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v3.20.2

Changes in Capital Structure - Changes in NRG's common stock issued and outstanding (Details) - shares | 1 Months Ended | 9 Months Ended
--- | --- | ---
Nov. 05, 2020 | Sep. 30, 2020
Schedule of Stock by Class, Equity [Roll Forward] |  |
Balance as of beginning of period (in shares) | 423,041,349 | 421,890,790
Treasury shares, balance as of beginning of period (in shares) | (178,893,929) | (172,894,601)
Outstanding, as of beginning of period (in shares) | 244,147,420 | 248,996,189
Shares issued under LTIPs (in shares) |  | 1,150,559
Stock issued under ESPP (in shares) |  | 63,455
Shares repurchased (in shares) |  | (6,062,783)
Balance as of end of period (in shares) |  | 423,041,349
Treasury shares, balance as of end of the period (in shares) |  | (178,893,929)
Outstanding, as of end of period (in shares) |  | 244,147,420
Subsequent Event |  |
Schedule of Stock by Class, Equity [Roll Forward] |  |
Shares issued under LTIPs (in shares) | 5,400 |
Stock issued under ESPP (in shares) | 68,014 |
Outstanding, as of end of period (in shares) | 244,220,834 |
Common Stock |  |
Schedule of Stock by Class, Equity [Roll Forward] |  |
Balance as of beginning of period (in shares) | 423,041,349 | 421,890,790
Shares issued under LTIPs (in shares) |  | 1,150,559
Stock issued under ESPP (in shares) |  | 0
Shares repurchased (in shares) |  | 0
Balance as of end of period (in shares) |  | 423,041,349
Common Stock | Subsequent Event |  |
Schedule of Stock by Class, Equity [Roll Forward] |  |
Shares issued under LTIPs (in shares) | 5,400 |
Stock issued under ESPP (in shares) | 0 |
Balance as of end of period (in shares) | 423,046,749 |
Treasury |  |
Schedule of Stock by Class, Equity [Roll Forward] |  |
Treasury shares, balance as of beginning of period (in shares) | (178,893,929) | (172,894,601)
Shares issued under LTIPs (in shares) |  | 0
Stock issued under ESPP (in shares) |  | 63,455
Shares repurchased (in shares) |  | (6,062,783)
Treasury shares, balance as of end of the period (in shares) |  | (178,893,929)
Treasury | Subsequent Event |  |
Schedule of Stock by Class, Equity [Roll Forward] |  |
Shares issued under LTIPs (in shares) | 0 |
Stock issued under ESPP (in shares) | 68,014 |
Treasury shares, balance as of end of the period (in shares) | (178,825,915) |

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- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Number of shares issued during the period as a result of an employee stock purchase plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Number, after forfeiture, of shares or units issued under share-based payment arrangement. Excludes shares or units issued under employee stock ownership plan (ESOP). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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