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Investments in Debt and Equity Securities (Tables)

9 Months Ended

Sep. 30, 2018

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	75	$	—	$	—	$	115
Equity securities	3,117		48		5,272		2,805		27		4,914
Corporate debt securities	5		10		595		17		2		570
Municipal bonds	—		7		346		4		3		344
U.S. government bonds	5		25		974		11		7		1,027
Other debt securities	—		3		141		—		1		118
Total NDTF Investments	$	3,127	$	93	$	7,403	$	2,837	$	40	$	7,088
Other Investments
Cash and cash equivalents	$	—	$	—	$	21	$	—	$	—	$	15
Equity securities	51		—		115		59		—		123
Corporate debt securities	—		1		64		1		—		57
Municipal bonds	1		1		85		2		1		83
U.S. government bonds	—		1		59		—		—		41
Other debt securities	—		1		43		—		1		44
Total Other Investments	$	52	$	4	$	387	$	62	$	2	$	363
Total Investments	$	3,179	$	97	$	7,790	$	2,899	$	42	$	7,451


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	75	$	—	$	—	$	115
Equity securities	3,117		48		5,272		2,805		27		4,914
Corporate debt securities	5		10		595		17		2		570
Municipal bonds	—		7		346		4		3		344
U.S. government bonds	5		25		974		11		7		1,027
Other debt securities	—		3		141		—		1		118
Total NDTF Investments	$	3,127	$	93	$	7,403	$	2,837	$	40	$	7,088
Other Investments
Cash and cash equivalents	$	—	$	—	$	21	$	—	$	—	$	15
Equity securities	51		—		115		59		—		123
Corporate debt securities	—		1		64		1		—		57
Municipal bonds	1		1		85		2		1		83
U.S. government bonds	—		1		59		—		—		41
Other debt securities	—		1		43		—		1		44
Total Other Investments	$	52	$	4	$	387	$	62	$	2	$	363
Total Investments	$	3,179	$	97	$	7,790	$	2,899	$	42	$	7,451


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	75	$	—	$	—	$	115
Equity securities	3,117		48		5,272		2,805		27		4,914
Corporate debt securities	5		10		595		17		2		570
Municipal bonds	—		7		346		4		3		344
U.S. government bonds	5		25		974		11		7		1,027
Other debt securities	—		3		141		—		1		118
Total NDTF Investments	$	3,127	$	93	$	7,403	$	2,837	$	40	$	7,088
Other Investments
Cash and cash equivalents	$	—	$	—	$	21	$	—	$	—	$	15
Equity securities	51		—		115		59		—		123
Corporate debt securities	—		1		64		1		—		57
Municipal bonds	1		1		85		2		1		83
U.S. government bonds	—		1		59		—		—		41
Other debt securities	—		1		43		—		1		44
Total Other Investments	$	52	$	4	$	387	$	62	$	2	$	363
Total Investments	$	3,179	$	97	$	7,790	$	2,899	$	42	$	7,451


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	100
Due after one through five years	492
Due after five through 10 years	561
Due after 10 years	1,154
Total	$	2,307

Schedule of Realized Gain (Loss)

Realized gains and losses, which were determined on a specific identification basis, from sales of FV-NI and AFS securities for the three and nine months ended September 30, 2018, and from sales of AFS securities for the three and nine months ended September 30, 2017, were as follows.



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2018		September 30, 2018
FV-NI:
Realized gains	$	19	$	85
Realized losses	16		60
AFS:
Realized gains	4		14
Realized losses	7		32



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2017		September 30, 2017
Realized gains	$	37	$	170
Realized losses	25		124

Duke Energy Carolinas [Member]

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	32
Equity securities	1,692		29		2,890		1,531		12		2,692
Corporate debt securities	2		7		372		9		2		359
Municipal bonds	—		2		80		—		1		60
U.S. government bonds	1		14		439		3		4		503
Other debt securities	—		3		137		—		1		112
Total NDTF Investments	$	1,695	$	55	$	3,936	$	1,543	$	20	$	3,758


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	32
Equity securities	1,692		29		2,890		1,531		12		2,692
Corporate debt securities	2		7		372		9		2		359
Municipal bonds	—		2		80		—		1		60
U.S. government bonds	1		14		439		3		4		503
Other debt securities	—		3		137		—		1		112
Total NDTF Investments	$	1,695	$	55	$	3,936	$	1,543	$	20	$	3,758


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	32
Equity securities	1,692		29		2,890		1,531		12		2,692
Corporate debt securities	2		7		372		9		2		359
Municipal bonds	—		2		80		—		1		60
U.S. government bonds	1		14		439		3		4		503
Other debt securities	—		3		137		—		1		112
Total NDTF Investments	$	1,695	$	55	$	3,936	$	1,543	$	20	$	3,758


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	12
Due after one through five years	161
Due after five through 10 years	289
Due after 10 years	566
Total	$	1,028

