Commitments and Contingencies (PurchPower)(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Duke Energy Progress [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Duke Energy Progress [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
2015	59
2016	60
2017	61
2018	62
2019	63
Thereafter	93
Total	398
Duke Energy Progress [Member] \| Minimum [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2019
Duke Energy Progress [Member] \| Maximum [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2022
Duke Energy Florida [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Duke Energy Florida [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
2015	244
2016	273
2017	291
2018	306
2019	322
Thereafter	1,907
Total	3,343
Duke Energy Florida [Member] \| Minimum [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2023
Duke Energy Florida [Member] \| Maximum [Member] \| Public Utilities Purchased Power [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2043

No authoritative reference available.

No definition available.

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- Definition

Share of plant output being purchased under a long-term contract to purchase electricity from a production plant constructed and financed by a public utility district, cooperative, or other organization.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 10.D)

-URI http://asc.fasb.org/extlink&oid=6499423&loc=d3e659339-123030

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 10

-Section D

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

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Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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