Quarterly Financial Data (Unusual or Infrequently Occurring Items) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	$ (72)	$ (88)	$ (82)	$ (55)	$ (164)	$ (457)	$ (7)	$ (8)	$ (297)	$ (636)
Pretax impairment charge									(399)	(666)	(335)
Voluntary Opportunity Plan deferral								101		101
Total	(24)	(88)	(464)	(55)	(192)	(637)	(7)	(327)	(631)	(1,163)
Edwardsport IGCC Plant [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge					(28)	(180)	0	(420)		(628)
DukeNet [Member]
Quarterly Financial Information Disclosure [Line Items]
Gain on sale of equity investment	105	0	0	0					105
Crystal River Unit 3 Retirement [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	(57)	0	(295)	0					(352)
Nuclear Development Charges [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	0	0	(87)	0					(87)
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(29)	(34)	(35)	(22)	(46)	(184)	(5)	(4)	(120)	(239)
Pretax impairment charge										(31)	(12)
Voluntary Opportunity Plan deferral								101		101
Total					(46)	(184)	(5)	97		(138)
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(28)	(42)	(33)	(19)	(82)	(217)	(20)	(7)	(122)	(326)
Pretax impairment charge									(380)	(200)	(3)
Replacement power refund					0	(100)	0	0		(100)
Total	(85)	(42)	(415)	(19)	(274)	(317)	(20)	(7)	(561)	(618)
Progress Energy [Member] | Crystal River Unit 3 Retirement [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	(57)	0	(295)	0	(192)	0	0	0	(352)	(192)
Progress Energy [Member] | Nuclear Development Charges [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	0	0	(87)	0					(87)
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(19)	(32)	(22)	(11)	(36)	(180)	(12)	(4)	(84)	(232)
Pretax impairment charge									(22)	(54)	(3)
Total	(19)	(32)	(44)	(11)					(106)
Duke Energy Progress [Member] | Nuclear Development Charges [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	0	0	(22)	0					(22)
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(9)	(10)	(11)	(8)	(46)	(37)	(8)	(3)	(38)	(94)
Pretax impairment charge									(358)	(146)	0
Replacement power refund					0	(100)	0	0		(100)
Total	(66)	(10)	(371)	(8)	(238)	(137)	(8)	(3)	(455)	(386)
Duke Energy Florida [Member] | Crystal River Unit 3 Retirement [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	(57)	0	(295)	0	(192)	0	0	0	(352)	(192)
Duke Energy Florida [Member] | Nuclear Development Charges [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge	0	0	(65)	0					(65)
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(4)	(4)	(4)	(4)	(12)	(22)	(1)	(1)	(16)	(36)
Pretax impairment charge									(5)	(2)	(89)
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve the merger	(5)	(5)	(5)	(4)	(11)	(21)	(1)	(1)	(19)	(34)
Pretax impairment charge										(579)	(234)
Total					(39)	(201)	(1)	(421)		(662)
Duke Energy Indiana [Member] | Edwardsport IGCC Plant [Member]
Quarterly Financial Information Disclosure [Line Items]
Pretax impairment charge					$ (28)	$ (180)	$ 0	$ (420)		$ (628)