Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Schedule of Current and Noncurrent Assets and Liabilities

The following table provides a description of amounts included in Other within Current Assets or Current Liabilities that exceed 5% of total Current Assets or Current Liabilities on the Duke Energy Registrants' Consolidated Balance Sheets at either December 31, 2020, or 2019.

		December 31,
(in millions)	Location	2020		2019
Duke Energy
Other accrued liabilities	Current Liabilities	$	1,455	$	604
Accrued compensation	Current Liabilities	662		862
Duke Energy Carolinas
Accrued compensation	Current Liabilities	$	213	$	271
Other accrued liabilities	Current Liabilities	178		147
Progress Energy
Customer deposits	Current Liabilities	$	347	$	354
Duke Energy Florida
Customer deposits	Current Liabilities	$	203	$	209
Duke Energy Ohio
Gas Storage	Current Assets	$	21	$	—
Duke Energy Indiana
Income taxes receivable	Current Assets	$	9	$	44

Noncontrolling Divestitures And Allocated Losses

The following table presents cash received for the sale of noncontrolling interest and allocated losses to noncontrolling interest for the years ended December 31, 2020, and 2019.

	December 31,
(in millions)	2020		2019
Noncontrolling Interest Capital Contributions
Cash received for the sale of noncontrolling interest to tax equity members	$	426	$	428
Cash received for the sale of noncontrolling interest to pro rata share members	—		415
Total Noncontrolling Interest Capital Contributions	$	426	$	843
Noncontrolling Interest Allocation of Income
Allocated losses to noncontrolling tax equity members utilizing the HLBV method	$	271	$	165
Allocated losses to noncontrolling members based on pro rata shares of ownership	24		12
Total Noncontrolling Interest Allocated Losses	$	295	$	177

Schedule of Cash and Cash Equivalents

The following table presents the components of cash, cash equivalents and restricted cash included in the Consolidated Balance Sheets.

	December 31, 2020						December 31, 2019
					Duke						Duke
	Duke		Progress		Energy		Duke		Progress		Energy
	Energy		Energy		Florida		Energy		Energy		Florida
Current Assets
Cash and cash equivalents	$	259	$	59	$	11	$	311	$	48	$	17
Other	194		39		39		222		39		39
Other Noncurrent Assets
Other	103		102		—		40		39		—
Total cash, cash equivalents and restricted cash	$	556	$	200	$	50	$	573	$	126	$	56

Components of Inventory

The components of inventory are presented in the tables below.

	December 31, 2020
			Duke				Duke		Duke		Duke		Duke
	Duke		Energy		Progress		Energy		Energy		Energy		Energy
(in millions)	Energy		Carolinas		Energy		Progress		Florida		Ohio		Indiana		Piedmont
Materials and supplies	$	2,312	$	785	$	999	$	673	$	325	$	78	$	307	$	12
Coal	561		186		193		131		63		16		165		—
Natural gas, oil and other	294		39		183		107		76		16		1		56
Total inventory	$	3,167	$	1,010	$	1,375	$	911	$	464	$	110	$	473	$	68

	December 31, 2019
			Duke				Duke		Duke		Duke		Duke
	Duke		Energy		Progress		Energy		Energy		Energy		Energy
(in millions)	Energy		Carolinas		Energy		Progress		Florida		Ohio		Indiana		Piedmont
Materials and supplies	$	2,297	$	768	$	1,038	$	686	$	351	$	79	$	318	$	5
Coal	586		187		186		138		48		15		198		—
Natural gas, oil and other	349		41		199		110		90		41		1		67
Total inventory	$	3,232	$	996	$	1,423	$	934	$	489	$	135	$	517	$	72

Schedule of Property, Plant and Equipment

The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows.

	Years Ended December 31,
	2020		2019		2018
Duke Energy	3.0	%	3.1	%	3.0	%
Duke Energy Carolinas	2.8	%	2.8	%	2.8	%
Progress Energy	3.2	%	3.1	%	2.9	%
Duke Energy Progress	3.1	%	3.1	%	2.9	%
Duke Energy Florida	3.3	%	3.1	%	3.0	%
Duke Energy Ohio	2.9	%	2.6	%	2.8	%
Duke Energy Indiana	3.5	%	3.3	%	3.3	%
Piedmont	2.3	%	2.4	%	2.5	%

The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants.

