Consolidated Statements of Cash Flows - USD ($) $ in Millions	2 Months Ended	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net income		$ 454	$ 622	$ 703	$ 717	$ 2,644	$ 3,064	$ 2,170
Net Income Attributable to Parent		464	620	703	716	2,666	3,059	2,152
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						4,696	4,046	3,880
Equity component of AFUDC						(221)	(237)	(200)
Losses (Gains) on sales of other assets						88	(33)	477
Impairment charges						402	282	212
Deferred income taxes						1,079	1,433	900
Equity in (earnings) losses of unconsolidated affiliates						(83)	(119)	15
Accrued pension and other post-retirement benefit costs						61	8	21
Contributions to qualified pension plans						(141)	(19)	(155)
Payments for asset retirement obligations						(533)	(571)	(608)
Payment for the disposal of other assets						(105)
Other rate case adjustments						37
Provision for rate refunds						425
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions						22	18	34
Receivables						(345)	(83)	(372)
Inventory						156	268	272
Other current assets						(721)	(400)	(174)
Increase (decrease) in
Accounts payable						479	(204)	296
Taxes accrued						23	149	236
Other current liabilities						270	(482)	182
Other assets						(1,008)	(436)	(186)
Other liabilities						(39)	(60)	(137)
Net cash provided by (used in) operating activities						7,186	6,624	6,863
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(9,389)	(8,052)	(7,901)
Contributions to equity method investments						(416)	(414)	(307)
Acquisitions, net of cash acquired							(13)	(4,778)
Return of investment capital						137	281	1
Purchases of debt and equity securities						(3,762)	(4,071)	(5,153)
Proceeds from sales and maturities of debt and equity securities						3,747	4,098	5,236
Proceeds from the sales of discontinued operations and other assets, net of cash divested						41		1,418
Other						(418)	(271)	(44)
Net cash used in investing activities						(10,060)	(8,442)	(11,528)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						5,299	6,909	9,238
Proceeds from Issuance of Common Stock						1,838		731
Payments for the redemption of long-term debt						(2,906)	(2,316)	(1,923)
Proceeds from the issuance of short-term debt with original maturities greater than 90 days						472	319	2,081
Payments for the redemption of short-term debt with original maturities greater than 90 days						(282)	(272)	(2,166)
Notes payable and commercial paper						981	(409)	(1,362)
Dividends paid						(2,471)	(2,450)	(2,332)
Other						29	1	(16)
Net cash provided by financing activities						2,960	1,782	4,251
Changes in cash and cash equivalents included in assets held for sale								474
Net increase (decrease) in cash, cash equivalents, and restricted cash						86	(36)	60
Cash, cash equivalents, and restricted cash at beginning of period			505		541	505	541	481
Cash, cash equivalents, and restricted cash at end of period	$ 541	591		505		591	505	541
Cash and cash equivalents at beginning of period			358			358
Cash and cash equivalents at end of period		442		358		442	358
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						2,086	1,963	1,794
Cash (received from) paid for income taxes						(266)	4	229
Significant non-cash transactions:
Accrued capital expenditures						1,112	1,032	1,000
Non-cash dividends						107
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent		135	323	205	270	1,071	1,214	1,166
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						1,487	1,409	1,382
Equity component of AFUDC						(73)	(106)	(102)
Losses (Gains) on sales of other assets						1	(1)	5
Impairment charges						192		1
Deferred income taxes						305	410	470
Accrued pension and other post-retirement benefit costs						4	(4)	4
Contributions to qualified pension plans						(46)		(43)
Payments for asset retirement obligations						(230)	(271)	(287)
Provision for rate refunds						182
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions						2	9	5
Receivables						(86)	(9)	(76)
Receivables from affiliated companies						(87)	68	(56)
Inventory						25	78	215
Other current assets						(161)	7	67
Increase (decrease) in
Accounts payable						168	23	(69)
Accounts payable to affiliated companies						21	(38)	18
Taxes accrued						(65)	86	187
Other current liabilities						89	(161)	63
Other assets						(179)	(49)	20
Other liabilities						(90)	(31)	6
Net cash provided by (used in) operating activities						2,530	2,634	2,976
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(2,706)	(2,524)	(2,220)
Purchases of debt and equity securities						(1,810)	(2,124)	(2,832)
Proceeds from sales and maturities of debt and equity securities						1,810	2,128	2,832
Notes receivable from affiliated companies							66	97
Other						(147)	(109)	(83)
Net cash used in investing activities						(2,853)	(2,563)	(2,206)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						1,983	569	1,587
Payments for the redemption of long-term debt						(1,205)	(116)	(356)
