member]
Commitments and Contingencies [Line Items]
Emissions budget generation assets lower sulfur dioxide requirements (as a percent)		6.00%
Emissions budget generation assets higher annual nitrogen oxides requirements (as a percent)		3.00%
Emissions budget generation assets higher seasonal nitrogen oxides requirements (as a percent)		2.00%
EPA Versus Luminant and Big Brown Power Company (Big Brown and Martin Lake Generation Facilities) [Member] \| Pending Litigation [Member] \| Minimum [Member]
Commitments and Contingencies [Line Items]
Loss Contingency Damages Sought Value Per Day			$ 32,500
EPA Versus Luminant and Big Brown Power Company (Big Brown and Martin Lake Generation Facilities) [Member] \| Pending Litigation [Member] \| Maximum [Member]
Commitments and Contingencies [Line Items]
Loss Contingency Damages Sought Value Per Day			37,500
Texas Competitive Electric Holdings Company LLC \| Financial Standby Letter of Credit [Member]
Commitments and Contingencies [Line Items]
Letters of Credit			364,000,000
Texas Competitive Electric Holdings Company LLC \| Financial Standby Letter of Credit [Member] \| Support risk management and trading margin requirements, including over-the-counter hedging transactions and collateral postings with ERCOT [Member]
Commitments and Contingencies [Line Items]
Letters of Credit			203,000,000
Texas Competitive Electric Holdings Company LLC \| Financial Standby Letter of Credit [Member] \| Support Executory Contracts And Insurance Agreements [Member]
Commitments and Contingencies [Line Items]
Letters of Credit			74,000,000
Texas Competitive Electric Holdings Company LLC \| Financial Standby Letter of Credit [Member] \| Support Retail Electric Provider's financial requirements with the PUCT [Member]
Commitments and Contingencies [Line Items]
Letters of Credit			55,000,000
Texas Competitive Electric Holdings Company LLC \| Financial Standby Letter of Credit [Member] \| Miscellaneous credit support requirements [Member]
Commitments and Contingencies [Line Items]
Letters of Credit			$ 32,000,000