v3.3.0.814

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014
Qualified Pension Plans [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | $ 40 | $ 34 | $ 119 | $ 102
Interest cost on projected benefit obligation | 81 | 86 | 244 | 258
Expected return on plan assets | (129) | (128) | (387) | (383)
Amortization of actuarial loss (gain) | 44 | 37 | 131 | 111
Amortization of prior service cost (credit) | (4) | (4) | (11) | (11)
Other | 2 | 3 | 6 | 6
Net periodic costs | 34 | 28 | 102 | 83
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 13 | 10 | 38 | 31
Interest cost on projected benefit obligation | 21 | 22 | 62 | 64
Expected return on plan assets | (35) | (33) | (104) | (99)
Amortization of actuarial loss (gain) | 10 | 8 | 30 | 26
Amortization of prior service cost (credit) | (2) | (2) | (6) | (6)
Other | 1 | 1 | 2 | 2
Net periodic costs | 8 | 6 | 22 | 18
Qualified Pension Plans [Member] | Progress Energy [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 11 | 10 | 33 | 30
Interest cost on projected benefit obligation | 26 | 28 | 78 | 84
Expected return on plan assets | (43) | (44) | (127) | (130)
Amortization of actuarial loss (gain) | 17 | 17 | 51 | 51
Amortization of prior service cost (credit) | (1) |  | (3) | (2)
Other | 1 | 1 | 2 | 2
Net periodic costs | 11 | 12 | 34 | 35
Qualified Pension Plans [Member] | Duke Energy Progress [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 6 | 6 | 18 | 16
Interest cost on projected benefit obligation | 12 | 13 | 36 | 40
Expected return on plan assets | (20) | (21) | (61) | (64)
Amortization of actuarial loss (gain) | 8 | 8 | 25 | 24
Amortization of prior service cost (credit) |  |  | (1) | (1)
Other |  |  | 1 | 1
Net periodic costs | 6 | 6 | 18 | 16
Qualified Pension Plans [Member] | Duke Energy Florida [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 5 | 5 | 15 | 15
Interest cost on projected benefit obligation | 14 | 14 | 41 | 43
Expected return on plan assets | (22) | (21) | (66) | (64)
Amortization of actuarial loss (gain) | 8 | 8 | 24 | 24
Amortization of prior service cost (credit) |  |  | (1) | (1)
Other |  |  | 1 | 1
Net periodic costs | 5 | 6 | 14 | 18
Qualified Pension Plans [Member] | Duke Energy Ohio [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 1 | 1 | 3 | 3
Interest cost on projected benefit obligation | 5 | 5 | 14 | 15
Expected return on plan assets | (7) | (7) | (20) | (20)
Amortization of actuarial loss (gain) | 3 | 1 | 8 | 3
Net periodic costs | 2 |  | 5 | 1
Qualified Pension Plans [Member] | Duke Energy Indiana [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 3 | 3 | 8 | 7
Interest cost on projected benefit obligation | 7 | 7 | 21 | 22
Expected return on plan assets | (10) | (10) | (31) | (30)
Amortization of actuarial loss (gain) | 3 | 3 | 10 | 9
Net periodic costs | 3 | 3 | 8 | 8
Other Pension Plan [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 1 | 1 | 2 | 2
Interest cost on projected benefit obligation | 3 | 3 | 10 | 10
Amortization of actuarial loss (gain) | 2 | 1 | 5 | 2
Net periodic costs | 6 | 5 | 17 | 14
Other Pension Plan [Member] | Duke Energy Carolinas [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Interest cost on projected benefit obligation |  | 1 | 1 | 1
Net periodic costs |  | 1 | 1 | 1
Other Pension Plan [Member] | Progress Energy [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  |  | 1 | 1
Interest cost on projected benefit obligation | 1 | 2 | 3 | 4
Amortization of actuarial loss (gain) | 1 |  | 2 | 1
Amortization of prior service cost (credit) |  | (1) |  | (1)
Net periodic costs | 2 | 1 | 6 | 5
Other Pension Plan [Member] | Duke Energy Progress [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  | 1 |  | 1
Interest cost on projected benefit obligation |  |  | 1 | 1
Net periodic costs |  | 1 | 1 | 2
Other Pension Plan [Member] | Duke Energy Florida [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Interest cost on projected benefit obligation | 1 |  | 2 | 1
Amortization of actuarial loss (gain) |  |  | 1 |
Net periodic costs | 1 |  | 3 | 1
Other Post-Retirement Benefit Plans [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost | 1 | 2 | 4 | 7
Interest cost on projected benefit obligation | 9 | 13 | 27 | 38
Expected return on plan assets | (3) | (3) | (9) | (9)
Amortization of actuarial loss (gain) | 6 | 9 | 19 | 29
Amortization of prior service cost (credit) | (35) | (31) | (105) | (94)
Net periodic costs | (22) | (10) | (64) | (29)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  |  | 1 | 1
Interest cost on projected benefit obligation | 2 | 3 | 6 | 9
Expected return on plan assets | (2) | (2) | (6) | (6)
Amortization of actuarial loss (gain) |  | 1 | (1) | 2
Amortization of prior service cost (credit) | (4) | (3) | (11) | (8)
Net periodic costs | (4) | (1) | (11) | (2)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  | 1 | 1 | 3
Interest cost on projected benefit obligation | 4 | 6 | 11 | 17
Amortization of actuarial loss (gain) | 7 | 10 | 21 | 31
Amortization of prior service cost (credit) | (26) | (24) | (77) | (71)
Net periodic costs | (15) | (7) | (44) | (20)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  |  |  | 1
Interest cost on projected benefit obligation | 2 | 3 | 6 | 8
Amortization of actuarial loss (gain) | 5 | 8 | 14 | 23
Amortization of prior service cost (credit) | (17) | (19) | (50) | (55)
Net periodic costs | (10) | (8) | (30) | (23)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Service cost |  |  |  | 2
Interest cost on projected benefit obligation | 2 | 3 | 5 | 9
Amortization of actuarial loss (gain) | 3 | 3 | 8 | 8
Amortization of prior service cost (credit) | (9) | (5) | (25) | (16)
Net periodic costs | (4) | 1 | (12) | 3
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Interest cost on projected benefit obligation |  |  | 1 | 1
Amortization of actuarial loss (gain) |  |  |  | (1)
Net periodic costs |  |  | 1 |
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member] |  |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] |  |  |  |
Interest cost on projected benefit obligation | 1 | 1 | 3 | 4
Expected return on plan assets |  |  |  | (1)
Amortization of actuarial loss (gain) |  |  | (1) |
Net periodic costs | $ 1 | $ 1 | $ 2 | $ 3

X
- Definition The amount of gains or losses recognized in net periodic benefit cost. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(4) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Prior Service Cost -URI http://asc.fasb.org/extlink&oid=49177896 + Details
Name: | us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Expected Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512171 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(2) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanInterestCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Amount of other defined benefit plan costs. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanOtherCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Service Cost (Component of Net Periodic Pension Cost) -URI http://asc.fasb.org/extlink&oid=6525008 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanServiceCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
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_ProgressEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyFloridaMember
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: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |