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Nature of Business and Basis of Presentation - General (Details) counterparty in Millions | 9 Months Ended
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Sep. 30, 2021 counterparty MW
Business Acquisition [Line Items] |
Generation capacity (in MW) | 23,000
East |
Business Acquisition [Line Items] |
Generation capacity (in MW) | 1,600
Disposal Group, Held-for-sale, Not Discontinued Operations |
Business Acquisition [Line Items] |
Generation capacity (in MW) | 4,850
Home |
Business Acquisition [Line Items] |
Customers | counterparty | 6

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- Definition Number of customers + References No definition available. + Details
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Balance Type: | na
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X
- Definition The generation capacity of the entity's power generation facilities as of the balance sheet date, expressed in megawatts. + References No definition available. + Details
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Namespace Prefix: | nrg_
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Balance Type: | na
Period Type: | instant

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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X
- Details
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Namespace Prefix: |
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Period Type: |

X
- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |