Severance (Rollforward) (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 19
Provision/adjustments	200
Cash reductions	(14)
Balance, end of period	205
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	5
Provision/adjustments	98
Cash reductions	(3)
Balance, end of period	100
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	2
Provision/adjustments	50
Cash reductions	(1)
Balance, end of period	51
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	1
Provision/adjustments	40
Balance, end of period	41
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Provision/adjustments	10
Cash reductions	(1)
Balance, end of period	9
Duke Energy Ohio [Member]
Restructuring Reserve [Roll Forward]
Provision/adjustments	2
Balance, end of period	2
Duke Energy Indiana [Member]
Restructuring Reserve [Roll Forward]
Provision/adjustments	2
Balance, end of period	2
Piedmont Natural Gas [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	5
Cash reductions	$ (5)

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3367-108585

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

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Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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