Goodwill and Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill	$ 17,200us-gaap_GoodwillGross		$ 17,192us-gaap_GoodwillGross
Accumulated impairment charges	(871)		(871)
Foreign exchange and other changes	(16)
Goodwill, Acquired During Period	24us-gaap_GoodwillAcquiredDuringPeriod
Goodwill as adjusted for accumulated impairment charges	16,329us-gaap_Goodwill		16,321us-gaap_Goodwill
Asset impairment charges	0us-gaap_AssetImpairmentCharges	96us-gaap_AssetImpairmentCharges
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill	15,950		15,950
Goodwill as adjusted for accumulated impairment charges	15,950		15,950
International [Member]
Goodwill [Roll Forward]
Goodwill	291		307
Foreign exchange and other changes	(16)
Goodwill as adjusted for accumulated impairment charges	291		307
Commercial Power [Member]
Goodwill [Roll Forward]
Goodwill	959		935
Accumulated impairment charges	(871)		(871)
Goodwill, Acquired During Period	24
Goodwill as adjusted for accumulated impairment charges	88		64
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	2,324		2,324
Accumulated impairment charges	(1,404)		(1,404)
Goodwill as adjusted for accumulated impairment charges	920		920
Asset impairment charges		94
Duke Energy Ohio [Member] \| Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges		94	94
Duke Energy Ohio [Member] \| Regulated Utility [Member]
Goodwill [Roll Forward]
Goodwill	1,136		1,136
Accumulated impairment charges	(216)		(216)
Goodwill as adjusted for accumulated impairment charges	920		920
Duke Energy Ohio [Member] \| Commercial Power [Member]
Goodwill [Roll Forward]
Goodwill	1,188		1,188
Accumulated impairment charges	(1,188)		(1,188)
Goodwill as adjusted for accumulated impairment charges	0		0
Duke Energy Ohio [Member] \| Commercial Power [Member] \| Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges		$ 94

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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

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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.

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Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments 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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