Investments In Debt And Equity Securities (Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 1,461			$ 1,216
Gross Unrealized Holding Losses	33			30
Estimated Fair Value	5,277			4,932
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	31		21
Realized losses	7		2
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,439			1,199
Gross Unrealized Holding Losses	26			23
Estimated Fair Value	4,546			4,263
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	22	[1]		17	[1]
Gross Unrealized Holding Losses	7	[1]		7	[1]
Estimated Fair Value	731	[1]		669	[1]
Cash and Cash Equivalents [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	91			105
Cash and Cash Equivalents [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	21			17
Equity Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,380			1,132
Gross Unrealized Holding Losses	19			19
Estimated Fair Value	3,104			2,837
Equity Securities [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	16			10
Gross Unrealized Holding Losses				0
Estimated Fair Value	84			63
Corporate Debt Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	17			21
Gross Unrealized Holding Losses	2			1
Estimated Fair Value	333			338
Corporate Debt Securities [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			2
Gross Unrealized Holding Losses				0
Estimated Fair Value	347			381
Municipal Bonds [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10			12
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	189			194
Municipal Bonds [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4			4
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	75			70
US Treasury and Government [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	20			24
Gross Unrealized Holding Losses	2			1
Estimated Fair Value	666			625
US Treasury and Government [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains				0
Estimated Fair Value	73			23
Auction Rate Securities [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	6			6
Estimated Fair Value	28			29
Other Debt Obligations [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12			10
Gross Unrealized Holding Losses	2			1
Estimated Fair Value	163			164
Other Debt Obligations [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Estimated Fair Value	103			86
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	764			632
Gross Unrealized Holding Losses	10			9
Estimated Fair Value	2,520			2,364
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	25		20
Realized losses	4		2
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	764			632
Gross Unrealized Holding Losses	9			8
Estimated Fair Value	2,517			2,361
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] | Cash and Cash Equivalents [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	41			40
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	736			600
Gross Unrealized Holding Losses	4			5
Estimated Fair Value	1,735			1,592
Duke Energy Carolinas [Member] | Corporate Debt Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	9			11
Gross Unrealized Holding Losses	2			1
Estimated Fair Value	239			250
Duke Energy Carolinas [Member] | Municipal Bonds [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	0			2
Estimated Fair Value	21			40
Duke Energy Carolinas [Member] | US Treasury and Government [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8			10
Gross Unrealized Holding Losses	1
Estimated Fair Value	345			304
Duke Energy Carolinas [Member] | Auction Rate Securities [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	3			3
Duke Energy Carolinas [Member] | Other Debt Obligations [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	11			9
Gross Unrealized Holding Losses	2			2
Estimated Fair Value	136			135
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	678			570
Gross Unrealized Holding Losses	17			15
Estimated Fair Value	2,090			1,959
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	5		7
Realized losses	2		3
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	675			567
Gross Unrealized Holding Losses	17			15
Estimated Fair Value	2,029			1,902
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	[1]		3	[1]
Estimated Fair Value	61	[1]		57	[1]
Progress Energy [Member] | Cash and Cash Equivalents [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	50			65
Progress Energy [Member] | Cash and Cash Equivalents [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	21			17
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	644			532
Gross Unrealized Holding Losses	15			14
Estimated Fair Value	1,369			1,245
Progress Energy [Member] | Corporate Debt Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8			9
Estimated Fair Value	94			89
Progress Energy [Member] | Municipal Bonds [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10			11
Gross Unrealized Holding Losses	1			1
Estimated Fair Value	168			154
Progress Energy [Member] | Municipal Bonds [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			3
Estimated Fair Value	40			40
Progress Energy [Member] | US Treasury and Government [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12			14
Gross Unrealized Holding Losses	1
Estimated Fair Value	321			321
Progress Energy [Member] | Other Debt Obligations [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Estimated Fair Value	27			28
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	435			363
Gross Unrealized Holding Losses	12			11
Estimated Fair Value	1,360			1,278
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	2		5
Realized losses	1		2
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	435			363
Gross Unrealized Holding Losses	12			11
Estimated Fair Value	1,356			1,275
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	4	[1]		3	[1]
Duke Energy Progress [Member] | Cash and Cash Equivalents [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	39			55
Duke Energy Progress [Member] | Cash and Cash Equivalents [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	4			3
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	413			337
Gross Unrealized Holding Losses	11			11
Estimated Fair Value	894			811
Duke Energy Progress [Member] | Corporate Debt Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6			8
Estimated Fair Value	84			78
Duke Energy Progress [Member] | Municipal Bonds [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4			4
Estimated Fair Value	95			80
Duke Energy Progress [Member] | US Treasury and Government [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	11			13
Gross Unrealized Holding Losses	1
Estimated Fair Value	233			241
Duke Energy Progress [Member] | Other Debt Obligations [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Estimated Fair Value	11			10
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	243			207
Gross Unrealized Holding Losses	5			4
Estimated Fair Value	716			668
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	3		2
Realized losses	1		1
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	240			204
Gross Unrealized Holding Losses	5			4
Estimated Fair Value	673			627
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	[3]		3	[3]
Estimated Fair Value	43	[3]		41	[3]
Duke Energy Florida [Member] | Cash and Cash Equivalents [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	11			10
Duke Energy Florida [Member] | Cash and Cash Equivalents [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3			1
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	231			194
Gross Unrealized Holding Losses	4			4
Estimated Fair Value	475			434
Duke Energy Florida [Member] | Corporate Debt Securities [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2			1
Estimated Fair Value	10			11
Duke Energy Florida [Member] | Municipal Bonds [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6			7
Gross Unrealized Holding Losses	1			0
Estimated Fair Value	73			74
Duke Energy Florida [Member] | Municipal Bonds [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3			3
Estimated Fair Value	40			40
Duke Energy Florida [Member] | US Treasury and Government [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Estimated Fair Value	88			80
Duke Energy Florida [Member] | Other Debt Obligations [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	0			1
Estimated Fair Value	16			18
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	15			10
Gross Unrealized Holding Losses				0
Estimated Fair Value	83			78
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	15	[1]		10	[1]
Gross Unrealized Holding Losses				0	[1]
Estimated Fair Value	83	[1]		78	[1]
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	14			9
Gross Unrealized Holding Losses				0
Estimated Fair Value	54			50
Duke Energy Indiana [Member] | Municipal Bonds [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1			1
Estimated Fair Value	$ 29			$ 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.

[3] These amounts are recorded in Other within Investments and Other Assets on the Condensed Balance sheets.