Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 2,361	$ 2,392
Net income (attributable to parent)	2,356	2,379
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	2,990	2,847
Equity component of AFUDC	(175)	(140)
Gains on sales of other assets	(28)	(27)
Impairment charges	216	279
Deferred income taxes	1,016	648
Equity in earnings of unconsolidated affiliates	(101)	(34)
Accrued pension and other post-retirement benefit costs	19	12
Contributions to qualified pension plans	(8)
Payments for asset retirement obligations	(420)	(443)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	4	36
Receivables	80	(276)
Inventory	248	455
Other current assets	(176)	(163)
Increase (decrease) in
Accounts payable	(554)	(207)
Taxes accrued	233	417
Other current liabilities	(532)	(157)
Other assets	(160)	(64)
Other liabilities	(2)	36
Net cash provided by operating activities	5,011	5,611
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(5,841)	(5,252)
Contributions to equity method investments	(370)	(198)
Purchases of available-for-sale securities	(3,170)	(4,048)
Proceeds from sales and maturities of available-for-sale securities	3,199	4,107
Change in restricted cash	(29)	(34)
Other	(149)	(130)
Net cash used in investing activities	(6,360)	(5,555)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	5,710	8,647
Proceeds from the issuance of common stock related to employee benefit plans		7
Payments for the redemption of long-term debt	(2,035)	(988)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	265	1,424
Payments for the redemption of short-term debt with original maturities greater than 90 days	(237)	(492)
Notes payable and commercial paper	(647)	(1,579)
Dividends paid	(1,825)	(1,731)
Other	8	(22)
Net cash provided by financing activities	1,239	5,266
Changes in cash and cash equivalents associated with assets held for sale		11
Net decrease in cash and cash equivalents	(110)	5,333
Cash and cash equivalents at beginning of period	392	383
Cash and cash equivalents at end of period	282	5,716
Significant non-cash transactions:
Accrued capital expenditures	740	631
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	1,009	1,026
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,051	1,020
Equity component of AFUDC	(79)	(75)
Gains on sales of other assets		1
Deferred income taxes	330	382
Accrued pension and other post-retirement benefit costs		3
Payments for asset retirement obligations	(201)	(204)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1	4
Receivables	(40)	(191)
Receivable from affiliated companies	17	19
Inventory	50	217
Other current assets	8	81
Increase (decrease) in
Accounts payable	(78)	(179)
Accounts payable to affiliated companies	(88)	(100)
Taxes accrued	225	248
Other current liabilities	(149)	51
Other assets	(18)	57
Other liabilities	(26)	(15)
Net cash provided by operating activities	2,012	2,345
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,747)	(1,531)
Purchases of available-for-sale securities	(1,660)	(2,070)
Proceeds from sales and maturities of available-for-sale securities	1,664	2,070
Notes receivable from affiliated companies	66	131
Other	(58)	(65)
Net cash used in investing activities	(1,735)	(1,465)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		992
Payments for the redemption of long-term debt	(115)	(3)
Notes payable to affiliated companies	468
Distributions to parent	(625)	(1,800)
Other	(1)
Net cash provided by financing activities	(273)	(811)
Net decrease in cash and cash equivalents	4	69
Cash and cash equivalents at beginning of period	14	13
Cash and cash equivalents at end of period	18	82
Significant non-cash transactions:
Accrued capital expenditures	292	228
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	821	935
Net income (attributable to parent)	814	927
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,130	1,071
Equity component of AFUDC	(68)	(51)
Gains on sales of other assets	(20)	(23)
Impairment charges	137	4
Deferred income taxes	651	425
Accrued pension and other post-retirement benefit costs	(9)	(19)
Payments for asset retirement obligations	(190)	(203)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1	33
Receivables	(182)	(155)
Receivable from affiliated companies	102	329
Inventory	126	99
Other current assets	(279)	(30)
Increase (decrease) in
Accounts payable	(281)	(24)
Accounts payable to affiliated companies	(59)	(109)
Taxes accrued	143	159
Other current liabilities	(184)	(156)
Other assets	(100)	(90)
Other liabilities	(85)	(4)