	December 31, 2020
	Average
	Remaining			Duke				Duke		Duke		Duke		Duke
	Useful Life	Duke		Energy		Progress		Energy		Energy		Energy		Energy
(in millions)	(Years)	Energy		Carolinas		Energy		Progress		Florida		Ohio		Indiana		Piedmont
Land		$	2,046	$	536	$	908	$	463	$	445	$	171	$	118	$	279
Plant – Regulated
Electric generation, distribution and transmission	39	117,107		44,059		50,785		31,375		19,410		6,255		16,008		—
Natural gas transmission and distribution	54	10,799		—		—		—		—		3,136		—		7,663
Other buildings and improvements	36	2,038		740		459		197		262		374		300		165
Plant – Nonregulated
Electric generation, distribution and transmission	27	5,444		—		—		—		—		—		—		—
Other buildings and improvements	10	519		—		—		—		—		—		—		—
Nuclear fuel		3,284		1,837		1,447		1,447		—		—		—		—
Equipment	15	2,608		620		759		498		261		385		238		122
Construction in process		6,645		1,645		2,013		709		1,304		407		409		581
Other	14	5,090		1,203		1,521		1,070		441		294		309		324
Total property, plant and equipment(a)(e)		155,580		50,640		57,892		35,759		22,123		11,022		17,382		9,134
Total accumulated depreciation – regulated(b)(c)		(46,216)		(17,453)		(18,368)		(12,801)		(5,560)		(3,013)		(5,661)		(1,749)
Total accumulated depreciation – nonregulated(d)(e)		(2,611)		—		—		—		—		—		—		—
Generation facilities to be retired, net		29		—		29		29		—		—		—		—
Total net property, plant and equipment		$	106,782	$	33,187	$	39,553	$	22,987	$	16,563	$	8,009	$	11,721	$	7,385

(a)    Includes finance leases of $832 million, $335 million, $416 million, $297 million, $119 million and $10 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $141 million, $24 million and $117 million, respectively, of accumulated amortization of finance leases.

(b)    Includes $1,832 million, $1,010 million, $822 million and $822 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively.

(c)    Includes accumulated amortization of finance leases of $12 million, $23 million and $3 million at Duke Energy, Duke Energy Carolinas and Duke Energy Indiana, respectively.

(d)    Includes accumulated amortization of finance leases of $23 million at Duke Energy.

(e)    Includes gross property, plant and equipment cost of consolidated VIEs of $6,394 million and accumulated depreciation of consolidated VIEs of $1,242 million at Duke Energy.

	December 31, 2019
	Average
	Remaining			Duke				Duke		Duke		Duke		Duke
	Useful Life	Duke		Energy		Progress		Energy		Energy		Energy		Energy
(in millions)	(Years)	Energy		Carolinas		Energy		Progress		Florida		Ohio		Indiana		Piedmont
Land		$	2,091	$	520	$	884	$	449	$	435	$	150	$	117	$	388
Plant – Regulated
Electric generation, distribution and transmission	39	111,739		42,723		48,142		30,018		18,124		5,838		15,032		—
Natural gas transmission and distribution	54	9,839		—		—		—		—		2,892		—		6,947
Other buildings and improvements	32	1,810		714		401		162		239		269		278		148
Plant – Nonregulated
Electric generation, distribution and transmission	28	5,103		—		—		—		—		—		—		—
Other buildings and improvements	9	488		—		—		—		—		—		—		—
Nuclear fuel		3,253		1,891		1,362		1,362		—		—		—		—
Equipment	13	2,313		546		665		452		213		319		205		128
Construction in process		6,102		1,389		2,149		1,114		1,035		504		381		531
Other	13	4,916		1,139		1,467		1,046		411		269		292		304
Total property, plant and equipment(a)(e)		147,654		48,922		55,070		34,603		20,457		10,241		16,305		8,446
Total accumulated depreciation – regulated(b)(c)		(43,419)		(16,525)		(17,159)		(11,915)		(5,236)		(2,843)		(5,233)		(1,681)
Total accumulated depreciation – nonregulated(d)(e)		(2,354)		—		—		—		—		—		—		—
Generation facilities to be retired, net		246		—		246		246		—		—		—		—
Total net property, plant and equipment		$	102,127	$	32,397	$	38,157	$	22,934	$	15,221	$	7,398	$	11,072	$	6,765

(a)    Includes finance leases of $952 million, $211 million, $443 million, $308 million, $135 million, and $10 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $143 million, $17 million and $126 million, respectively, of accumulated amortization of finance leases.

(b)    Includes $1,807 million, $1,082 million, $725 million and $725 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively.

(c)    Includes accumulated amortization of finance leases of $6 million, $13 million, and $3 million at Duke Energy, Duke Energy Carolinas and Duke Energy Indiana, respectively.

(d)    Includes accumulated amortization of finance leases of $20 million at Duke Energy.

(e)    Includes gross property, plant and equipment cost of consolidated VIEs of $5,747 million and accumulated depreciation of consolidated VIEs of $1,041 million at Duke Energy.

Schedule of Excise Taxes

Excise taxes accounted for on a gross basis within both Operating Revenues and Property and other taxes in the Consolidated Statements of Operations were as follows.

	Years Ended December 31,
(in millions)	2020		2019		2018
Duke Energy	$	415	$	421	$	405
Duke Energy Carolinas	43		39		35
Progress Energy	249		256		241
Duke Energy Progress	26		21		19
Duke Energy Florida	223		235		222
Duke Energy Ohio	96		101		105
Duke Energy Indiana	25		23		22
Piedmont	2		2		2

Summary of Effects of New Accounting Pronouncements

Duke Energy recorded an adjustment for the cumulative effect of a change in accounting principle due to the adoption of this standard on January 1, 2020, as shown in the table below:

	December 31, 2020
			Duke				Duke		Duke
	Duke		Energy		Progress		Energy		Energy
(in millions)	Energy		Carolinas		Energy		Progress		Florida		Piedmont
Total pretax impact to Retained Earnings	$	120	$	16	$	2	$	1	$	1	$	1