Fair Value (Nonrecurring Measurements) (Details) - USD ($)			1 Months Ended	3 Months Ended				6 Months Ended		8 Months Ended		9 Months Ended	12 Months Ended
		Oct. 02, 2015	Feb. 09, 2015	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Aug. 31, 2016	Aug. 28, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 01, 2015
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges													$ 1,096,000,000	$ 285,000,000	$ 91,000,000
Goodwill impairment expense													0	317,000,000	164,000,000
Other non-operating expense													2,000,000	0	128,000,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax														0	(51,000,000)
Kilroot [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring											$ 70,000,000
Other Asset Impairment Charges													0	121,000,000	0
UK Wind Development Projects [Domain]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring									$ 1,000,000
Other Asset Impairment Charges														37,000,000
DPL Subsidiary
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges				$ 624,000,000	$ 235,000,000								859,000,000	0	0
Goodwill impairment expense							$ 317,000,000
buffalo gap II [Member] [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring						$ 92,000,000
Other Asset Impairment Charges													159,000,000	0	0
buffalo gap III [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring												$ 118,000,000
Other Asset Impairment Charges													0	116,000,000	0
Sul Subsidiary [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax				602,000,000									(1,385,000,000)
Buffalo Gap
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring				36,000,000									36,000,000
Other Asset Impairment Charges													77,000,000	0	$ 0
Estimate of Fair Value Measurement [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring				320,000,000									320,000,000
Equity Method Investments [Member] | Solar Spain [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other non-operating expense	[1]		$ 0
Equity Method Investments [Member] | Estimate of Fair Value Measurement [Member] | Solar Spain [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[1]		0
Equity Method Investments [Member] | Estimate of Fair Value Measurement [Member] | Solar Spain [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[1]		0
Equity Method Investments [Member] | Estimate of Fair Value Measurement [Member] | Solar Spain [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[1]		29,000,000
Equity Method Investments [Member] | Reported Value Measurement [Member] | Solar Spain [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[1],[2]		$ 29,000,000
Discontinued Operations, Disposed of by Sale [Member] | Sul Subsidiary [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	[3]							$ (783,000,000)
Discontinued Operations, Disposed of by Sale [Member] | Estimate of Fair Value Measurement [Member] | Sul Subsidiary [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[3]				0			0
Discontinued Operations, Disposed of by Sale [Member] | Estimate of Fair Value Measurement [Member] | Sul Subsidiary [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[3]				470,000,000			470,000,000
Discontinued Operations, Disposed of by Sale [Member] | Estimate of Fair Value Measurement [Member] | Sul Subsidiary [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[3]				0			0
Discontinued Operations, Disposed of by Sale [Member] | Reported Value Measurement [Member] | Sul Subsidiary [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[3]				1,581,000,000			1,581,000,000
Long Lived Assets Held And Used [Member] | Kilroot [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]										121,000,000
Long Lived Assets Held And Used [Member] | Other Entities [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]													11,000,000
Long Lived Assets Held And Used [Member] | UK Wind Development Projects [Domain]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]								37,000,000
Long Lived Assets Held And Used [Member] | DPL Subsidiary
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]							235,000,000					624,000,000
Long Lived Assets Held And Used [Member] | buffalo gap II [Member] [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]					159,000,000
Long Lived Assets Held And Used [Member] | buffalo gap III [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]											116,000,000
Long Lived Assets Held And Used [Member] | Buffalo Gap
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Other Asset Impairment Charges	[4]									$ 77,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Kilroot [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]										0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Kilroot [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]										0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Kilroot [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]										70,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Other Entities [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]						0							0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Other Entities [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]						21,000,000							21,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Other Entities [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]						$ 0							$ 0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | UK Wind Development Projects [Domain] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]								0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | UK Wind Development Projects [Domain] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]								1,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | UK Wind Development Projects [Domain] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]								0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | DPL Subsidiary | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]			0	0			0					0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | DPL Subsidiary | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]			60,000,000	0			0					60,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | DPL Subsidiary | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4],[5]			103,000,000	89,000,000			89,000,000					103,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap II [Member] [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]					0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap II [Member] [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]					0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap II [Member] [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]					92,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap III [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]											0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap III [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]											0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | buffalo gap III [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]											118,000,000
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Buffalo Gap | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]									0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Buffalo Gap | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]									0
Long Lived Assets Held And Used [Member] | Estimate of Fair Value Measurement [Member] | Buffalo Gap | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[4]									36,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | Kilroot [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]										$ 191,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | Other Entities [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]											32,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | UK Wind Development Projects [Domain]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]								$ 38,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | DPL Subsidiary
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]			$ 787,000,000	$ 324,000,000			$ 324,000,000					$ 787,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | buffalo gap II [Member] [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]					$ 251,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | buffalo gap III [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]											$ 234,000,000
Long Lived Assets Held And Used [Member] | Reported Value Measurement [Member] | Buffalo Gap
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[4]									$ 113,000,000
Goodwill [Member] | DP&L [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Goodwill impairment expense	[6]	$ 317,000,000
Goodwill [Member] | Estimate of Fair Value Measurement [Member] | DP&L [Member] | Level 1
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[6]															$ 0
Goodwill [Member] | Estimate of Fair Value Measurement [Member] | DP&L [Member] | Level 2
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[6]															0
Goodwill [Member] | Estimate of Fair Value Measurement [Member] | DP&L [Member] | Level 3
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[6]															0
Goodwill [Member] | Reported Value Measurement [Member] | DP&L [Member]
Fair Value Assets Measured On Nonrecurring Basis Unobservable Inputs [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	[2],[6]															$ 317,000,000

[1] See Note 7—Investments In and Advances to Affiliates for further information.

[2] Represents the carrying values at the dates of measurement, before fair value adjustment.

[3] Per the Company's policy, pre-tax loss was limited to the impairment of long-lived assets. Upon disposal of AES Sul, we incurred an additional pre-tax loss on sale of $602 million. See Note 22—Discontinued Operations for further information.

[4] See Note 20—Asset Impairment Expense for further information.

[5] See Note 20—Asset Impairment Expense for further discussion of each DPL impairment.

[6] See Note 9—Goodwill and Other Intangible Assets for further information.