Acquisitions and Sales of Other Assets (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended						6 Months Ended	12 Months Ended			12 Months Ended		3 Months Ended										12 Months Ended			3 Months Ended								12 Months Ended			3 Months Ended								12 Months Ended			3 Months Ended								12 Months Ended			3 Months Ended								12 Months Ended			0 Months Ended	3 Months Ended								12 Months Ended			0 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	Dec. 31, 2012 Commercial Power [Member]	Dec. 31, 2012 Excluded From Pro Forma [Member]	Dec. 31, 2011 Excluded From Pro Forma [Member]	Jun. 30, 2012 D S Cornerstone [Member]	Dec. 31, 2012 Progress Merger [Member]	Jul. 02, 2012 Progress Merger [Member]	Dec. 31, 2013 Progress Merger [Member] Purchase Price Allocation Adjustments [Member]	Dec. 31, 2012 Ibener [Member]	Mar. 31, 2014 Midwest Generation Business [Member] Scenario Forecast [Member]	Mar. 31, 2014 Minimum [Member] Midwest Generation Business [Member] Scenario Forecast [Member]	Mar. 31, 2014 Maximum [Member] Midwest Generation Business [Member] Scenario Forecast [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member]	Jun. 30, 2013 Duke Energy Carolinas [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Sep. 30, 2012 Duke Energy Carolinas [Member]	Jun. 30, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2012 Duke Energy Carolinas [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member]	Dec. 31, 2013 Progress Energy [Member]	Sep. 30, 2013 Progress Energy [Member]	Jun. 30, 2013 Progress Energy [Member]	Mar. 31, 2013 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Sep. 30, 2012 Progress Energy [Member]	Jun. 30, 2012 Progress Energy [Member]	Mar. 31, 2012 Progress Energy [Member]	Dec. 31, 2013 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Dec. 31, 2011 Progress Energy [Member]	Dec. 31, 2013 Duke Energy Progress [Member]	Sep. 30, 2013 Duke Energy Progress [Member]	Jun. 30, 2013 Duke Energy Progress [Member]	Mar. 31, 2013 Duke Energy Progress [Member]	Dec. 31, 2012 Duke Energy Progress [Member]	Sep. 30, 2012 Duke Energy Progress [Member]	Jun. 30, 2012 Duke Energy Progress [Member]	Mar. 31, 2012 Duke Energy Progress [Member]	Dec. 31, 2013 Duke Energy Progress [Member]	Dec. 31, 2012 Duke Energy Progress [Member]	Dec. 31, 2011 Duke Energy Progress [Member]	Dec. 31, 2013 Duke Energy Florida [Member]	Sep. 30, 2013 Duke Energy Florida [Member]	Jun. 30, 2013 Duke Energy Florida [Member]	Mar. 31, 2013 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]	Sep. 30, 2012 Duke Energy Florida [Member]	Jun. 30, 2012 Duke Energy Florida [Member]	Mar. 31, 2012 Duke Energy Florida [Member]	Dec. 31, 2013 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]	Dec. 31, 2011 Duke Energy Florida [Member]	Dec. 31, 2013 Duke Energy Ohio [Member]	Sep. 30, 2013 Duke Energy Ohio [Member]	Jun. 30, 2013 Duke Energy Ohio [Member]	Mar. 31, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Sep. 30, 2012 Duke Energy Ohio [Member]	Jun. 30, 2012 Duke Energy Ohio [Member]	Mar. 31, 2012 Duke Energy Ohio [Member]	Dec. 31, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Dec. 31, 2011 Duke Energy Ohio [Member]	Jan. 12, 2012 Duke Energy Ohio [Member] Duke Energy Vermillion [Member]	Dec. 31, 2013 Duke Energy Indiana [Member]	Sep. 30, 2013 Duke Energy Indiana [Member]	Jun. 30, 2013 Duke Energy Indiana [Member]	Mar. 31, 2013 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Sep. 30, 2012 Duke Energy Indiana [Member]	Jun. 30, 2012 Duke Energy Indiana [Member]	Mar. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2013 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2011 Duke Energy Indiana [Member]	Jan. 12, 2012 Duke Energy Indiana [Member] Duke Energy Vermillion [Member]
