Fair Value of Financial Assets and Liabilities (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2013

Mar. 31, 2012

Dec. 31, 2012

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Investments in available-for-sale auction rate securities(a)		$	28	$	―	$	―	$	28
Nuclear decommissioning trust fund equity securities			3,104		3,026		57		21
Nuclear decommissioning trust fund debt securities			1,432		356		1,027		49
Other trading and available-for-sale equity securities(b)			93		84		9		―
Other trading and available-for-sale debt securities(c)			634		94		540		―
Derivative assets(b)			75		1		20		54
	Total assets		5,366		3,561		1,653		152
Derivative liabilities(d)			(611)		(77)		(398)		(136)
	Net assets	$	4,755	$	3,484	$	1,255	$	16

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Investments in available-for-sale auction rate securities(a)		$	29	$	―	$	―	$	29
Nuclear decommissioning trust fund equity securities			2,837		2,762		54		21
Nuclear decommissioning trust fund debt securities			1,405		317		1,040		48
Other trading and available-for-sale equity securities(b)			72		63		9		―
Other trading and available-for-sale debt securities(c)			602		40		562		―
Derivative assets(b)			103		18		22		63
	Total assets		5,048		3,200		1,687		161
Derivative liabilities(d)			(756)		(17)		(591)		(148)
	Net assets	$	4,292	$	3,183	$	1,096	$	13
(a)	Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Included in Other within Current Assets and Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.
(c)	Included in Other within Investments and Other Assets and Short-term Investments on the Condensed Consolidated Balance Sheets.
(d)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31, 2013
(in millions)			Available-for-Sale Auction Rate Securities		Available-for-Sale NDTF Investments		Derivatives (net)		Total
Balance at December 31, 2012			$	29	$	69	$	(85)	$	13
	Total pre-tax realized or unrealized gains (losses) included in earnings:
		Regulated electric		―		―		(6)		(6)
		Revenue, nonregulated electric, natural gas, and other		―		―		(4)		(4)
	Total pre-tax gains included in other comprehensive income:
		Losses on available for sale securities and other		(1)		―		―		(1)
	Purchases, sales, issuances and settlements:
		Issuances		―		―		6		6
		Settlements		―		―		7		7
	Total gains included on the Consolidated Balance Sheet as regulatory asset or liability			―		1		―		1
Balance at March 31, 2013			$	28	$	70	$	(82)	$	16
Pre-tax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013
		Regulated electric	$	―	$	―	$	1		1
		Revenue, nonregulated electric, natural gas, and other		―		―		(10)		(10)
Total			$	―	$	―	$	(9)	$	(9)

			Three Months Ended March 31, 2012
(in millions)			Available-for-Sale Auction Rate Securities		Available-for-Sale NDTF Investments		Derivatives (net)		Total
Balance at December 31, 2011			$	71	$	53	$	(39)	$	85
	Total pre-tax realized or unrealized gains (losses) included in earnings:
		Regulated electric		―		―		8		8
		Revenue, nonregulated electric, natural gas, and other		―		―		(2)		(2)
	Total pre-tax gains included in other comprehensive income:
		Gains on available for sale securities and other		1		―		―		1
	Purchases, sales, issuances and settlements:
		Purchases		―		2		―		2
		Settlements		―		―		(9)		(9)
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			―		1		―		1
Balance at March 31, 2012			$	72	$	56	$	(42)	$	86

Schedule of Long-term debt, including current

		March 31, 2013				December 31, 2012
(in millions)		Book Value		Fair Value		Book Value		Fair Value
Duke Energy (a)		$	39,662	$	44,068	$	39,461	$	44,001
Duke Energy Carolinas(b)			8,740		10,036		8,741		10,096
Progress Energy			14,224		16,276		14,428		16,563
Duke Energy Progress			5,336		5,757		4,840		5,277
Duke Energy Florida			4,894		5,730		5,320		6,222
Duke Energy Ohio			1,994		2,142		1,997		2,117
Duke Energy Indiana			3,702		4,228		3,702		4,268
(a)	Includes book value of Non-recourse long-term debt of variable interest entities of $1,255 million and $852 million March 31, 2013 and December 31, 2012, respectively.
(b)	Includes book value of Non-recourse long-term debt of variable interest entities of $300 million at both March 31, 2013 and December 31, 2012, respectively.

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43

Duke Energy Carolinas [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

			March 31, 2013
(in millions)			Total Fair Value	Level 1		Level 2		Level 3
Investments in available-for-sale auction rate securities(a)		$	3	$	―	$	―	$	3
Nuclear decommissioning trust fund equity securities			1,734		1,663		50		21
Nuclear decommissioning trust fund debt securities			785		180		556		49
	Total assets	$	2,522	$	1,843	$	606	$	73
Derivative liabilities(b)			(5)		―		―		(5)
	Net assets	$	2,517	$	1,843	$	606	$	68

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Investments in available-for-sale auction rate securities(a)		$	3	$	―	$	―	$	3
Nuclear decommissioning trust fund equity securities			1,592		1,523		48		21
Nuclear decommissioning trust fund debt securities			762		155		559		48
	Total assets	$	2,357	$	1,678	$	607	$	72
Derivative liabilities(b)			(12)		―		―		(12)
	Net Assets	$	2,345	$	1,678	$	607	$	60
(a)	Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31,2013
			Available-for-Sale Auction Rate Securities		Available-for-Sale NDTF Investments		Derivatives (net)		Total
Balance at December 31, 2012			$	3	$	69	$	(12)	$	60
	Purchases, sales, issuances and settlements:
		Settlements		―		―		7		7
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			―		1		―		1
Balance at March 31, 2013			$	3	$	70	$	(5)	$	68
Pre-tax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013
		Regulated electric	$	―	$	―	$	(5)		(5)
Total			$	―	$	―	$	(5)	$	(5)

			Three Months Ended March 31, 2012
			Available-for-Sale Auction Rate Securities		Available-for-Sale NDTF Investments		Derivatives (net)		Total
Balance at December 31, 2011			$	12	$	53	$	―	$	65
	Purchases, sales, issuances and settlements:
		Purchases		―		2		―		2
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			―		1		―		1
Balance at March 31, 2012			$	12	$	56	$	―	$	68

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43

Progress Energy [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	1,369	$	1,363	$	6	$	―
Nuclear decommissioning trust fund debt securities and other			648		177		471		―
Other trading and available-for-sale debt securities and other(a)			60		20		40		―
Derivative assets(b)			15		―		15		―
	Total assets		2,092		1,560		532		―
Derivative liabilities(c)			(269)		―		(238)		(31)
	Net assets	$	1,823	$	1,560	$	294	$	(31)

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	1,245	$	1,239	$	6	$	―
Nuclear decommissioning trust fund debt securities and other			643		162		481		―
Other trading and available-for-sale debt securities and other(a)			57		17		40		―
Derivative assets(b)			11		―		11		―
	Total assets		1,956		1,418		538		―
Derivative liabilities(c)			(440)		―		(402)		(38)
	Net assets	$	1,516	$	1,418	$	136	$	(38)
(a)	Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b)	Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(c)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31, 2013
(in millions)			Derivatives (net)
Balance at December 31, 2012			$	(38)
	Purchases, sales, issuances and settlements:
		Issuances		6
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			1
Balance at March 31, 2013			$	(31)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013
		Regulated electric	$	6
Total			$	6

		Three Months Ended March 31, 2012
(in millions)		Derivatives (net)
Balance at December 31, 2011		$	(24)
	Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability		(3)
Balance at March 31, 2012		$	(27)

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43

Duke Energy Progress [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	894	$	894	$	―	$	―
Nuclear decommissioning trust fund debt securities and other			453		123		330		―
Other trading and available-for-sale debt securities and other(a)			4		4		―		―
Derivative assets(b)			5		―		5		―
	Total assets		1,356		1,021		335		―
Derivative liabilities(c)			(98)		―		(67)		(31)
	Net assets	$	1,258	$	1,021	$	268	$	(31)

