XML 122 R80.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Fair value measurement, transfers between activity levels | $ 0 | $ 0 | $ 0 | $ 0
Derivatives (net) |  |  |  |
Balance at beginning of period | (97,000,000) | (91,000,000) | (114,000,000) | (166,000,000)
Purchases, sales, issuances and settlements: |  |  |  |
Purchases |  |  | 56,000,000 | 55,000,000
Settlements | (14,000,000) | (12,000,000) | (43,000,000) | (30,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet | (5,000,000) | 10,000,000 | (15,000,000) | 48,000,000
Balance at end of period | (116,000,000) | (93,000,000) | (116,000,000) | (93,000,000)
Investments and Derivatives, Net |  |  |  |
Balance at beginning of period | (97,000,000) | (91,000,000) | (114,000,000) | (161,000,000)
Total pretax realized or unrealized gains included in comprehensive income |  |  |  | 1,000,000
Purchases, sales, issuances and settlements: |  |  |  |
Purchases |  |  | 56,000,000 | 55,000,000
Sales |  |  |  | (6,000,000)
Settlements | (14,000,000) | (12,000,000) | (43,000,000) | (30,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet | (5,000,000) | 10,000,000 | (15,000,000) | 48,000,000
Balance at end of period | (116,000,000) | (93,000,000) | (116,000,000) | (93,000,000)
Investments [Member] |  |  |  |
Investments |  |  |  |
Balance at beginning of period |  | 0 |  | 5,000,000
Total pretax realized or unrealized gains included in comprehensive income |  |  |  | 1,000,000
Purchases, sales, issuances and settlements: |  |  |  |
Sales |  |  |  | (6,000,000)
Duke Energy Carolinas [Member] | Investments [Member] |  |  |  |
Investments |  |  |  |
Balance at beginning of period |  |  |  | 3,000,000
Total pretax realized or unrealized gains included in comprehensive income |  |  |  | 1,000,000
Purchases, sales, issuances and settlements: |  |  |  |
Sales |  |  |  | (4,000,000)
Duke Energy Ohio [Member] |  |  |  |
Derivatives (net) |  |  |  |
Balance at beginning of period | 9,000,000 | 3,000,000 | 1,000,000 | 5,000,000
Purchases, sales, issuances and settlements: |  |  |  |
Purchases | 0 |  | 7,000,000 | 3,000,000
Settlements | (1,000,000) | (1,000,000) | (2,000,000) | (3,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet |  |  | 2,000,000 | (3,000,000)
Balance at end of period | 8,000,000 | 2,000,000 | 8,000,000 | 2,000,000
Duke Energy Indiana [Member] |  |  |  |
Derivatives (net) |  |  |  |
Balance at beginning of period | 44,000,000 | 51,000,000 | 27,000,000 | 16,000,000
Purchases, sales, issuances and settlements: |  |  |  |
Purchases | 0 | 0 | 49,000,000 | 52,000,000
Settlements | (13,000,000) | (11,000,000) | (41,000,000) | (27,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet | (2,000,000) | (12,000,000) | (6,000,000) | (13,000,000)
Balance at end of period | 29,000,000 | 28,000,000 | 29,000,000 | 28,000,000
Piedmont Natural Gas [Member] |  |  |  |
Derivatives (net) |  |  |  |
Balance at beginning of period | (150,000,000) | (145,000,000) | (142,000,000) | (187,000,000)
Purchases, sales, issuances and settlements: |  |  |  |
Total gains (losses) and settlements | (3,000,000) | 22,000,000 | (11,000,000) | 64,000,000
Balance at end of period | $ (153,000,000) | $ (123,000,000) | $ (153,000,000) | $ (123,000,000)

X
- Definition Fair Value, Instruments Measured On Recurring Basis, Unobservable Inputs Reconciliation, Purchases, Sales, Issues, Settlements [Abstract] + References No definition available. + Details
Name: | duk_FairValueInstrumentsMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlementsAbstract
Namespace Prefix: | duk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Transfers into and out of fair value hierarchy levels for assets or liabilities measured at fair value. + References No definition available. + Details
Name: | duk_FairValueMeasurementTransfersBetweenActivityLevels
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as asset (liability) after deduction of liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References No definition available. + Details
Name: | duk_FairValueMeasurementUnobservableInputsReconciliationNet
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset (liability) measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would be using. + References No definition available. + Details
Name: | duk_FairValueMeasurementUnobservableInputsReconciliationNetGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This element represents the total amount included on the consolidated balance sheet as regulatory assets and liabilities [net] measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. + References No definition available. + Details
Name: | duk_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisDeferredGainsOrLossesAsRegulatoryAssetsAndLiabilitiesNet
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Total amount, including deferred gains or losses, recorded as regulatory assets and liabilities [net] measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. + References No definition available. + Details
Name: | duk_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsDeferredGainsOrLossesAsRegulatoryAssetOrLiability
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of settlements of financial instrument classified as an asset (liability) after deduction of liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References No definition available. + Details
Name: | duk_FairValueNetFinancialAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of sales of financial instrument classified as an asset (liability) after deduction of liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References No definition available. + Details
Name: | duk_FairValueNetFinancialInstrumentMeasureOnRecurringBasisUnobservableInputsReconciliationSales
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of purchases of financial instrument classified as an asset (liability) measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References No definition available. + Details
Name: | duk_FairValueNetFinancialInstrumentUnobservableInputsReconciliationPurchases
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investments and Derivatives, Net [Abstract] + References No definition available. + Details
Name: | duk_InvestmentsandDerivativesNetAbstract
Namespace Prefix: | duk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + 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 (c)(1a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlementsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + 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 (c)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + 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 (c) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlementsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_InvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyCarolinasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyOhioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyIndianaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_PiedmontNaturalGasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |