Fair Value Measurements (Tables)

6 Months Ended

Jun. 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 9. See Note 10 for additional information related to investments by major security type for the Duke Energy Registrants.

	June 30, 2017
(in millions)	Total Fair Value			Level 1			Level 2			Level 3			Not categorized
NDTF equity securities	$	4,422		$	4,345		$	—		$	—		$	77
NDTF debt securities	2,170			593			1,577			—			—
Other trading and AFS equity securities	112			112			—			—			—
Other trading and AFS debt securities	245			63			182			—			—
Derivative assets	95			4			37			54			—
Total assets	7,044			5,117			1,796			54			77
Derivative liabilities	(227		)	(1		)	(81		)	(145		)	—
Net assets (liabilities)	$	6,817		$	5,116		$	1,715		$	(91	)	$	77

	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 June 30, 2017									Three Months Ended June 30, 2016
(in millions)	Investments			Derivatives (net)			Total			Investments		Derivatives (net)			Total
Balance at beginning of period	$	5		$	(135	)	$	(130	)	$	4	$	2		$	6
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		)	—		—			—
Settlements	—			(9		)	(9		)	—		(6		)	(6		)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	—			(2		)	(2		)	—		4			4
Balance at end of period	$	—		$	(91	)	$	(91	)	$	4	$	34		$	38

	Six Months Ended June 30, 2017									Six Months Ended June 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	—			(18		)	(18		)	—			(13		)	(13		)
Total gains included on the Condensed Consolidated Balance Sheet	—			38			38			—			3			3
Balance at end of period	$	—		$	(91	)	$	(91	)	$	4		$	34		$	38

Quantitative Information Table - Level 3

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

	June 30, 2017
	Fair Value
Investment Type	(in millions)			Valuation Technique	Unobservable Input	Range
Duke Energy Ohio
Financial Transmission Rights (FTRs)	$	3		RTO auction pricing	FTR price – per megawatt-hour (MWh)	$	(5.24	)	-	$	1.82
Duke Energy Indiana
FTRs	51			RTO auction pricing	FTR price – per MWh	(1.65		)	-	6.66
Piedmont
Natural gas contracts	(145		)	Discounted cash flow	Forward natural gas curves – price per million British thermal unit (MMBtu)	2.21			-	3.78
Duke Energy
Total Level 3 derivatives	$	(91	)

	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.

	June 30, 2017				December 31, 2016
(in millions)	Book Value		Fair Value		Book Value		Fair Value
Duke Energy	$	49,515	$	51,947	$	47,895	$	49,161
Duke Energy Carolinas	9,524		10,657		9,603		10,494
Progress Energy	18,145		20,101		17,541		19,107
Duke Energy Progress	6,760		7,266		7,011		7,357
Duke Energy Florida	6,979		7,753		6,125		6,728
Duke Energy Ohio	1,977		2,155		1,884		2,020
Duke Energy Indiana	3,784		4,379		3,786		4,260
Piedmont	1,946		2,107		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.

	June 30, 2017
(in millions)	Total Fair Value			Level 1		Level 2			Level 3		Not categorized
NDTF equity securities	$	2,441		$	2,364	$	—		$	—	$	77
NDTF debt securities	1,049			141		908			—		—
Derivative assets	8			—		8			—		—
Total assets	3,498			2,505		916			—		77
Derivative liabilities	(26		)	—		(26		)	—		—
Net assets	$	3,472		$	2,505	$	890		$	—	$	77

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

	June 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	1,981		$	1,981	$	—		$	1,861		$	1,861	$	—
NDTF debt securities	1,121			452		669			1,065			454		611
Other AFS debt securities	59			12		47			65			21		44
Derivative assets	15			—		15			85			—		85
Total assets	3,176			2,445		731			3,076			2,336		740
Derivative liabilities	(35		)	—		(35		)	(25		)	—		(25		)
Net assets	$	3,141		$	2,445	$	696		$	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 tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	June 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	1,607		$	1,607	$	—		$	1,505		$	1,505	$	—
NDTF debt securities and other	772			226		546			708			207		501
Other AFS debt securities and other	1			1		—			1			1		—
Derivative assets	8			—		8			46			—		46
Total assets	2,388			1,834		554			2,260			1,713		547
Derivative liabilities	(8		)	—		(8		)	(7		)	—		(7		)
Net assets	$	2,380		$	1,834	$	546		$	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 tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	June 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 1		Level 2			Total Fair Value			Level 1		Level 2
NDTF equity securities	$	374		$	374	$	—		$	356		$	356	$	—
NDTF debt securities and other	349			226		123			357			247		110
Other AFS debt securities and other	48			1		47			48			4		44
Derivative assets	6			—		6			39			—		39
Total assets	777			601		176			800			607		193
Derivative liabilities	(20		)	—		(20		)	(12		)	—		(12		)
Net assets	$	757		$	601	$	156		$	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 tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets.

	June 30, 2017								December 31, 2016
(in millions)	Total Fair Value			Level 2			Level 3		Total Fair Value			Level 2			Level 3
Derivative assets	$	3		$	—		$	3	$	5		$	—		$	5
Derivative liabilities	(5		)	(5		)	—		(6		)	(6		)	—
Net (liabilities) assets	$	(2	)	$	(5	)	$	3	$	(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 June 30,					Six Months Ended June 30,
(in millions)	2017			2016		2017			2016
Balance at beginning of period	$	1		$	—	$	5		$	3
Purchases, sales, issuances and settlements:
Purchases	3			5		3			5
Settlements	(1		)	—		(2		)	(2		)
Total losses included on the Condensed Consolidated Balance Sheet	—			—		(3		)	(1		)
Balance at end of period	$	3		$	5	$	3		$	5

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

	June 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	$	87	$	87	$	—	$	—	$	79		$	79		$	—	$	—
Other AFS debt securities and other	31		—		31		—		31			—			31		—
Derivative assets	54		3		—		51		16			—			—		16
Total assets	172		90		31		51		126			79			31		16
Derivative liabilities	—		—		—		—		(2		)	(2		)	—		—
Net assets	$	172	$	90	$	31	$	51	$	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 June 30,						Six Months Ended June 30,
(in millions)	2017			2016			2017			2016
Balance at beginning of period	$	9		$	2		$	16		$	7
Purchases, sales, issuances and settlements:
Purchases	52			29			52			29
Settlements	(9		)	(6		)	(16		)	(11		)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(1		)	4			(1		)	4
Balance at end of period	$	51		$	29		$	51		$	29

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

	June 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	2			2		—			$	4		$	4	$	—
Other trading debt securities	—			—		—			1			1		—
Derivative assets	2			2		—			3			3		—
Total assets	4			4		—			8			8		—
Derivative liabilities	(145		)	—		(145		)	(187		)	—		(187		)
Net (liabilities) assets	$	(141	)	$	4	$	(145	)	$	(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 June 30,						Six Months Ended June 30,
(in millions)	2017			2016			2017			2016
Balance at beginning of period	$	(145	)	$	(126	)	$	(187	)	$	(149	)
Total (losses) gains and settlements	—			(64		)	42			(41		)
Balance at end of period	$	(145	)	$	(190	)	$	(145	)	$	(190	)