XML 99 R83.htm IDEA: XBRL DOCUMENT v3.10.0.1

Fair Value of Financial Instruments - Assets and Liabilities Measured and Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	$ 663	$ 692
Commodity contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	1,042	744
Derivative liabilities	977	674
Interest rate contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	39	39
Derivative liabilities		6
Cash and cash equivalents
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	19	47
U.S. government and federal agency obligations
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	46	43
Federal agency mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	100	82
Commercial mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	22	14
Corporate debt securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	96	99
Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	376	402
Foreign government fixed income securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	4	5
Level 1 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Equity securities-nuclear trust fund investments	0
Level 2 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Equity securities-nuclear trust fund investments	0
Level 3 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Equity securities-nuclear trust fund investments	0
Fair Value, Measurements, Recurring
Investment in available-for-sale securities (classified within other non-current assets):
Investments in securities (classified within other current or non-current assets)	39	39
U.S. government and federal agency obligations	1	1
Total assets	1,792	1,523
Total liabilities	977	680
Fair Value, Measurements, Recurring | Commodity contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	1,042	744
Derivative liabilities	977	674
Fair Value, Measurements, Recurring | Interest rate contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	39	39
Derivative liabilities		6
Fair Value, Measurements, Recurring | Cash and cash equivalents
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	19	47
Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	46	43
Fair Value, Measurements, Recurring | Federal agency mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	100	82
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	22	14
Fair Value, Measurements, Recurring | Corporate debt securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	96	99
Fair Value, Measurements, Recurring | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	312	334
Equity securities-nuclear trust fund investments	8	8
Fair Value, Measurements, Recurring | Foreign government fixed income securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	4	5
Fair Value, Measurements, Recurring | Equity securities-nuclear trust fund investments
Investment in available-for-sale securities (classified within other non-current assets):
Equity securities-nuclear trust fund investments	64	68
Fair Value, Measurements, Recurring | Level 1
Investment in available-for-sale securities (classified within other non-current assets):
Investments in securities (classified within other current or non-current assets)	2	3
U.S. government and federal agency obligations	1	1
Total assets	517	616
Total liabilities	224	257
Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	137	191
Derivative liabilities	224	257
Fair Value, Measurements, Recurring | Level 1 | Interest rate contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	0	0
Derivative liabilities		0
Fair Value, Measurements, Recurring | Level 1 | Cash and cash equivalents
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	19	45
Fair Value, Measurements, Recurring | Level 1 | U.S. government and federal agency obligations
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	46	42
Fair Value, Measurements, Recurring | Level 1 | Federal agency mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 1 | Corporate debt securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	312	334
Fair Value, Measurements, Recurring | Level 1 | Foreign government fixed income securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 2
Investment in available-for-sale securities (classified within other non-current assets):
Investments in securities (classified within other current or non-current assets)	18	17
U.S. government and federal agency obligations	0	0
Total assets	1,075	768
Total liabilities	664	364
Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	796	509
Derivative liabilities	664	358
Fair Value, Measurements, Recurring | Level 2 | Interest rate contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	39	39
Derivative liabilities		6
Fair Value, Measurements, Recurring | Level 2 | Cash and cash equivalents
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	2
Fair Value, Measurements, Recurring | Level 2 | U.S. government and federal agency obligations
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	1
Fair Value, Measurements, Recurring | Level 2 | Federal agency mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	100	82
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	22	14
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	96	99
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 2 | Foreign government fixed income securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	4	5
Fair Value, Measurements, Recurring | Level 3
Investment in available-for-sale securities (classified within other non-current assets):
Investments in securities (classified within other current or non-current assets)	19	19
U.S. government and federal agency obligations	0	0
Total assets	128	63
Total liabilities	89	59
Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	109	44
Derivative liabilities	89	59
Fair Value, Measurements, Recurring | Level 3 | Interest rate contracts
Investment in available-for-sale securities (classified within other non-current assets):
Derivative assets	0	0
Derivative liabilities		0
Fair Value, Measurements, Recurring | Level 3 | Cash and cash equivalents
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government and federal agency obligations
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Federal agency mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government fixed income securities
Investment in available-for-sale securities (classified within other non-current assets):
Nuclear trust fund investments	$ 0	$ 0

X

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (available-for-sale), classified as noncurrent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26626-111562

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

Name:	us-gaap_DecommissioningTrustAssetsAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=SL51823488-111719

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=SL51823488-111719

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The fair value as of the balance sheet date of firm holdings in debt obligations issued by the US government including short-term Treasury bills, medium-term Treasury notes, and long-term Treasury bonds, as well as debt issued by agencies. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969

+ Details

Name:	us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value of financial and nonfinancial obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nrg_EquitySecuritiesNuclearTrustFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: