Goodwill (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill balance	$ 19,425,000,000	$ 19,425,000,000
Accumulated impairment charges	(29,000,000)	(29,000,000)
Goodwill, adjusted for accumulated impairment charges	19,396,000,000	19,396,000,000
Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	17,379,000,000	17,379,000,000
Goodwill, adjusted for accumulated impairment charges	17,379,000,000	17,379,000,000
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	1,924,000,000	1,924,000,000
Goodwill, adjusted for accumulated impairment charges	1,924,000,000	1,924,000,000
Commercial Renewables [Member]
Goodwill [Line Items]
Goodwill balance	122,000,000	122,000,000
Accumulated impairment charges	(29,000,000)	(29,000,000)
Goodwill, adjusted for accumulated impairment charges	93,000,000	93,000,000
Duke Energy Ohio [Member]
Goodwill [Line Items]
Accumulated impairment charges	(216,000,000)	(216,000,000)
Goodwill, adjusted for accumulated impairment charges	920,000,000	920,000,000
Duke Energy Ohio [Member] \| Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill, adjusted for accumulated impairment charges	596,000,000	596,000,000
Duke Energy Ohio [Member] \| Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill, adjusted for accumulated impairment charges	324,000,000	324,000,000
Progress Energy [Member]
Goodwill [Line Items]
Accumulated impairment charges	0	0
Goodwill, adjusted for accumulated impairment charges	3,655,000,000	3,655,000,000
Piedmont Natural Gas [Member]
Goodwill [Line Items]
Accumulated impairment charges	0	0
Goodwill, adjusted for accumulated impairment charges	$ 49,000,000	$ 49,000,000

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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