v2.4.0.8

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified									9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended		12 Months Ended				9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended										12 Months Ended																						9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended											9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2014 Commodity Natural Gas Hedges [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Natural Gas Hedges [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Natural Gas Hedges [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Natural Gas Hedges [Member] Minimum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Natural Gas Hedges [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Natural Gas Hedges [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 FERC Mitigation Power Sale Agreements [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 FERC Mitigation Power Sale Agreements [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 FERC Mitigation Power Sale Agreements [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Financial Transmission Rights [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Financial Transmission Rights [Member] RTO Auction Pricing [Member]	Sep. 30, 2014 Financial Transmission Rights [Member] Minimum [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Financial Transmission Rights [Member] Minimum [Member] RTO Auction Pricing [Member]	Sep. 30, 2014 Financial Transmission Rights [Member] Maximum [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Financial Transmission Rights [Member] Maximum [Member] RTO Auction Pricing [Member]	Sep. 30, 2014 Commodity Power Contracts [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Power Contracts [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Power Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Power Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Power Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Power Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Capacity Option Contracts [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Capacity Option Contracts [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Capacity Option Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Capacity Option Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Commodity Capacity Option Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Commodity Capacity Option Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Derivative Financial Instruments Liabilities Reserves [Member]	Dec. 31, 2013 Derivative Financial Instruments Liabilities Reserves [Member]	Sep. 30, 2014 Duke Energy Carolinas [Member]	Jun. 30, 2014 Duke Energy Carolinas [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member]	Jun. 30, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member] FERC Mitigation Power Sale Agreements [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member] FERC Mitigation Power Sale Agreements [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member] FERC Mitigation Power Sale Agreements [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Progress Energy [Member]	Jun. 30, 2014 Progress Energy [Member]	Dec. 31, 2013 Progress Energy [Member]	Sep. 30, 2013 Progress Energy [Member]	Jun. 30, 2013 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Sep. 30, 2014 Duke Energy Progress [Member]	Jun. 30, 2014 Duke Energy Progress [Member]	Dec. 31, 2013 Duke Energy Progress [Member]	Sep. 30, 2013 Duke Energy Progress [Member]	Jun. 30, 2013 Duke Energy Progress [Member]	Dec. 31, 2012 Duke Energy Progress [Member]	Sep. 30, 2014 Duke Energy Ohio [Member]	Jun. 30, 2014 Duke Energy Ohio [Member]	Dec. 31, 2013 Duke Energy Ohio [Member]	Sep. 30, 2013 Duke Energy Ohio [Member]	Jun. 30, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Minimum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Natural Gas Hedges [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Minimum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Commodity Power Contracts [Member] Maximum [Member] Discounted Cash Flow [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] Derivative Financial Instruments Liabilities Reserves [Member]	Dec. 31, 2013 Duke Energy Ohio [Member] Derivative Financial Instruments Liabilities Reserves [Member]	Sep. 30, 2014 Duke Energy Indiana [Member]	Jun. 30, 2014 Duke Energy Indiana [Member]	Dec. 31, 2013 Duke Energy Indiana [Member]	Sep. 30, 2013 Duke Energy Indiana [Member]	Jun. 30, 2013 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Sep. 30, 2014 Duke Energy Indiana [Member] Financial Transmission Rights [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Duke Energy Indiana [Member] Financial Transmission Rights [Member] RTO Auction Pricing [Member]	Sep. 30, 2014 Duke Energy Indiana [Member] Financial Transmission Rights [Member] Minimum [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Duke Energy Indiana [Member] Financial Transmission Rights [Member] Minimum [Member] RTO Auction Pricing [Member]	Sep. 30, 2014 Duke Energy Indiana [Member] Financial Transmission Rights [Member] Maximum [Member] RTO Auction Pricing [Member]	Dec. 31, 2013 Duke Energy Indiana [Member] Financial Transmission Rights [Member] Maximum [Member] RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ (22)	$ 22	$ 13	$ (38)	$ (87)	$ (85)	$ (33)	$ (2)					$ (2)			$ 22	$ 12					$ (2)	$ 23					$ 5	$ 4					$ (14)	$ (22)		$ (3)	$ (2)	$ (4)	$ (4)	$ (12)	$ (2)							$ (35)	$ (38)					$ (35)	$ (38)	$ (55)	$ (28)	$ (4)	$ (6)	$ (19)	$ (6)	$ (33)	$ (2)					$ (10)	$ 18					$ (12)	$ (20)	$ 22	$ 45	$ 12	$ 14	$ 18	$ 10	$ 22	$ 12
Fair Value Inputs Price Per MMBtu									2.45	3.07	4.66	5.37																																																					2.45	3.07	4.66	5.37
Fair value inputs, price per MWh														25.79	52.38			(2.47)	(0.30)	12.92	13.80			25.18	20.77	59.17	58.90																25.79	52.38																											25.35	20.77	59.60	58.90											(2.47)	(0.30)	12.92	13.80
Fair Value Inputs Price Per MW day																														28.60	30.40	189.25	165.10

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- Definition

Price per MMBtu, used as an input to measure fair value for power sale agreements.

+ References

No definition available.

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- Definition

Price per MW day, used as an input to measure fair value for power sale agreements.

+ References

No definition available.

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- Definition

Price per MWh, used as an input to measure fair value for power sale agreements.

+ References

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- Definition

Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19279-110258



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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