v2.4.0.6

Commitments and Contingencies (Schedule of Environmental Loss Contingencies)(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended							3 Months Ended									3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Minimum [Member]	Mar. 31, 2013 Maximum [Member]	Mar. 31, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member] Minimum [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member] Maximum [Member]	Mar. 31, 2013 Duke Energy Ohio [Member]	Mar. 31, 2012 Duke Energy Ohio [Member]	Mar. 31, 2013 Duke Energy Ohio [Member] Minimum [Member]	Mar. 31, 2013 Duke Energy Ohio [Member] Maximum [Member]	Mar. 31, 2013 Duke Energy Indiana [Member]	Mar. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2011 Duke Energy Indiana [Member]	Mar. 31, 2013 Duke Energy Indiana [Member] Minimum [Member]	Mar. 31, 2013 Duke Energy Indiana [Member] Maximum [Member]	Mar. 31, 2013 Progress Energy [Member]	Mar. 31, 2012 Progress Energy [Member]	Mar. 31, 2013 Progress Energy [Member] Minimum [Member]	Mar. 31, 2013 Progress Energy [Member] Maximum [Member]	Mar. 31, 2013 Duke Energy Progress [Member]	Mar. 31, 2012 Duke Energy Progress [Member]	Mar. 31, 2013 Duke Energy Progress [Member] Minimum [Member]	Mar. 31, 2013 Duke Energy Progress [Member] Maximum [Member]	Mar. 31, 2013 Duke Energy Florida [Member]	Mar. 31, 2012 Duke Energy Florida [Member]	Mar. 31, 2013 Duke Energy Florida [Member] Minimum [Member]	Mar. 31, 2013 Duke Energy Florida [Member] Maximum [Member]
Disclosure Environmental Matters Details [Line Items]
Beginning balance	$ 75	$ 61			$ 12	$ 12	$ 12			$ 15	$ 28			$ 8	$ 9	$ 9			$ 33	$ 23			$ 14	$ 11			$ 19	$ 12
Amounts accrued for environmental loss contingencies	2	4			1						2								1	5				(1)			1	6
Expenditures for environmental loss contingencies	(6)	(7)								(2)	(5)			(1)					(2)	(4)			(1)	(1)			(1)	(3)
Ending balance	71	58			13	12	12			13	25			7	9	9			32	24			13	9			19	15
Estimated cost of complying with EPA Mercury and Air Toxics Standards			$ 650	$ 800				$ 65	$ 85			$ 40	$ 85				$ 540	$ 600			$ 7	$ 30			$ 5	$ 10			$ 2	$ 20

X

- Definition

The increase (decrease) in the accrual for environmental loss contingencies. These changes include remediation expense for provision of new losses and revisions in estimates of existing losses.

+ References

No definition available.

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- Definition

Estimated cost of complying with recently issued and proposed EPA Mercury and Air Toxics Standards

+ References

No definition available.

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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 25

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 96-1

-Paragraph 161

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

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- Definition

The aggregate amount disbursed during the reporting period to settle environmental loss contingencies.

+ 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)

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