Asset Retirement Obligations (NDTF Information)(Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
NDTF Information [Abstract]
Decommissioning contribution requirement	$ 14
Decommissioning cost study estimate	8,130
Legally restricted NDTF investments, fair value	4,670	$ 5,182
Duke Energy Carolinas [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	2,686	2,678
Duke Energy Carolinas [Member] \| 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning cost study estimate	3,420
Duke Energy Progress [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	1,984	1,701
Duke Energy Progress [Member] \| 2014 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning contribution requirement	14
Decommissioning cost study estimate	3,550
Duke Energy Florida [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value		$ 803
Duke Energy Florida [Member] \| 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning cost study estimate	$ 1,160

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

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- 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

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- 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associated with a legal obligation that a firm incurs when it constructs or operates an asset that must eventually be withdrawn from active service.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

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- References

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