XML 143 R125.htm IDEA: XBRL DOCUMENT
v3.20.4

Capital Structure - Summary of Changes in Shares Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) | 6,062,783 | 36,301,882 | 35,234,664
Shares repurchased under May 24, 2018 Accelerated Repurchase Agreement |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) |  |  | 10,829,903
Amounts paid for shares and share equivalents purchased (in millions) |  |  | $ 354
Shares repurchased under September 5, 2018 Accelerated Repurchase Agreement |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) |  |  | 13,307,130
Amounts paid for shares and share equivalents purchased (in millions) |  |  | $ 500
Other repurchases |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) | 6,062,783 | 26,863,211 | 11,097,631
Amounts paid for shares and share equivalents purchased (in millions) | $ 197 | $ 1,008 | $ 396
Repurchases under February 28, 2019 Accelerated Share Repurchase Agreement |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) |  | 9,438,671 |
Amounts paid for shares and share equivalents purchased (in millions) |  | $ 400 |
Equivalent shares purchased in lieu of tax withholding on equity compensation issuances |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) | 711,248 | 936,928 |
Average price paid per share (in shares) | $ 38.23 | $ 38.78 |
Amounts paid for shares and share equivalents purchased (in millions) | $ 27 | $ 36 |
Capital Allocation Plan |  |  |
Schedule of Capitalization, Equity [Line Items] |  |  |
Total number of shares purchased (in shares) | 6,774,031 | 37,238,810 | 35,234,664
Average price paid per share (in shares) | $ 33.05 | $ 38.79 | $ 35.48
Amounts paid for shares and share equivalents purchased (in millions) | $ 224 | $ 1,444 | $ 1,250

X
- 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
Name: | us-gaap_ScheduleOfCapitalizationEquityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_StockRepurchasedDuringPeriodShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate 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 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 2: 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 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(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockRepurchasedDuringPeriodValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
Name: | us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_CapitalAllocationPlanAcceleratedRepurchaseAgreementMay2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_CapitalAllocationPlanAcceleratedRepurchaseProgramSeptember2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_CapitalAllocationPlanOpenMarketRepurchasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_CapitalAllocationPlanAcceleratedRepurchaseAgreementFebruaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_EquivalentSharesInLieuOfTaxWithholdingOnEquityCompensationIssuancesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | nrg_CapitalAllocationPlanAxis=nrg_CapitalAllocationPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |