Debt and Credit Facilities (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Debt

The following table shows the significant components of Current maturities of Long-Term Debt on the Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings.

(in millions)	Maturity Date	Interest Rate			December 31, 2017
Unsecured Debt
Duke Energy (Parent)	June 2018	6.250	%		$	250
Duke Energy (Parent)	June 2018	2.100	%		500
Piedmont	December 2018	2.286	%	(b)	250
First Mortgage Bonds
Duke Energy Carolinas	January 2018	5.250	%		400
Duke Energy Carolinas	April 2018	5.100	%		300
Duke Energy Florida	June 2018	5.650	%		500
Duke Energy Carolinas	November 2018	7.000	%		500
Other(a)					544
Current maturities of long-term debt					$	3,244

(a) Includes capital lease obligations, amortizing debt and small bullet maturities.

(b) Debt has a floating interest rate.

The following tables summarize outstanding debt.

	December 31, 2017
	Weighted
	Average					Duke						Duke			Duke			Duke			Duke
	Interest		Duke			Energy			Progress			Energy			Energy			Energy			Energy
(in millions)	Rate		Energy			Carolinas			Energy			Progress			Florida			Ohio			Indiana			Piedmont
Unsecured debt, maturing 2018-2073	4.17	%	$	20,409		$	1,150		$	3,950		$	—		$	550		$	900		$	411		$	2,050
Secured debt, maturing 2018-2037	3.15	%	4,458			450			1,757			300			1,457			—			—			—
First mortgage bonds, maturing 2018-2047(a)	4.51	%	23,529			7,959			11,801			6,776			5,025			1,100			2,669			—
Capital leases, maturing 2018-2051(b)	4.55	%	1,000			61			269			139			129			5			11			—
Tax-exempt bonds, maturing 2019-2041(c)	3.23	%	941			243			48			48			—			77			572			—
Notes payable and commercial paper(d)	1.57	%	2,788			—			—			—			—			—			—			—
Money pool/intercompany borrowings			—			404			955			390			—			54			311			364
Fair value hedge carrying value adjustment			6			6			—			—			—			—			—			—
Unamortized debt discount and premium, net(e)			1,582			(19		)	(30		)	(16		)	(10		)	(33		)	(9		)	(1		)
Unamortized debt issuance costs(f)			(271		)	(47		)	(108		)	(40		)	(56		)	(7		)	(21		)	(12		)
Total debt	4.09	%	$	54,442		$	10,207		$	18,642		$	7,597		$	7,095		$	2,096		$	3,944		$	2,401
Short-term notes payable and commercial paper			(2,163		)	—			—			—			—			—			—			—
Short-term money pool/intercompany borrowings			—			(104		)	(805		)	(240		)	—			(29		)	(161		)	(364		)
Current maturities of long-term debt(g)			(3,244		)	(1,205		)	(771		)	(3		)	(768		)	(3		)	(3		)	(250		)
Total long-term debt(g)			$	49,035		$	8,898		$	17,066		$	7,354		$	6,327		$	2,064		$	3,780		$	1,787

(a) Substantially all electric utility property is mortgaged under mortgage bond indentures.

(b) Duke Energy includes $81 million and $603 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP.

(c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit.

(d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy's commercial paper program was 14 days.

(e) Duke Energy includes $1,509 million and $176 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively.

(f) Duke Energy includes $47 million in purchase accounting adjustments primarily related to the merger with Progress Energy.

(g) Refer to Note 17 for additional information on amounts from consolidated VIEs.

