Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 10. See Note 11 for additional information related to investments by major security type for the Duke Energy Registrants.

	September 30, 2017
(in millions)	Total Fair Value			Level 1		Level 2			Level 3			Not Categorized
NDTF equity securities	$	4,627		$	4,549	$	—		$	—		$	78
NDTF debt securities	2,167			617		1,550			—			—
Other trading and AFS equity securities	116			116		—			—			—
Other AFS debt securities	243			59		184			—			—
Derivative assets	69			4		35			30			—
Total assets	7,222			5,345		1,769			30			78
Derivative liabilities	(191		)	—		(68		)	(123		)	—
Net assets (liabilities)	$	7,031		$	5,345	$	1,701		$	(93	)	$	78

	December 31, 2016
(in millions)	Total Fair Value			Level 1			Level 2			Level 3			Not Categorized
NDTF equity securities	$	4,106		$	4,029		$	—		$	—		$	77
NDTF debt securities	2,078			632			1,446			—			—
Other trading and AFS equity securities	104			104			—			—			—
Other trading and AFS debt securities	266			75			186			5			—
Derivative assets	162			5			136			21			—
Total assets	6,716			4,845			1,768			26			77
Derivative liabilities	(252		)	(2		)	(63		)	(187		)	—
Net assets (liabilities)	$	6,464		$	4,843		$	1,705		$	(161	)	$	77

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

The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Cost of natural gas on the Duke Energy Registrants' Condensed Consolidated Statements of Operations and Comprehensive Income. Amounts included in changes of net assets on the Duke Energy Registrants' Condensed Consolidated Balance Sheets are included in regulatory assets or liabilities. All derivative assets and liabilities are presented on a net basis.

	Three Months Ended September 30, 2017								Three Months Ended September 30, 2016
(in millions)	Investments		Derivatives (net)			Total			Investments		Derivatives (net)			Total
Balance at beginning of period	$	—	$	(91	)	$	(91	)	$	4	$	34		$	38
Purchases, sales, issuances and settlements:
Settlements	—		(12		)	(12		)	—		(9		)	(9		)
Total gains (losses) included on the Condensed Consolidated Balance Sheet	—		10			10			—		(2		)	(2		)
Balance at end of period	$	—	$	(93	)	$	(93	)	$	4	$	23		$	27

	Nine Months Ended September 30, 2017									Nine Months Ended September 30, 2016
(in millions)	Investments			Derivatives (net)			Total			Investments			Derivatives (net)			Total
Balance at beginning of period	$	5		$	(166	)	$	(161	)	$	5		$	10		$	15
Total pretax realized or unrealized gains included in comprehensive income	1			—			1			—			—			—
Purchases, sales, issuances and settlements:
Purchases	—			55			55			—			34			34
Sales	(6		)	—			(6		)	(1		)	—			(1		)
Settlements	—			(30		)	(30		)	—			(22		)	(22		)
Total gains included on the Condensed Consolidated Balance Sheet	—			48			48			—			1			1
Balance at end of period	$	—		$	(93	)	$	(93	)	$	4		$	23		$	27

Quantitative Information Table - Level 3

The following tables include quantitative information about the Duke Energy Registrants' derivatives classified as Level 3.

	September 30, 2017
	Fair Value
Investment Type	(in millions)			Valuation Technique	Unobservable Input	Range
Duke Energy Ohio
Financial Transmission Rights (FTRs)	$	2		RTO auction pricing	FTR price – per megawatt-hour (MWh)	$	—		-	$	1.08
Duke Energy Indiana
FTRs	28			RTO auction pricing	FTR price – per MWh	(0.82		)	-	6.19
Piedmont
Natural gas contracts	(123		)	Discounted cash flow	Forward natural gas curves – price per million British thermal unit (MMBtu)	2.12			-	3.36
Duke Energy
Total Level 3 derivatives	$	(93	)

	December 31, 2016
	Fair Value
Investment Type	(in millions)			Valuation Technique	Unobservable Input	Range
Duke Energy Ohio
FTRs	$	5		RTO auction pricing	FTR price – per MWh	$	0.77		-	$	3.52
Duke Energy Indiana
FTRs	16			RTO auction pricing	FTR price – per MWh	(0.83		)	-	9.32
Piedmont
Natural gas contracts	(187		)	Discounted cash flow	Forward natural gas curves – price per MMBtu	2.31			-	4.18
Duke Energy
Total Level 3 derivatives	$	(166	)

Schedule Of Long Term Debt Fair Value

The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements.

	September 30, 2017				December 31, 2016
(in millions)	Book Value		Fair Value		Book Value		Fair Value
Duke Energy	$	51,414	$	53,985	$	47,895	$	49,161
Duke Energy Carolinas	9,525		10,653		9,603		10,494
Progress Energy	17,637		19,615		17,541		19,107
Duke Energy Progress	7,557		8,075		7,011		7,357
Duke Energy Florida	6,696		7,475		6,125		6,728
Duke Energy Ohio	2,067		2,242		1,884		2,020
Duke Energy Indiana	3,785		4,407		3,786		4,260
Piedmont	2,036		2,193		1,821		1,933

Duke Energy Carolinas [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017
(in millions)	Total Fair Value			Level 1		Level 2			Level 3		Not Categorized
NDTF equity securities	$	2,553		$	2,475	$	—		$	—	$	78
NDTF debt securities	1,060			178		882			—		—
Derivative assets	8			—		8			—		—
Total assets	3,621			2,653		890			—		78
Derivative liabilities	(25		)	—		(25		)	—		—
Net assets	$	3,596		$	2,653	$	865		$	—	$	78

	December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Level 3		Not Categorized
NDTF equity securities	$	2,245		$	2,168	$	—		$	—	$	77
NDTF debt securities	1,013			178		835			—		—
Other AFS debt securities	3			—		—			3		—
Derivative assets	33			—		33			—		—
Total assets	3,294			2,346		868			3		77
Derivative liabilities	(16		)	—		(16		)	—		—
Net assets	$	3,278		$	2,346	$	852		$	3	$	77

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

The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.