Schedule of Realized Gain (Loss)



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2018		September 30, 2018
FV-NI:
Realized gains	$	11	$	47
Realized losses	8		30
AFS:
Realized gains	4		13
Realized losses	6		24



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2017		September 30, 2017
Realized gains	$	20	$	110
Realized losses	13		76

Progress Energy [Member]

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	57	$	—	$	—	$	83
Equity securities	1,425		19		2,382		1,274		15		2,222
Corporate debt securities	3		3		223		8		—		211
Municipal bonds	—		5		266		4		2		284
U.S. government bonds	4		11		535		8		3		524
Other debt securities	—		—		4		—		—		6
Total NDTF Investments	$	1,432	$	38	$	3,467	$	1,294	$	20	$	3,330
Other Investments
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	12
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	66	$	2	$	—	$	59
Total Investments	$	1,433	$	38	$	3,533	$	1,296	$	20	$	3,389


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	57	$	—	$	—	$	83
Equity securities	1,425		19		2,382		1,274		15		2,222
Corporate debt securities	3		3		223		8		—		211
Municipal bonds	—		5		266		4		2		284
U.S. government bonds	4		11		535		8		3		524
Other debt securities	—		—		4		—		—		6
Total NDTF Investments	$	1,432	$	38	$	3,467	$	1,294	$	20	$	3,330
Other Investments
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	12
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	66	$	2	$	—	$	59
Total Investments	$	1,433	$	38	$	3,533	$	1,296	$	20	$	3,389


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	57	$	—	$	—	$	83
Equity securities	1,425		19		2,382		1,274		15		2,222
Corporate debt securities	3		3		223		8		—		211
Municipal bonds	—		5		266		4		2		284
U.S. government bonds	4		11		535		8		3		524
Other debt securities	—		—		4		—		—		6
Total NDTF Investments	$	1,432	$	38	$	3,467	$	1,294	$	20	$	3,330
Other Investments
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	12
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	66	$	2	$	—	$	59
Total Investments	$	1,433	$	38	$	3,533	$	1,296	$	20	$	3,389


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	83
Due after one through five years	268
Due after five through 10 years	217
Due after 10 years	508
Total	$	1,076

Schedule of Realized Gain (Loss)



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2018		September 30, 2018
FV-NI:
Realized gains	$	8	$	38
Realized losses	8		30
AFS:
Realized gains	—		1
Realized losses	1		8



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2017		September 30, 2017
Realized gains	$	16	$	58
Realized losses	12		47

Duke Energy Progress [Member]

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	42	$	—	$	—	$	50
Equity securities	1,101		14		1,913		980		12		1,795
Corporate debt securities	2		2		162		6		—		149
Municipal bonds	—		5		265		4		2		283
U.S. government bonds	3		8		352		5		2		310
Other debt securities	—		—		2		—		—		4
Total NDTF Investments	$	1,106	$	29	$	2,736	$	995	$	16	$	2,591
Other Investments
Cash and cash equivalents	$	—	$	—	$	8	$	—	$	—	$	1
Total Other Investments	$	—	$	—	$	8	$	—	$	—	$	1
Total Investments	$	1,106	$	29	$	2,744	$	995	$	16	$	2,592


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	42	$	—	$	—	$	50
Equity securities	1,101		14		1,913		980		12		1,795
Corporate debt securities	2		2		162		6		—		149
Municipal bonds	—		5		265		4		2		283
U.S. government bonds	3		8		352		5		2		310
Other debt securities	—		—		2		—		—		4
Total NDTF Investments	$	1,106	$	29	$	2,736	$	995	$	16	$	2,591
Other Investments
Cash and cash equivalents	$	—	$	—	$	8	$	—	$	—	$	1
Total Other Investments	$	—	$	—	$	8	$	—	$	—	$	1
Total Investments	$	1,106	$	29	$	2,744	$	995	$	16	$	2,592


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	42	$	—	$	—	$	50
Equity securities	1,101		14		1,913		980		12		1,795
Corporate debt securities	2		2		162		6		—		149
Municipal bonds	—		5		265		4		2		283
U.S. government bonds	3		8		352		5		2		310
Other debt securities	—		—		2		—		—		4
Total NDTF Investments	$	1,106	$	29	$	2,736	$	995	$	16	$	2,591
Other Investments
Cash and cash equivalents	$	—	$	—	$	8	$	—	$	—	$	1
Total Other Investments	$	—	$	—	$	8	$	—	$	—	$	1
Total Investments	$	1,106	$	29	$	2,744	$	995	$	16	$	2,592


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	40
Due after one through five years	200
Due after five through 10 years	156
Due after 10 years	385
Total	$	781

Schedule of Realized Gain (Loss)



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2018		September 30, 2018
FV-NI:
Realized gains	$	7	$	32
Realized losses	7		27
AFS:
Realized gains	—		1
Realized losses	1		6



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2017		September 30, 2017
Realized gains	$	14	$	49
Realized losses	11		41

Duke Energy Florida [Member]

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	15	$	—	$	—	$	33
Equity securities	324		5		469		294		3		427
Corporate debt securities	1		1		61		2		—		62
Municipal bonds	—		—		1		—		—		1
U.S. government bonds	1		3		183		3		1		214
Other debt securities	—		—		2		—		—		2
Total NDTF Investments^(b)	$	326	$	9	$	731	$	299	$	4	$	739
Other Investments
Cash and cash equivalents	$	—	$	—	$	—	$	—	$	—	$	1
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	48	$	2	$	—	$	48
Total Investments	$	327	$	9	$	779	$	301	$	4	$	787


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.