	December 31, 2016
	Weighted
	Average					Duke						Duke			Duke			Duke			Duke
	Interest		Duke			Energy			Progress			Energy			Energy			Energy			Energy
(in millions)	Rate		Energy			Carolinas			Energy			Progress			Florida			Ohio			Indiana			Piedmont
Unsecured debt, maturing 2017-2073	4.30	%	$	17,812		$	1,150		$	3,551		$	—		$	150		$	810		$	415		$	1,835
Secured debt, maturing 2017-2037	2.60	%	3,909			425			1,819			300			1,519			—			—			—
First mortgage bonds, maturing 2017-2046(a)	4.61	%	21,879			7,410			10,800			6,425			4,375			1,000			2,669			—
Capital leases, maturing 2018-2051(b)	4.48	%	1,100			22			285			142			143			7			11			—
Tax-exempt bonds, maturing 2017-2041(c)	2.84	%	1,053			355			48			48			—			77			572			—
Notes payable and commercial paper(d)	1.01	%	3,112			—			—			—			—			—			—			—
Money pool/intercompany borrowings(e)			—			300			1,902			150			297			41			150			—
Fair value hedge carrying value adjustment			6			6			—			—			—			—			—			—
Unamortized debt discount and premium, net(f)			1,753			(20		)	(31		)	(16		)	(10		)	(28		)	(9		)	(1		)
Unamortized debt issuance costs(g)			(242		)	(45		)	(104		)	(38		)	(52		)	(7		)	(22		)	(13		)
Total debt	4.07	%	$	50,382		$	9,603		$	18,270		$	7,011		$	6,422		$	1,900		$	3,786		$	1,821
Short-term notes payable and commercial paper			(2,487		)	—			—			—			—			—			—			—
Short-term money pool/intercompany borrowings			—			—			(729		)	—			(297		)	(16		)	—			—
Current maturities of long-term debt(h)			(2,319		)	(116		)	(778		)	(452		)	(326		)	(1		)	(3		)	(35		)
Total long-term debt(h)			$	45,576		$	9,487		$	16,763		$	6,559		$	5,799		$	1,883		$	3,783		$	1,786

(a) Substantially all electric utility property is mortgaged under mortgage bond indentures.

(b) Duke Energy includes $98 million and $670 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP.

(c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit.

(d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy and Piedmont's commercial paper programs were 14 days and eight days, respectively.

(e) Progress Energy amount includes a $1 billion intercompany loan related to the sale of the International Disposal Group. See Note 2 for further discussion of the sale.

(f) Duke Energy includes $1,653 million and $197 million purchase accounting adjustments related to the mergers with Progress Energy and Piedmont, respectively.

(g) Duke Energy includes $53 million in purchase accounting adjustments primarily related to the merger with Progress Energy.

(h) Refer to Note 17 for additional information on amounts from consolidated VIEs.

The following tables show short-term obligations classified as long-term debt.

	December 31, 2017
			Duke		Duke		Duke		Duke
	Duke		Energy		Energy		Energy		Energy
(in millions)	Energy		Carolinas		Progress		Ohio		Indiana
Tax-exempt bonds	$	312	$	—	$	—	$	27	$	285
Commercial paper(a)	625		300		150		25		150
Total	$	937	$	300	$	150	$	52	$	435

	December 31, 2016
			Duke		Duke		Duke		Duke
	Duke		Energy		Energy		Energy		Energy
(in millions)	Energy		Carolinas		Progress		Ohio		Indiana
Tax-exempt bonds	$	347	$	35	$	—	$	27	$	285
Commercial paper(a)	625		300		150		25		150
Total	$	972	$	335	$	150	$	52	$	435

(a) Progress Energy amounts are equal to Duke Energy Progress amounts.

Schedule of Maturities of Long-term Debt

The following table shows the annual maturities of long-term debt for the next five years and thereafter. Amounts presented exclude short-term notes payable and commercial paper and money pool borrowings for the Subsidiary Registrants.

	December 31, 2017
			Duke				Duke		Duke		Duke		Duke
	Duke		Energy		Progress		Energy		Energy		Energy		Energy
(in millions)	Energy(a)		Carolinas		Energy		Progress		Florida		Ohio		Indiana		Piedmont
2018	$	3,244	$	1,205	$	771	$	3	$	768	$	3	$	3	$	250
2019	3,563		6		2,191		903		490		548		61		—
2020	3,699		906		871		304		568		—		502		—
2021	3,760		502		1,472		602		371		48		69		159
2022	3,010		302		1,176		653		74		23		243		—
Thereafter	33,271		7,182		11,356		4,892		4,824		1,445		2,905		1,628
Total long-term debt, including current maturities	$	50,547	$	10,103	$	17,837	$	7,357	$	7,095	$	2,067	$	3,783	$	2,037

(a) Excludes $1,732 million in purchase accounting adjustments related to the Progress Energy merger and the Piedmont acquisition.

Schedule of Long-term Debt Instruments

The following tables summarize significant debt issuances (in millions).