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	811	$	811	$	―	$	―
Nuclear decommissioning trust fund debt securities and other			448		119		329		―
Other trading and available-for-sale debt securities and other(a)			3		3		―		―
Derivative assets(b)			2		―		2		―
	Total assets		1,264		933		331		―
Derivative liabilities(c)			(166)		―		(128)		(38)
	Net assets	$	1,098	$	933	$	203	$	(38)
(a)	Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b)	Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(c)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31, 2013
(in millions)			Derivatives (net)
Balance at December 31, 2012			$	(38)
	Purchases, sales, issuances and settlements:
		Issuances		6
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			1
Balance at March 31, 2013			$	(31)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013
		Regulated electric	$	6
Total			$	6

		Three Months Ended March 31, 2012
(in millions)		Derivatives (net)
Balance at December 31, 2011		$	(24)
	Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability		(3)
Balance at March 31, 2012		$	(27)

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43

Duke Energy Florida [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	474	$	468	$	6	$	―
Nuclear decommissioning trust fund debt securities and other			196		54		142		―
Other trading and available-for-sale debt securities and other(a)			45		5		40		―
Derivative assets(b)			10		―		10		―
	Total assets		725		527		198		―
Derivative liabilities(c)			(167)		―		(167)		―
	Net assets	$	558	$	527	$	31	$	―

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Nuclear decommissioning trust fund equity securities		$	435	$	429	$	6	$	―
Nuclear decommissioning trust fund debt securities and other			194		43		151		―
Other trading and available-for-sale debt securities and other(a)			43		3		40		―
Derivative assets(b)			9		―		9		―
	Total assets		681		475		206		―
Derivative liabilities(c)			(270)		―		(270)		―
	Net assets (liabilities)	$	411	$	475	$	(64)	$	―
(a)	Included in Other within Investments and Other Assets in the Condensed Balance Sheets.
(b)	Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Balance Sheets.
(c)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Balance Sheets

Duke Energy Ohio [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Derivative assets(a)		$	19	$	8	$	2	$	9
Derivative liabilities(b)			(94)		(72)		(8)		(14)
	Net liabilities	$	(75)	$	(64)	$	(6)	$	(5)

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Derivative assets(a)		$	59	$	48	$	2	$	9
Derivative liabilities(b)			(38)		(15)		(8)		(15)
	Net assets (liabilities)	$	21	$	33	$	(6)	$	(6)
(a)	Included in Other within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31, 2013
(in millions)			Derivatives (net)
Balance at December 31, 2012			$	(6)
	Total pre-tax realized or unrealized gains (losses) included in earnings:
		Revenue, nonregulated electric, natural gas, and other		4
	Purchases, sales, issuances and settlements:
		Settlements		(3)
Balance at March 31, 2013			$	(5)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013:
		Revenue, non-regulated electric and other	$	(2)
Total			$	(2)

			Three Months Ended March 31, 2012
(in millions)			Derivatives (net)
Balance at December 31, 2011			$	(3)
	Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			(1)
Balance at March 31, 2012			$	(4)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2012:
		Revenue, non-regulated electric and other	$	1
Total			$	1

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43

Duke Energy Indiana [Member]

Fair Value Disclosures [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

		March 31, 2013
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Available-for-sale equity securities(a)		$	54	$	54	$	―	$	―
Available-for-sale debt securities(a)			29		―		29		―
Derivative assets(b)			5		1		―		4
	Total assets		88		55		29	$	4
Derivative liabilities(c)			(55)		―		(55)		―
	Net assets (liabilities)	$	33	$	55	$	(26)	$	4

		December 31, 2012
(in millions)		Total Fair Value		Level 1		Level 2		Level 3
Available-for-sale equity securities(a)		$	49	$	49	$	―	$	―
Available-for-sale debt securities(a)			29		―		29		―
Derivative assets(b)			10		―		―		10
	Total assets		88		49		29	$	10
Derivative liabilities(c)			(63)		―		(63)		―
	Net assets (liabilities)	$	25	$	49	$	(34)	$	10
(a)	Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Included in Other within Current Assets on the Condensed Consolidated Balance Sheets.
(c)	Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.

Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs

			Three Months Ended March 31, 2013
(in millions)			Derivatives (net)
Balance at December 31, 2012			$	10
	Total pre-tax realized or unrealized gains (losses) included in earnings:
		Regulated electric		(5)
	Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			(1)
Balance at March 31, 2013			$	4

			Three Months Ended March 31, 2012
(in millions)			Derivatives (net)
Balance at December 31, 2011			$	4
	Total pre-tax realized or unrealized gains (losses) included in earnings:
		Regulated electric		8
	Purchases, sales, issuances and settlements:
		Settlements		(10)
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability			1
Balance at March 31, 2012			$	3

Quantitative Information Table - Level 3

	March 31, 2013
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(85)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.84	$	10.30
FERC mitigation power sale agreements		(10)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	54.56
Financial transmission rights (FTRs)		4	RTO market pricing	FTR price		(0.42)	-	12.72
Commodity power contracts		17	Discounted cash flow	Forward electricity curves - price per MWh		28.40	-	81.60
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	122.64
Commodity capacity option contracts		2	Discounted cash flow	Forward capacity option curves - price per MW day		31.15	-	81.60
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(5)	Discounted cash flow	Forward electricity curves - price per MWh	$	28.18	-	54.56
Progress Energy
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Progress
Commodity natural gas contracts	$	(26)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.13	-	4.54
FERC mitigation power sale agreements		(5)	Discounted cash flow	Forward electricity curves - price per MWh		25.35	-	48.68
Duke Energy Ohio
Commodity power contracts	$	25	Discounted cash flow	Forward electricity curves - price per MWh	$	28.40	-	61.35
Commodity natural gas contracts		(23)	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.98	-	4.69
Reserves		(7)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	4	RTO market pricing	FTR price	$	(0.42)	$	12.72

	December 31, 2012
Investment Type	Fair Value (in millions)		Valuation Technique	Unobservable Input	Range
Duke Energy
Commodity natural gas contracts	$	(53)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	2.33	$	9.99
FERC mitigation power sale agreements		(23)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Financial transmission rights (FTRs)		11	RTO market pricing	FTR price		23.63	-	39.22
Commodity power contracts		(8)	Discounted cash flow	Forward electricity curves - price per MWh		24.82	-	77.96
Commodity capacity contracts		(3)	Discounted cash flow	Forward capacity curves - price per MW day		95.16	-	105.36
Commodity capacity option contracts		3	Discounted cash flow	Forward capacity option curves - price per MW day		4.68	-	77.96
Reserves		(12)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Carolinas
FERC mitigation power sale agreements	$	(12)	Discounted cash flow	Forward electricity curves - price per MWh	$	25.83	-	48.69
Progress Energy
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Progress
Commodity natural gas contracts	$	(27)	Discounted cash flow	Forward natural gas curves - price per MMBtu	$	4.07	-	4.45
FERC mitigation power sale agreements		(11)	Discounted cash flow	Forward electricity curves - price per MWh		25.83	-	48.69
Duke Energy Ohio
Financial transmission rights (FTRs)	$	1	RTO market pricing	FTR price	$	27.17	$	39.22
Commodity power contracts		(1)	Discounted cash flow	Forward electricity curves - price per MWh		25.90	-	57.50
Commodity natural gas contracts		5	Discounted cash flow	Forward natural gas curves - price per MMBtu		3.30	-	4.51
Reserves		(11)		Bid-ask spreads, implied volatility, probability of default
Duke Energy Indiana
Financial transmission rights (FTRs)	$	10	RTO market pricing	FTR price	$	23.63	$	35.43