Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Maximum years of participation	35 years
Matching contribution percentage	100.00%
Eligible pay percentage	6.00%
Additional savings plan account contribution percentage for employees not participating in defined pension plans	4.00%
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	132
Duke Energy Carolinas [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	42
Progress Energy [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	42
Duke Energy Progress [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	21
Duke Energy Florida [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	21
Duke Energy Ohio [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	1
Duke Energy Indiana [Member] \| Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	9

Defined Benefit Plan, Maximum years of participation

No definition available.

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- Definition

Percentage of eligible pay per period contributed to an employee's 401(k) account in lieu of participation in Duke Energy's defined pension plans.

+ References

No definition available.

+ Details

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ 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 (b)(3)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

+ Details

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- Details

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- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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