Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease assets, cost basis	$ 155,580	$ 147,654
Piedmont
Lessee, Lease, Description [Line Items]
Operating lease assets, cost basis	9,134	8,446
Construction and transportation of natural gas pipelines \| Piedmont
Lessee, Lease, Description [Line Items]
Net investment in lease, current	2	4
Renewable energy projects
Lessee, Lease, Description [Line Items]
Contingent lease payments	275	264	$ 268
Operating lease assets, cost basis	3,335	3,349
Operating lease assets, accumulated depreciation	848	721
Duke Energy Carolinas \| Construction and transportation of natural gas pipelines \| Piedmont
Lessee, Lease, Description [Line Items]
Net investment in lease, noncurrent	$ 205	$ 70

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- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.14)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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+ References

No definition available.

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- Definition

Amount of net investment in sales-type and direct financing lease, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121561866&loc=SL77919306-209978

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
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Amount of net investment in sales-type and direct financing lease, classified as noncurrent.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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