Employee Benefit Plans (Employee Savings Plans)(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Savings Plans [Abstract]
Matching contribution percentage	100.00%
Eligible pay percentage	6.00%
Additional contribution percentage for employees not participating in defined pension plans	4.00%
Pretax employer matching contributions	$ 143	$ 134	$ 107
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	47	45	37
Progress Energy [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	43	45	45
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	30	25	24
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	14	14	15
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	3	3	4
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	$ 7	$ 7	$ 6

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.

No definition available.

+ Details

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Namespace Prefix:	duk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

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- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyOhioMember
Namespace Prefix:
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- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyProgressMember
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- Details

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