Net cash provided by operating activities	1,654	2,191
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,419)	(2,286)
Purchases of available-for-sale securities	(1,393)	(1,849)
Proceeds from sales and maturities of available-for-sale securities	1,411	1,899
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(90)	(43)
Change in restricted cash	5	(6)
Other	(40)	(17)
Net cash used in investing activities	(2,522)	(2,244)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,720	2,375
Payments for the redemption of long-term debt	(611)	(327)
Notes payable to affiliated companies	(129)	(798)
Dividends to parent	(125)	(1,075)
Other	(3)	(1)
Net cash provided by financing activities	852	174
Net decrease in cash and cash equivalents	(16)	121
Cash and cash equivalents at beginning of period	46	44
Cash and cash equivalents at end of period	30	165
Significant non-cash transactions:
Accrued capital expenditures	174	228
Equitization of certain notes payable to affiliates	1,047
Dividend to parent related to a legal restructuring	547
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	547	539
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	691	679
Equity component of AFUDC	(35)	(34)
Gains on sales of other assets	(4)	(4)
Impairment charges		1
Deferred income taxes	287	325
Accrued pension and other post-retirement benefit costs	(15)	(24)
Payments for asset retirement obligations	(149)	(163)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(2)
Receivables	(47)	(78)
Receivable from affiliated companies	(3)	11
Inventory	52	91
Other current assets	(34)	37
Increase (decrease) in
Accounts payable	(286)	(44)
Accounts payable to affiliated companies	(20)	(47)
Taxes accrued	33	76
Other current liabilities	(139)	37
Other assets	(49)	(32)
Other liabilities	(9)	(10)
Net cash provided by operating activities	818	1,360
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,247)	(1,106)
Purchases of available-for-sale securities	(995)	(1,470)
Proceeds from sales and maturities of available-for-sale securities	974	1,448
Notes receivable from affiliated companies	64	(65)
Other	(26)	(27)
Net cash used in investing activities	(1,230)	(1,220)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	812	505
Payments for the redemption of long-term debt	(270)	(15)
Notes payable to affiliated companies		(209)
Dividends to parent	(125)	(301)
Other	(1)	1
Net cash provided by financing activities	416	(19)
Net decrease in cash and cash equivalents	4	121
Cash and cash equivalents at beginning of period	11	15
Cash and cash equivalents at end of period	15	136
Significant non-cash transactions:
Accrued capital expenditures	116	66
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	368	487
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	431	383
Equity component of AFUDC	(33)	(16)
Impairment charges	137	4
Deferred income taxes	366	136
Accrued pension and other post-retirement benefit costs	3	2
Payments for asset retirement obligations	(41)	(41)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	3	34
Receivables	(140)	(78)
Receivable from affiliated companies	1	41
Inventory	74	8
Other current assets	(162)	(32)
Increase (decrease) in
Accounts payable	6	20
Accounts payable to affiliated companies	(35)	(55)
Taxes accrued	109	61
Other current liabilities	(45)	(183)
Other assets	(35)	(56)
Other liabilities	(71)	1
Net cash provided by operating activities	936	716
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,172)	(1,179)
Purchases of available-for-sale securities	(398)	(379)
Proceeds from sales and maturities of available-for-sale securities	437	450
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(70)
Change in restricted cash		(6)
Other	(14)	10
Net cash used in investing activities	(1,213)	(1,046)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	908	1,870
Payments for the redemption of long-term debt	(341)	(12)
Notes payable to affiliated companies	(297)	(750)
Distributions to parent		(774)
Other	(1)	(2)
Net cash provided by financing activities	269	332
Net decrease in cash and cash equivalents	(8)	2
Cash and cash equivalents at beginning of period	16	8
Cash and cash equivalents at end of period	8	10
Significant non-cash transactions:
Accrued capital expenditures	102	162
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	127	171
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	196	178
Equity component of AFUDC	(8)	(4)
Gains on sales of other assets	(1)	(2)
Impairment charges	1
