Asset Retirement Obligations (NDTF Information)(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	$ 5,182	$ 4,769
Duke Energy Carolinas [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	2,678	2,477
Duke Energy Carolinas [Member] \| 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning contribution requirement	21
Decommissioning cost study estimate	3,420
Duke Energy Progress [Member] \| 2014 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning contribution requirement	14
Decommissioning cost study estimate	3,062
Duke Energy Florida [Member] \| 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning cost study estimate	$ 1,083

Contribution and expense amounts for decommissioning costs required by each entity's state regulatory commission.

No definition available.

Name:	duk_ContributionAndExpenseAmountsForDecommissioning
Namespace Prefix:	duk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount of an asset that is legally restricted for purposes of settling an asset retirement obligation.

+ References

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

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

- Definition

Amount of a decommissioning liability associated with a legal obligation that a firm incurs when it constructs or operates an asset that must eventually be withdrawn from active service. This may include operating assets such as nuclear power plants or shipping vessels.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q2)

-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

+ Details

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

- Details

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

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyCarolinasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyFloridaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyProgressMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: