Quarterly Financial Data (Unaudited) (Unusual or Infrequently Occurring Items) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	$ (208)	$ (84)	$ (111)	$ (120)	$ (30)	$ (24)	$ (22)	$ (21)	$ (523)	$ (97)
Asset Impairment Charges									(18)	(106)	$ (81)
Cost Savings Initiative	(29)	(19)	(24)	(20)	(142)				(92)	(142)
Total	(751)	(174)	(329)	(140)	(182)	(121)	(63)	(21)	(1,394)	(387)
Commercial Renewables Impairment [Member]
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charges		(71)							(71)
Edwardsport Settlement [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(3)	(90)				(93)
Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(7)	(7)				(14)
Midwest Generation Business [Member]
Quarterly Financial Information Disclosure [Line Items]
State Tax Adjustment related to Midwest Generation Sale							(41)			(41)
Central America Impairment [Member]
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charges			(194)						(194)
Intl Disposal Group [Member]
Quarterly Financial Information Disclosure [Line Items]
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax	514								514
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(68)	(13)	(12)	(11)	(16)	(11)	(11)	(9)	(104)	(47)
Asset Impairment Charges									(1)	(1)	(3)
Cost Savings Initiative	(11)	(8)	(10)	(10)	(93)				(39)	(93)
Total	(79)	(21)	(22)	(21)	(116)	(12)	(11)	(9)	(143)	(148)
Duke Energy Carolinas [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(7)	(1)				(8)
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(44)	(10)	(8)	(7)	(10)	(8)	(8)	(8)	(69)	(34)
Asset Impairment Charges									(7)	(12)	16
Cost Savings Initiative	(14)	(10)	(8)	(8)	(36)				(40)	(36)
Total	(58)	(20)	(16)	(15)	(46)	(14)	(8)	(8)	(109)	(76)
Progress Energy [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties						(6)				(6)
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(40)	(6)	(5)	(5)	(6)	(6)	(5)	(5)	(56)	(22)
Asset Impairment Charges									(1)	(5)	18
Cost Savings Initiative	(6)	(7)	(5)	(5)	(28)				(23)	(28)
Total	(46)	(13)	(10)	(10)	(34)	(12)	(5)	(5)	(79)	(56)
Duke Energy Progress [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties						(6)				(6)
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(4)	(4)	(3)	(2)	(4)	(3)	(3)	(3)	(13)	(13)
Asset Impairment Charges									(6)	(7)	(2)
Cost Savings Initiative	(9)	(3)	(3)	(2)	(8)				(17)	(8)
Total	(13)	(7)	(6)	(4)	(12)	(3)	(3)	(3)	(30)	(21)
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(2)	(2)	(1)	(1)	(1)	(1)	(1)	(1)	(6)	(4)
Asset Impairment Charges											$ (94)
Cost Savings Initiative	(1)		(1)	(1)	(2)				(3)	(2)
Total	(3)	(2)	(2)	(2)	(3)	(1)	(1)	(1)	(9)	(6)
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(3)	(3)	(2)	(1)	(2)	(2)	(1)	(2)	(9)	(7)
Asset Impairment Charges									(8)	(88)
Cost Savings Initiative	(1)	(1)	(4)	(1)	(6)				(7)	(6)
Total	$ (4)	$ (4)	$ (6)	$ (2)	(11)	(92)	$ (1)	$ (2)	$ (16)	(106)
Duke Energy Indiana [Member] | Edwardsport Settlement [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					$ (3)	$ (90)				$ (93)