Deferred income taxes	70	36
Accrued pension and other post-retirement benefit costs	3	4
Contributions to qualified pension plans	(4)
Payments for asset retirement obligations	(4)	(4)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1
Receivables	3	(1)
Receivable from affiliated companies	48	(3)
Inventory	1	(5)
Other current assets	(8)	50
Increase (decrease) in
Accounts payable	(48)	13
Accounts payable to affiliated companies	(4)	(4)
Taxes accrued	(21)	(13)
Other current liabilities	(6)	(53)
Other assets	(13)	(8)
Other liabilities	(2)	(28)
Net cash provided by operating activities	331	327
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(457)	(334)
Notes receivable from affiliated companies	7	(47)
Other	(25)	(21)
Net cash used in investing activities	(475)	(402)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	182	341
Payments for the redemption of long-term debt	(2)	(53)
Notes payable to affiliated companies	(16)	(103)
Dividends to parent	(25)	(25)
Other	(1)
Net cash provided by financing activities	138	160
Net decrease in cash and cash equivalents	(6)	85
Cash and cash equivalents at beginning of period	13	14
Cash and cash equivalents at end of period	7	99
Significant non-cash transactions:
Accrued capital expenditures	65	56
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	318	309
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	339	347
Equity component of AFUDC	(20)	(11)
Gains on sales of other assets	(1)
Impairment charges		8
Deferred income taxes	101	122
Accrued pension and other post-retirement benefit costs	4	6
Payments for asset retirement obligations	(26)	(31)
(Increase) decrease in
Receivables	53	16
Receivable from affiliated companies	31	(3)
Inventory	54	146
Other current assets	18	(105)
Increase (decrease) in
Accounts payable	(71)	(14)
Accounts payable to affiliated companies	(1)	(1)
Taxes accrued	115	12
Other current liabilities	(18)	(85)
Other assets	(24)	(38)
Other liabilities	32	64
Net cash provided by operating activities	904	742
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(603)	(540)
Purchases of available-for-sale securities	(15)	(12)
Proceeds from sales and maturities of available-for-sale securities	6	9
Notes receivable from affiliated companies	57	45
Other	(40)	(28)
Net cash used in investing activities	(595)	(526)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		495
Payments for the redemption of long-term debt	(3)	(476)
Distributions to parent	(300)	(149)
Other	(1)	(1)
Net cash provided by financing activities	(304)	(131)
Net decrease in cash and cash equivalents	5	85
Cash and cash equivalents at beginning of period	17	9
Cash and cash equivalents at end of period	22	94
Significant non-cash transactions:
Accrued capital expenditures	101	56
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	76	94
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	112	111
Impairment charges	7
Deferred income taxes	127	50
Equity in earnings of unconsolidated affiliates	(8)	(25)
Accrued pension and other post-retirement benefit costs	9	2
Contributions to qualified pension plans		(1)
Payments for asset retirement obligations		(5)
(Increase) decrease in
Receivables	157	88
Receivable from affiliated companies	(1)
Inventory	13	33
Other current assets	(129)	(50)
Increase (decrease) in
Accounts payable	(52)	11
Accounts payable to affiliated companies	(1)
Taxes accrued	(37)	12
Other current liabilities	(21)	(11)
Other assets	(9)	55
Other liabilities	(7)	17
Net cash provided by operating activities	236	381
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(407)	(416)
Contributions to equity method investments	(12)	(40)
Other	2	(2)
Net cash used in investing activities	(417)	(458)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	250	296
Proceeds from the issuance of common stock related to employee benefit plans		121
Payments for the redemption of long-term debt	(35)	(40)
Notes payable and commercial paper	(330)	(210)
Notes payable to affiliated companies	284
Dividends paid		(82)
Other	(1)
Net cash provided by financing activities	168	85
Net decrease in cash and cash equivalents	(13)	8
Cash and cash equivalents at beginning of period	25	33
Cash and cash equivalents at end of period	12	41
Significant non-cash transactions:
Accrued capital expenditures	47	$ 30
Transfer of Ownership Interest in Investments [Member] | Piedmont Natural Gas [Member]
Significant non-cash transactions:
Transfer of ownership interest of certain equity method investees to parent	$ 149