						Year Ended December 31, 2017
								Duke		Duke		Duke		Duke		Duke
	Maturity		Interest			Duke		Energy		Energy		Energy		Energy		Energy
Issuance Date	Date		Rate			Energy		(Parent)		Carolinas		Progress		Florida		Ohio
Unsecured Debt
April 2017(a)	April 2025		3.364	%		$	420	$	420	$	—	$	—	$	—	$	—
June 2017(b)	June 2020		2.100	%		330		330		—		—		—		—
August 2017(c)	August 2022		2.400	%		500		500		—		—		—		—
August 2017(c)	August 2027		3.150	%		750		750		—		—		—		—
August 2017(c)	August 2047		3.950	%		500		500		—		—		—		—
December 2017(d)	December 2019	(k)	2.100	%		400		—		—		—		400		—
Secured Debt
February 2017(e)	June 2034		4.120	%		587		—		—		—		—		—
August 2017(f)	December 2036		4.110	%		233		—		—		—		—		—
First Mortgage Bonds
January 2017(g)	January 2020		1.850	%		250		—		—		—		250		—
January 2017(g)	January 2027		3.200	%		650		—		—		—		650		—
March 2017(h)	June 2046		3.700	%		100		—		—		—		—		100
September 2017(i)	September 2020		1.500	%	(l)	300		—		—		300		—		—
September 2017(i)	September 2047		3.600	%		500		—		—		500		—		—
November 2017(j)	December 2047		3.700	%		550		—		550		—		—		—
Total issuances						$	6,070	$	2,500	$	550	$	800	$	1,300	$	100

(a) Proceeds were used to refinance $400 million of unsecured debt at maturity and to repay a portion of outstanding commercial paper.

(b) Debt issued to repay a portion of outstanding commercial paper.

(c) Debt issued to repay at maturity $700 million of unsecured debt, to repay outstanding commercial paper and for general corporate purposes.

(d) Debt issued to fund storm restoration costs related to Hurricane Irma and for general corporate purposes.

(e) Portfolio financing of four Texas and Oklahoma wind facilities. Duke Energy pledged substantially all of the assets of these wind facilities and is nonrecourse to Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures.

(f) Portfolio financing of eight solar facilities located in California, Colorado and New Mexico. Duke Energy pledged substantially all of the assets of these solar facilities and is nonrecourse to Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures.

(g) Debt issued to fund capital expenditures for ongoing construction and capital maintenance, to repay a $250 million aggregate principal amount of bonds at maturity and for general corporate purposes.

(h) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes.

(i) Debt issued to repay at maturity a $200 million aggregate principal amount of bonds at maturity, pay down intercompany short-term debt and for general corporate purposes, including capital expenditures.

(j) Debt issued to refinance $400 million aggregate principal amount of bonds due January 2018, pay down intercompany short-term debt and for general corporate purposes.

(k) Principal balance will be repaid in equal quarterly installments beginning in March 2018.

(l) Debt issuance has a floating interest rate.

					Year Ended December 31, 2016
							Duke		Duke		Duke		Duke		Duke		Duke
	Maturity	Interest			Duke		Energy		Energy		Energy		Energy		Energy		Energy
Issuance Date	Date	Rate			Energy		(Parent)		Carolinas		Progress		Florida		Ohio		Indiana
Unsecured Debt
April 2016(a)	April 2023	2.875	%		$	350	$	350	$	—	$	—	$	—	$	—	$	—
August 2016(b)	September 2021	1.800	%		750		750		—		—		—		—		—
August 2016(b)	September 2026	2.650	%		1,500		1,500		—		—		—		—		—
August 2016(b)	September 2046	3.750	%		1,500		1,500		—		—		—		—		—
Secured Debt
June 2016(c)	March 2020	1.196	%		183		—		—		—		183		—		—
June 2016(c)	September 2022	1.731	%		150		—		—		—		150		—		—
June 2016(c)	September 2029	2.538	%		436		—		—		—		436		—		—
June 2016(c)	March 2033	2.858	%		250		—		—		—		250		—		—
June 2016(c)	September 2036	3.112	%		275		—		—		—		275		—		—
August 2016(d)	June 2034	2.747	%	(i)	228		—		—		—		—		—		—
August 2016(d)	June 2020	2.747	%	(i)	105		—		—		—		—		—		—
First Mortgage Bonds
March 2016(e)	March 2023	2.500	%		500		—		500		—		—		—		—
March 2016(e)	March 2046	3.875	%		500		—		500		—		—		—		—
May 2016(f)	May 2046	3.750	%		500		—		—		—		—		—		500
June 2016(e)	June 2046	3.700	%		250		—		—		—		—		250		—
September 2016(g)	October 2046	3.400	%		600		—		—		—		600		—		—
September 2016(e)	October 2046	3.700	%		450		—		—		450		—		—		—
November 2016(h)	December 2046	2.950	%		600		—		600		—		—		—		—
Total issuances					$	9,127	$	4,100	$	1,600	$	450	$	1,894	$	250	$	500

(a) Proceeds were used to pay down outstanding commercial paper and for general corporate purposes.