(b)	During the nine months ended September 30, 2018, Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	15	$	—	$	—	$	33
Equity securities	324		5		469		294		3		427
Corporate debt securities	1		1		61		2		—		62
Municipal bonds	—		—		1		—		—		1
U.S. government bonds	1		3		183		3		1		214
Other debt securities	—		—		2		—		—		2
Total NDTF Investments^(b)	$	326	$	9	$	731	$	299	$	4	$	739
Other Investments
Cash and cash equivalents	$	—	$	—	$	—	$	—	$	—	$	1
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	48	$	2	$	—	$	48
Total Investments	$	327	$	9	$	779	$	301	$	4	$	787


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.


(b)	During the nine months ended September 30, 2018, Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are classified as FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
NDTF
Cash and cash equivalents	$	—	$	—	$	15	$	—	$	—	$	33
Equity securities	324		5		469		294		3		427
Corporate debt securities	1		1		61		2		—		62
Municipal bonds	—		—		1		—		—		1
U.S. government bonds	1		3		183		3		1		214
Other debt securities	—		—		2		—		—		2
Total NDTF Investments^(b)	$	326	$	9	$	731	$	299	$	4	$	739
Other Investments
Cash and cash equivalents	$	—	$	—	$	—	$	—	$	—	$	1
Municipal bonds	1		—		48		2		—		47
Total Other Investments	$	1	$	—	$	48	$	2	$	—	$	48
Total Investments	$	327	$	9	$	779	$	301	$	4	$	787


(a)	Where regulatory accounting is applied, realized and unrealized gains and losses are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.


(b)	During the nine months ended September 30, 2018, Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	43
Due after one through five years	68
Due after five through 10 years	61
Due after 10 years	123
Total	$	295

Schedule of Realized Gain (Loss)



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2018		September 30, 2018
FV-NI:
Realized gains	$	1	$	6
Realized losses	1		3
AFS:
Realized gains	—		—
Realized losses	—		2



	Three Months Ended		Nine Months Ended
(in millions)	September 30, 2017		September 30, 2017
Realized gains	$	2	$	9
Realized losses	1		6

Duke Energy Indiana [Member]

Debt Securities, Available-for-sale [Line Items]

Debt Securities, Trading, and Equity Securities, FV-NI

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
Investments
Equity securities	$	40	$	—	$	78	$	49	$	—	$	97
Corporate debt securities	—		—		8		—		—		3
Municipal bonds	—		1		32		—		1		28
Total Investments	$	40	$	1	$	118	$	49	$	1	$	128


(a)	Realized and unrealized gains and losses where regulatory accounting is applied are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Debt Securities, Available-for-sale

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
Investments
Equity securities	$	40	$	—	$	78	$	49	$	—	$	97
Corporate debt securities	—		—		8		—		—		3
Municipal bonds	—		1		32		—		1		28
Total Investments	$	40	$	1	$	118	$	49	$	1	$	128


(a)	Realized and unrealized gains and losses where regulatory accounting is applied are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Available-for-sale Securities

The following table presents the estimated fair value of investments in debt and equity securities; equity investments are measured at FV-NI and debt investments are classified as AFS.



	September 30, 2018^(a)						December 31, 2017
	Gross		Gross				Gross		Gross
	Unrealized		Unrealized		Estimated		Unrealized		Unrealized		Estimated
	Holding		Holding		Fair		Holding		Holding		Fair
(in millions)	Gains		Losses		Value		Gains		Losses		Value
Investments
Equity securities	$	40	$	—	$	78	$	49	$	—	$	97
Corporate debt securities	—		—		8		—		—		3
Municipal bonds	—		1		32		—		1		28
Total Investments	$	40	$	1	$	118	$	49	$	1	$	128


(a)	Realized and unrealized gains and losses where regulatory accounting is applied are deferred as regulatory assets or liabilities, and there is no impact to net income or other comprehensive income until the gain or loss is amortized or collected.

Investments Classified by Contractual Maturity Date

The table below summarizes the maturity date for debt securities.



(in millions)	September 30, 2018
Due in one year or less	$	2
Due after one through five years	20
Due after five through 10 years	5
Due after 10 years	13
Total	$	40