	Investments
	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions)	2017		2016		2017			2016
Balance at beginning of period	$	—	$	3	$	3		$	3
Total pretax realized or unrealized gains included in comprehensive income	—		—		1			—
Purchases, sales, issuances and settlements:
Sales	—		—		(4		)	—
Balance at end of period	$	—	$	3	$	—		$	3

Progress Energy [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	2,074		$	2,074	$	—		$	1,861		$	1,861	$	—
NDTF debt securities	1,107			439		668			1,065			454		611
Other AFS debt securities	58			11		47			65			21		44
Derivative assets	15			1		14			85			—		85
Total assets	3,254			2,525		729			3,076			2,336		740
Derivative liabilities	(22		)	—		(22		)	(25		)	—		(25		)
Net assets	$	3,232		$	2,525	$	707		$	3,051		$	2,336	$	715

Duke Energy Progress [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	1,683		$	1,683	$	—		$	1,505		$	1,505	$	—
NDTF debt securities	778			231		547			708			207		501
Other AFS debt securities	1			1		—			1			1		—
Derivative assets	8			1		7			46			—		46
Total assets	2,470			1,916		554			2,260			1,713		547
Derivative liabilities	(7		)	—		(7		)	(7		)	—		(7		)
Net assets	$	2,463		$	1,916	$	547		$	2,253		$	1,713	$	540

Duke Energy Florida [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	391		$	391	$	—		$	356		$	356	$	—
NDTF debt securities	329			208		121			357			247		110
Other AFS debt securities	47			—		47			48			4		44
Derivative assets	6			—		6			39			—		39
Total assets	773			599		174			800			607		193
Derivative liabilities	(9		)	—		(9		)	(12		)	—		(12		)
Net assets	$	764		$	599	$	165		$	788		$	607	$	181

Duke Energy Ohio [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 2			Level 3		Total Fair Value			Level 2			Level 3
Derivative assets	$	2		$	—		$	2	$	5		$	—		$	5
Derivative liabilities	(5		)	(5		)	—		(6		)	(6		)	—
Net (liabilities) assets	$	(3	)	$	(5	)	$	2	$	(1	)	$	(6	)	$	5

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

The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.

	Derivatives (net)
	Three Months Ended September 30,						Nine Months Ended September 30,
(in millions)	2017			2016			2017			2016
Balance at beginning of period	$	3		$	5		$	5		$	3
Purchases, sales, issuances and settlements:
Purchases	—			—			3			5
Settlements	(1		)	(2		)	(3		)	(4		)
Total losses included on the Condensed Consolidated Balance Sheet	—			—			(3		)	(1		)
Balance at end of period	$	2		$	3		$	2		$	3

Duke Energy Indiana [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value		Level 1		Level 2		Level 3		Total Fair Value			Level 1			Level 2		Level 3
Other AFS equity securities	$	91	$	91	$	—	$	—	$	79		$	79		$	—	$	—
Other AFS debt securities	31		—		31		—		31			—			31		—
Derivative assets	28		—		—		28		16			—			—		16
Total assets	150		91		31		28		126			79			31		16
Derivative liabilities	—		—		—		—		(2		)	(2		)	—		—
Net assets	$	150	$	91	$	31	$	28	$	124		$	77		$	31	$	16

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

The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.

	Derivatives (net)
	Three Months Ended September 30,						Nine Months Ended September 30,
(in millions)	2017			2016			2017			2016
Balance at beginning of period	$	51		$	29		$	16		$	7
Purchases, sales, issuances and settlements:
Purchases	—			—			52			29
Settlements	(11		)	(7		)	(27		)	(18		)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(12		)	(2		)	(13		)	2
Balance at end of period	$	28		$	20		$	28		$	20

Piedmont Natural Gas [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value Measurement Amounts For Assets And Liabilities

The following table provides recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	September 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 3			Total Fair Value			Level 1		Level 3
Other trading equity securities	$	1		$	1	$	—		$	4		$	4	$	—
Other trading debt securities	—			—		—			1			1		—
Derivative assets	2			2		—			3			3		—
Total assets	3			3		—			8			8		—
Derivative liabilities	(123		)	—		(123		)	(187		)	—		(187		)
Net (liabilities) assets	$	(120	)	$	3	$	(123	)	$	(179	)	$	8	$	(187	)

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

The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.

	Derivatives (net)
	Three Months Ended September 30,						Nine Months Ended September 30,
(in millions)	2017			2016			2017			2016
Balance at beginning of period	$	(145	)	$	(190	)	$	(187	)	$	(149	)
Total gains (losses) and settlements	22			(5		)	64			(46		)
Balance at end of period	$	(123	)	$	(195	)	$	(123	)	$	(195	)