(b) Proceeds were used to finance a portion of the Piedmont acquisition. The $4.9 billion Bridge Facility was terminated following the issuance of this debt. See Note 2 for additional information on the Piedmont acquisition.

(c) DEFPF issued nuclear-asset recovery bonds and used the proceeds to acquire nuclear-asset recovery property from its parent, Duke Energy Florida. The nuclear-asset recovery bonds are payable only from and secured by the nuclear asset-recovery property. DEFPF is consolidated for financial reporting purposes; however, the nuclear asset-recovery bonds do not constitute a debt, liability or other legal obligation of, or interest in, Duke Energy Florida or any of its affiliates other than DEFPF. The assets of DEFPF, including the nuclear-asset recovery property, are not available to pay creditors of Duke Energy Florida or any of its affiliates. Duke Energy Florida used the proceeds from the sale to repay short-term borrowings under the intercompany money pool borrowing arrangement and make an equity distribution of $649 million to the ultimate parent, Duke Energy (Parent), which repaid short-term borrowings. The nuclear-asset recovery bonds are sequential pay amortizing bonds. The maturity date above represents the scheduled final maturity date for the bonds. See Notes 4 and 17 for additional information.

(d) Emerald State Solar, LLC, an indirect wholly owned subsidiary of Duke Energy entered into portfolio financing of approximately 22 North Carolina solar facilities. Tranche A of $228 million is secured by substantially all of the assets of the solar facilities and is nonrecourse to Duke Energy. Tranche B of $105 million is secured by an Equity Contribution Agreement with Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures related to the Emerald State Solar, LLC portfolio. The initial interest rate on the loans was six months London Interbank Offered Rate (LIBOR) plus an applicable margin of 1.75 percent plus a 0.125 percent increase every three years thereafter. In connection with this debt issuance, Emerald State Solar, LLC entered into two interest rate swaps to convert the substantial majority of the loan interest payments from variable rates to fixed rates of approximately 1.81 percent for Tranche A and 1.38 percent for Tranche B, plus the applicable margin. See Note 14 for further information on the notional amounts of the interest rate swaps.

(e) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes.

(f) Proceeds were used to repay $325 million of unsecured debt due June 2016, $150 million of first mortgage bonds due July 2016 and for general corporate purposes.

(g) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance, to repay short-term borrowings under the intercompany money pool borrowing arrangement and for general corporate purposes.

(h) Proceeds were used to repay at maturity $350 million aggregate principal amount of certain bonds due December 2016, as well as to fund capital expenditures for ongoing construction and capital maintenance and for general corporate purposes.

(i) Debt issuance has a floating interest rate.

Schedule Of Line Of Credit Facilities

	December 31, 2017
				Duke			Duke			Duke			Duke			Duke			Duke
	Duke			Energy			Energy			Energy			Energy			Energy			Energy
(in millions)	Energy			(Parent)			Carolinas			Progress			Florida			Ohio			Indiana			Piedmont
Facility size(a)	$	8,000		$	2,850		$	1,350		$	1,250		$	800		$	450		$	600		$	700
Reduction to backstop issuances
Commercial paper(b)	(1,799		)	(561		)	(371		)	(314		)	—			(45		)	(260		)	(248		)
Outstanding letters of credit	(63		)	(54		)	(4		)	(2		)	(1		)	—			—			(2		)
Tax-exempt bonds	(81		)	—			—			—			—			—			(81		)	—
Coal ash set-aside	(500		)	—			(250		)	(250		)	—			—			—			—
Available capacity	$	5,557		$	2,235		$	725		$	684		$	799		$	405		$	259		$	450

(a) Represents the sublimit of each borrower.

(b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Consolidated Balance Sheets.