Asset Retirement Obligations (NDTF Information) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
NDTF Information [Abstract]
Annual funding requirement	$ 24
Decommissioning costs	8,737
Legally restricted NDTF investments, fair value	5,579	$ 5,864
Duke Energy Carolinas [Member]
NDTF Information [Abstract]
Decommissioning costs	4,291
Legally restricted NDTF investments, fair value	3,133	3,321
Progress Energy [Member]
NDTF Information [Abstract]
Annual funding requirement	24
Decommissioning costs	4,446
Legally restricted NDTF investments, fair value	2,446	2,543
Duke Energy Progress [Member]
NDTF Information [Abstract]
Annual funding requirement	24
Decommissioning costs	3,550
Legally restricted NDTF investments, fair value	2,446	$ 2,543
Duke Energy Florida [Member]
NDTF Information [Abstract]
Decommissioning costs	$ 896

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://fasb.org/us-gaap/role/ref/legacyRef
-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associated with a legal obligation that a firm incurs when it constructs or operates an asset that must eventually be withdrawn from active service.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://fasb.org/us-gaap/role/ref/legacyRef
-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

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- References

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