Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 1,924			$ 1,884
Gross Unrealized Holding Losses	36			47
Estimated Fair Value	5,611			5,551
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	31		31
Realized losses	4		7
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,890			1,852
Gross Unrealized Holding Losses	28			36
Estimated Fair Value	5,232			5,133
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	114			110
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,854			1,813
Gross Unrealized Holding Losses	14			10
Estimated Fair Value	3,623			3,579
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	11			8
Gross Unrealized Holding Losses	3			6
Estimated Fair Value	449			400
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			2
Gross Unrealized Holding Losses	3			6
Estimated Fair Value	139			160
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10			7
Gross Unrealized Holding Losses	7			12
Estimated Fair Value	708			730
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12			22
Gross Unrealized Holding Losses	1			2
Estimated Fair Value	199			154
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	34	[1]		32	[1]
Gross Unrealized Holding Losses	8	[1]		11	[1]
Estimated Fair Value	379	[1]		418	[1]
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	17			21
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	30			29
Estimated Fair Value	92			91
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Gross Unrealized Holding Losses	0			1
Estimated Fair Value	72			99
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			2
Gross Unrealized Holding Losses	1			2
Estimated Fair Value	79			79
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	12			17
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	7			8
Estimated Fair Value	107			111
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,023			1,004
Gross Unrealized Holding Losses	17			23
Estimated Fair Value	2,903			2,837
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	23		25
Realized losses	1		4
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,023			1,004
Gross Unrealized Holding Losses	16			22
Estimated Fair Value	2,900			2,834
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	70			42
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,001			974
Gross Unrealized Holding Losses	8			6
Estimated Fair Value	1,982			1,964
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6			5
Gross Unrealized Holding Losses	3			5
Estimated Fair Value	313			274
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1			2
Estimated Fair Value	33			54
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4			3
Gross Unrealized Holding Losses	4			7
Estimated Fair Value	309			354
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12			22
Gross Unrealized Holding Losses				2
Estimated Fair Value	193			146
Duke Energy Carolinas [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	[2]		1	[2]
Estimated Fair Value	3	[2]		3	[2]
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	3			3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	869			849
Gross Unrealized Holding Losses	12			14
Estimated Fair Value	2,388			2,358
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	7		5
Realized losses	2		2
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	867			848
Gross Unrealized Holding Losses	12			14
Estimated Fair Value	2,332			2,299
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	44			68
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	853			839
Gross Unrealized Holding Losses	6			4
Estimated Fair Value	1,641			1,615
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5			3
Gross Unrealized Holding Losses				1
Estimated Fair Value	136			126
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			2
Gross Unrealized Holding Losses	2			4
Estimated Fair Value	106			106
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6			4
Gross Unrealized Holding Losses	3			5
Estimated Fair Value	399			376
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1
Estimated Fair Value	6			8
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	[1]		1	[1]
Estimated Fair Value	56	[1]		59	[1]
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	16			20
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2			1
Estimated Fair Value	40			39
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	556			544
Gross Unrealized Holding Losses	10			11
Estimated Fair Value	1,569			1,540
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	6		2
Realized losses	2		1
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	556			544
Gross Unrealized Holding Losses	10			11
Estimated Fair Value	1,569			1,538
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	33			48
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	544			535
Gross Unrealized Holding Losses	4			3
Estimated Fair Value	1,088			1,069
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4			3
Gross Unrealized Holding Losses				1
Estimated Fair Value	87			80
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			2
Gross Unrealized Holding Losses	2			4
Estimated Fair Value	104			104
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5			4
Gross Unrealized Holding Losses	3			3
Estimated Fair Value	254			232
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1
Estimated Fair Value	3			5
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value				2	[1]
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value				2
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	313			305
Gross Unrealized Holding Losses	2			3
Estimated Fair Value	805			803
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	1		3
Realized losses	1		1
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	311			304
Gross Unrealized Holding Losses	2			3
Estimated Fair Value	763			761
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	11			20
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	309			304
Gross Unrealized Holding Losses	2			1
Estimated Fair Value	553			546
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1
Estimated Fair Value	49			46
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2			2
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses				2
Estimated Fair Value	145			144
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3			3
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	[1]		1	[1]
Estimated Fair Value	42	[1]		42	[1]
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2			3
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2			1
Estimated Fair Value	40			39
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	25			24
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	95			94
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	25	[1]		24	[1]
Gross Unrealized Holding Losses	1	[1]		1	[1]
Estimated Fair Value	95	[1]		94	[1]
Duke Energy Indiana [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1			1
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	25			24
Estimated Fair Value	66			65
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	$ 28			$ 28

[1] These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.

[2] These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.