Notes payable to affiliated companies						335	104
Distributions to parent						(750)	(625)	(2,000)
Other						(23)	(1)
Net cash provided by financing activities						340	(69)	(769)
Net increase in cash and cash equivalents						17	2	1
Cash and cash equivalents at beginning of period			16		14	16	14	13
Cash and cash equivalents at end of period	14	33		16		33	16	14
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						452	398	393
Cash (received from) paid for income taxes						89	193	(60)
Significant non-cash transactions:
Accrued capital expenditures						302	315	347
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net income		123	237	447	201	1,033	1,268	1,041
Net Income Attributable to Parent		123	235	444	199	1,027	1,258	1,031
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						1,987	1,516	1,435
Equity component of AFUDC						(104)	(92)	(76)
Losses (Gains) on sales of other assets						(24)	(28)	(34)
Impairment charges						87	156	7
Deferred income taxes						358	703	532
Accrued pension and other post-retirement benefit costs						24	(28)	(24)
Contributions to qualified pension plans						(45)		(43)
Payments for asset retirement obligations						(230)	(248)	(270)
Other rate case adjustments						37
Provision for rate refunds						122
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions						18		42
Receivables						(207)	(89)	7
Receivables from affiliated companies						(137)	71	211
Inventory						121	125	35
Other current assets						(12)	(397)	50
Increase (decrease) in
Accounts payable						217	(260)	252
Accounts payable to affiliated companies						109	(97)	37
Taxes accrued						8	17	15
Other current liabilities						129	(166)	(42)
Other assets						(913)	(300)	(248)
Other liabilities						(34)	(98)	(36)
Net cash provided by (used in) operating activities						2,544	2,053	2,891
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(3,854)	(3,152)	(3,306)
Asset acquisitions								(10)
Proceeds from the sales of other assets						20
Purchases of debt and equity securities						(1,753)	(1,806)	(2,143)
Proceeds from sales and maturities of debt and equity securities						1,769	1,824	2,187
Proceeds from insurance							7	58
Proceeds from the sale of nuclear fuel							20	20
Notes receivable from affiliated companies						240	(160)	(80)
Other						(182)	(86)	47
Net cash used in investing activities						(3,760)	(3,353)	(3,227)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						1,833	2,118	2,375
Payments for the redemption of long-term debt						(771)	(813)	(327)
Notes payable to affiliated companies						430	100	444
Dividends to parent						(250)	(124)	(2,098)
Other						(1)	(4)	(3)
Net cash provided by financing activities						1,241	1,277	391
Net increase (decrease) in cash, cash equivalents, and restricted cash						25	(23)	55
Cash, cash equivalents, and restricted cash at beginning of period			87		110	87	110	55
Cash, cash equivalents, and restricted cash at end of period	110	112		87		112	87	110
Cash and cash equivalents at beginning of period			40			40
Cash and cash equivalents at end of period		67		40		67	40
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						798	773	673
Cash (received from) paid for income taxes						(348)	(146)	(187)
Significant non-cash transactions:
Accrued capital expenditures						478	391	317
Equitization of certain notes payable to affiliates							1,047
Dividend to parent related to a legal entity restructuring							547
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent		135	177	168	147	667	715	599
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						1,183	936	907
Equity component of AFUDC						(57)	(47)	(50)
Losses (Gains) on sales of other assets						(9)	(5)	(6)
Impairment charges						33	19	1
Deferred income taxes						236	384	384
Accrued pension and other post-retirement benefit costs						15	(20)	(32)
Contributions to qualified pension plans						(25)		(24)
Payments for asset retirement obligations						(195)	(192)	(212)
Other rate case adjustments						37
Provision for rate refunds						122
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions						5	(4)	4
Receivables						(107)	(58)	(17)
Receivables from affiliated companies						(20)	2	11
Inventory						63	59	12
Other current assets						(201)	(75)	84
Increase (decrease) in
Accounts payable						219	(230)	181
Accounts payable to affiliated companies						99	(48)	37
Taxes accrued						(11)	(39)	90
Other current liabilities						46	(131)	114
Other assets						(484)	(53)	(163)
Other liabilities						12	(18)	12
Net cash provided by (used in) operating activities						1,628	1,195	1,932
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(2,220)	(1,715)	(1,733)
Proceeds from the sales of other assets						20
Purchases of debt and equity securities						(1,236)	(1,249)	(1,658)
Proceeds from sales and maturities of debt and equity securities						1,206	1,207	1,615
Proceeds from insurance							4
Notes receivable from affiliated companies							165	(165)
Other						(115)	(55)	26
Net cash used in investing activities						(2,345)	(1,643)	(1,915)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						845	812	505
Payments for the redemption of long-term debt						(3)	(470)	(15)
Notes payable to affiliated companies						54	240	(209)
Distributions to parent						(175)	(124)	(300)
Other						(1)	(1)	(2)
Net cash provided by financing activities						720	457	(21)
Net increase in cash and cash equivalents						3	9	(4)
Cash and cash equivalents at beginning of period			20		11	20	11	15
Cash and cash equivalents at end of period	11	23		20		23	20	11
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						303	291	248
Cash (received from) paid for income taxes						(112)	59	(287)
Significant non-cash transactions:
Accrued capital expenditures						220	191	147
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent		40	103	344	90	554	712	551
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						793	570	516
Equity component of AFUDC						(47)	(45)	(26)
Losses (Gains) on sales of other assets						(1)	(1)
Impairment charges						54	138	6
Deferred income taxes						159	245	224
Accrued pension and other post-retirement benefit costs						5	(13)	2
Contributions to qualified pension plans						(20)		(20)
Payments for asset retirement obligations						(35)	(56)	(58)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions						7	5	38
Receivables						(100)	(38)	23
Receivables from affiliated companies						(26)		21
Inventory						58	66	23
Other current assets						59	(138)	(86)
Increase (decrease) in
Accounts payable						(1)	(32)	71
Accounts payable to affiliated companies						17	(51)	9
Taxes accrued						40	1	(117)
Other current liabilities						82	(37)	(149)
Other assets						(428)	(229)	(84)
Other liabilities						(61)	(82)	(53)
Net cash provided by (used in) operating activities						1,109	1,015	891
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(1,634)	(1,437)	(1,583)
Purchases of debt and equity securities						(517)	(557)	(485)
Proceeds from sales and maturities of debt and equity securities						563	617	572
Proceeds from insurance							4	58
Proceeds from the sale of nuclear fuel							20	20
Notes receivable from affiliated companies						313	(313)
Other						(65)	(31)	21
Net cash used in investing activities						(1,340)	(1,697)	(1,397)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						988	1,306	1,870
Payments for the redemption of long-term debt						(769)	(342)	(12)
Notes payable to affiliated companies						108	(297)	(516)
Distributions to parent						(75)		(775)
Other						1	(1)
Net cash provided by financing activities						253	666	567
Net increase (decrease) in cash, cash equivalents, and restricted cash						22	(16)	61
Cash, cash equivalents, and restricted cash at beginning of period			53		69	53	69	8
Cash, cash equivalents, and restricted cash at end of period	69	75		53		75	53	69
Cash and cash equivalents at beginning of period			13			13
Cash and cash equivalents at end of period		36		13		36	13
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						270	274	208
Cash (received from) paid for income taxes						(120)	(197)	216
Significant non-cash transactions:
Accrued capital expenditures						258	199	170
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent		55	(25)	65	42	176	192	228
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						271	265	237
Equity component of AFUDC						(11)	(11)	(6)
Losses (Gains) on sales of other assets						106	(1)	(2)
Impairment charges							1
Deferred income taxes						25	90	55
Accrued pension and other post-retirement benefit costs						3	2	6
Contributions to qualified pension plans							(4)	(5)
Payments for asset retirement obligations						(3)	(7)	(5)
Provision for rate refunds						24
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions								(2)
Receivables						(33)	2	(4)
Receivables from affiliated companies						19	(4)	(36)
Inventory						7	6	(32)
Other current assets						16	(22)	79
Increase (decrease) in
Accounts payable						(19)	12	19
Accounts payable to affiliated companies						16	(1)	10
Taxes accrued						12	11	3
Other current liabilities						14	(19)	(54)
Other assets						(26)	(28)	(35)
Other liabilities						(27)	(5)	(31)
Net cash provided by (used in) operating activities						570	479	425
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(827)	(686)	(476)
Notes receivable from affiliated companies						14	80	(94)
Other						(89)	(41)	(30)
Net cash used in investing activities						(902)	(647)	(600)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						99	182	341
Payments for the redemption of long-term debt						(3)	(2)	(53)
Notes payable to affiliated companies						245	13	(87)
Capital contribution from parent						106
Dividends to parent							(25)	(25)
Other							(1)	(2)
Net cash provided by financing activities						341	167	174
Net increase in cash and cash equivalents						9	(1)	(1)
Cash and cash equivalents at beginning of period			12		13	12	13	14
Cash and cash equivalents at end of period	13	21		12		21	12	13
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						87	85	81
Cash (received from) paid for income taxes						(6)	(8)	(46)
Significant non-cash transactions:
Accrued capital expenditures						95	82	83
Transfer of ownership interest of certain equity method investees to parent						106
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent		76	100	36	91	393	354	381
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)						524	462	499
Equity component of AFUDC						(32)	(28)	(16)
Impairment charges						30	18	8
Deferred income taxes						95	152	213
Accrued pension and other post-retirement benefit costs						7	2	8
Contributions to qualified pension plans						(8)		(9)
Payments for asset retirement obligations						(69)	(45)	(46)
Provision for rate refunds						53
(Increase) decrease in
Receivables						7	59	(2)
Receivables from affiliated companies						3	(11)	(43)
Inventory						28	54	66
Other current assets						(25)	28	(67)
Increase (decrease) in
Accounts payable						37	(86)	8
Accounts payable to affiliated companies						5	4	(9)
Taxes accrued						(52)	64	(4)
Other current liabilities						14	(10)	(81)
Other assets						29	(28)	(27)
Other liabilities						(33)	(20)	(8)
Net cash provided by (used in) operating activities						1,006	969	871
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures						(832)	(840)	(755)
Purchases of debt and equity securities						(48)	(20)	(14)
Proceeds from sales and maturities of debt and equity securities						44	7	11
Proceeds from the sales of discontinued operations and other assets, net of cash divested						15
Notes receivable from affiliated companies							86	(3)
Other						3	(65)	32
Net cash used in investing activities						(818)	(832)	(729)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt								494
Payments for the redemption of long-term debt						(3)	(5)	(478)
Notes payable to affiliated companies						6	161
Distributions to parent						(175)	(300)	(149)
Other						(1)	(1)	(1)
Net cash provided by financing activities						(173)	(145)	(134)
Net increase in cash and cash equivalents						15	(8)	8
Cash and cash equivalents at beginning of period			9		17	9	17	9
Cash and cash equivalents at end of period	17	24		9		24	9	17
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized						162	179	171
Cash (received from) paid for income taxes						75	117	(7)
Significant non-cash transactions:
Accrued capital expenditures						88	125	99
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income Attributable to Parent	54	48	110	63	95	129	139		$ 193
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	25					161	151		148
Losses (Gains) on sales of other assets									(133)
Impairment charges							7
Deferred income taxes	26					(31)	154		74
Equity in (earnings) losses of unconsolidated affiliates	(2)					(7)	6		(29)
Accrued pension and other post-retirement benefit costs	5					(4)	23		3
Contributions to qualified pension plans	(10)						(11)		(14)
Payments for asset retirement obligations	(1)								(6)
Provision for rate refunds						43
(Increase) decrease in
Receivables	(157)					7	(40)		12
Receivables from affiliated companies						(15)			(7)
Inventory	(11)					(4)			14
Other current assets	8					71	(20)		(98)
Increase (decrease) in
Accounts payable	35					15	(13)		6
Accounts payable to affiliated companies	4					25	5		6
Taxes accrued	(2)					65	(48)		38
Other current liabilities	2					21	(9)		28
Other assets	(7)					6	7		(91)
Other liabilities	5					(4)	(2)		180
Net cash provided by (used in) operating activities	(26)					478	349		324
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(113)					(721)	(585)		(522)
Contributions to equity method investments	(12)						(12)		(47)
Proceeds from the sales of other assets									175
Return of investment capital	1					3	2		18
Other	1					(10)	(6)		5
Net cash used in investing activities	(124)					(731)	(603)		(389)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt						100	250		295
Proceeds from Issuance of Common Stock									122
Payments for the redemption of long-term debt							(35)		(40)
Notes payable and commercial paper	185						(330)		(195)
Notes payable to affiliated companies						(166)	364
Capital contribution from parent						300
Dividends to parent	(27)
Dividends paid									(114)
Other							(1)
Net cash provided by financing activities	158					234	248		68
Net increase in cash and cash equivalents	8					(19)	(6)		3
Cash and cash equivalents at beginning of period	17		$ 19		$ 25	19	25		14
Cash and cash equivalents at end of period	25	$ 0		$ 19		0	19	$ 25	17
Supplemental Disclosures:
Cash paid for interest, net of amount capitalized	11					79	78		81
Cash (received from) paid for income taxes						(16)	(12)		(25)
Significant non-cash transactions:
Accrued capital expenditures	$ 48					$ 96	34		$ 63
Transfer of ownership interest of certain equity method investees to parent							$ 149