Significant Acquisitions and Disposals [Line Items]
Costs to achieve the merger	$ 72,000,000	$ 88,000,000	$ 82,000,000	$ 55,000,000	$ 164,000,000	$ 457,000,000	$ 7,000,000	$ 8,000,000	$ 297,000,000	$ 636,000,000			$ 413,000,000	$ 85,000,000									$ 29,000,000	$ 34,000,000	$ 35,000,000	$ 22,000,000	$ 46,000,000	$ 184,000,000	$ 5,000,000	$ 4,000,000	$ 120,000,000	$ 239,000,000		$ 28,000,000	$ 42,000,000	$ 33,000,000	$ 19,000,000	$ 82,000,000	$ 217,000,000	$ 20,000,000	$ 7,000,000	$ 122,000,000	$ 326,000,000		$ 19,000,000	$ 32,000,000	$ 22,000,000	$ 11,000,000	$ 36,000,000	$ 180,000,000	$ 12,000,000	$ 4,000,000	$ 84,000,000	$ 232,000,000		$ 9,000,000	$ 10,000,000	$ 11,000,000	$ 8,000,000	$ 46,000,000	$ 37,000,000	$ 8,000,000	$ 3,000,000	$ 38,000,000	$ 94,000,000		$ 4,000,000	$ 4,000,000	$ 4,000,000	$ 4,000,000	$ 12,000,000	$ 22,000,000	$ 1,000,000	$ 1,000,000	$ 16,000,000	$ 36,000,000			$ 5,000,000	$ 5,000,000	$ 5,000,000	$ 4,000,000	$ 11,000,000	$ 21,000,000	$ 1,000,000	$ 1,000,000	$ 19,000,000	$ 34,000,000
Proceeds												187,000,000																																																																		82,000,000
Transfer of Vermillion Generating Station																																																																												(28,000,000)												26,000,000
Capital expenditures									5,526,000,000	5,501,000,000	4,363,000,000																				1,695,000,000	1,908,000,000	2,272,000,000									2,490,000,000	2,366,000,000	2,256,000,000									1,567,000,000	1,525,000,000	1,426,000,000									915,000,000	809,000,000	813,000,000									434,000,000	514,000,000	499,000,000										545,000,000	718,000,000	1,066,000,000	68,000,000
Equity ownership interest															50.00%																																																																											62.50%
Construction and 12-year amortizing term loan facility	8,000,000				8,000,000				8,000,000	8,000,000					330,000,000																																																				8,000,000				8,000,000				8,000,000	8,000,000
Proceeds from issuance of other long-term debt															319,000,000
Business combination, pro forma information, revenue of acquiree since acquisition date, actual																4,943,000,000
Business combination, pro forma information, earnings or loss of acquiree since acquisition date, actual																368,000,000
Cash paid																			415,000,000
Property, plant and equipment																	23,141,000,000	(138,000,000)	383,000,000
Intangibles																			30,000,000
Deferred tax																			57,000,000
Working capital																	3,204,000,000		8,000,000
Bridge loan																			190,000,000
Goodwill	16,340,000,000				16,365,000,000				16,340,000,000	16,365,000,000							12,469,000,000	2,000,000	54,000,000															3,655,000,000				3,655,000,000				3,655,000,000	3,655,000,000																								920,000,000				921,000,000				920,000,000	921,000,000
Revolving loan under credit agreement																			200,000,000
Secured debt issuances	2,559,000,000				1,873,000,000				2,559,000,000	1,873,000,000													400,000,000				300,000,000				400,000,000	300,000,000		305,000,000				5,000,000				305,000,000	5,000,000		305,000,000				5,000,000				305,000,000	5,000,000
Other long-term assets, excluding goodwill																	9,990,000,000	(4,000,000)
Impairment charges									399,000,000	666,000,000	335,000,000										1,000,000,000	2,000,000,000										31,000,000	12,000,000									380,000,000	200,000,000	3,000,000									22,000,000	54,000,000	3,000,000									358,000,000	146,000,000	0									5,000,000	2,000,000	89,000,000											579,000,000	234,000,000
Assets held for sale																				$ 3,500,000,000