Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 717	$ 699
Net income (attributable to parent)	716	694
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	991	931
Equity component of AFUDC	(62)	(42)
Gains on sales of other assets	(11)	(9)
Impairment charges		3
Deferred income taxes	342	181
Equity in earnings of unconsolidated affiliates	(29)	(8)
Accrued pension and other post-retirement benefit costs	6	4
Payments for asset retirement obligations	(134)	(112)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(38)	102
Receivables	343	139
Inventory	155	89
Other current assets	16	13
Increase (decrease) in
Accounts payable	(463)	(210)
Taxes accrued	(28)	40
Other current liabilities	(478)	(81)
Other assets	(40)	45
Other liabilities	2	(102)
Net cash provided by operating activities	1,289	1,682
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,160)	(1,645)
Contributions to equity method investments	(175)	(59)
Purchases of available-for-sale securities	(1,386)	(1,347)
Proceeds from sales and maturities of available-for-sale securities	1,405	1,362
Change in restricted cash	(34)	(32)
Other	(49)	(37)
Net cash used in investing activities	(2,399)	(1,758)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,563	1,140
Proceeds from the issuance of common stock related to employee benefit plans		7
Payments for the redemption of long-term debt	(408)	(389)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	25
Payments for the redemption of short-term debt with original maturities greater than 90 days	(7)	(92)
Notes payable and commercial paper	1,045	(66)
Change in bank overdrafts	5
Dividends paid	(600)	(570)
Other	(27)	(33)
Net cash provided by (used in) financing activities	1,596	(3)
Change in cash and cash equivalents associated with assets held for sale		30
Net increase (decrease) in cash and cash equivalents	486	(49)
Cash and cash equivalents at beginning of period	392	383
Cash and cash equivalents at end of period	878	334
Significant non-cash transactions:
Accrued capital expenditures	575	576
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	270	271
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	339	330
Equity component of AFUDC	(30)	(23)
Deferred income taxes	162	145
Accrued pension and other post-retirement benefit costs		1
Payments for asset retirement obligations	(65)	(52)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	3	3
Receivables	66	2
Receivable from affiliated companies	54	33
Inventory	4	40
Other current assets	(26)	102
Increase (decrease) in
Accounts payable	(131)	(165)
Accounts payable to affiliated companies	3	21
Taxes accrued	(53)	52
Other current liabilities	(125)	21
Other assets	(3)	26
Other liabilities	(2)	(26)
Net cash provided by operating activities	466	781
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(563)	(459)
Purchases of available-for-sale securities	(722)	(785)
Proceeds from sales and maturities of available-for-sale securities	722	785
Notes receivable from affiliated companies	66
Notes receivable from affiliated companies		(691)
Other	(20)	(18)
Net cash used in investing activities	(517)	(1,168)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		992
Payments for the redemption of long-term debt	(113)	(1)
Notes payable to affiliated companies	337
Distributions to parent	(175)	(600)
Other	(1)
Net cash provided by (used in) financing activities	48	391
Net increase (decrease) in cash and cash equivalents	(3)	4
Cash and cash equivalents at beginning of period	14	13
Cash and cash equivalents at end of period	11	17
Significant non-cash transactions:
Accrued capital expenditures	164	179
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	201	212
Net income (attributable to parent)	199	209
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	365	342
Equity component of AFUDC	(24)	(14)
Gains on sales of other assets	(9)	(7)
Impairment charges		2
Deferred income taxes	220	182
Accrued pension and other post-retirement benefit costs	(3)	(6)
Payments for asset retirement obligations	(60)	(54)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(2)	6
Receivables	115	70
Receivable from affiliated companies	100	295
Inventory	65	3
Other current assets	(173)	(76)
Increase (decrease) in
Accounts payable	(228)	9
Accounts payable to affiliated companies	(32)	(55)
Taxes accrued	12	42
Other current liabilities	(121)	(64)
Other assets	(53)	(46)
Other liabilities	(14)	(7)
Net cash provided by operating activities	359	834
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,011)	(750)
Purchases of available-for-sale securities	(629)	(533)
Proceeds from sales and maturities of available-for-sale securities	635	548
Proceeds from Insurance	4	43
Notes receivable from affiliated companies	(104)
Change in restricted cash	5
Other	(4)	(15)
Net cash used in investing activities	(1,104)	(707)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	892	53
Payments for the redemption of long-term debt	(288)	(310)
Notes payable to affiliated companies	137	128
Distributions to noncontrolling interests	(1)	(1)
Other	(3)
Net cash provided by (used in) financing activities	737	(130)
Net increase (decrease) in cash and cash equivalents	(8)	(3)
Cash and cash equivalents at beginning of period	46	44
Cash and cash equivalents at end of period	38	41
Significant non-cash transactions:
Accrued capital expenditures	219	228
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	147	137
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	228	223
Equity component of AFUDC	(13)	(10)
Gains on sales of other assets	(3)	(2)
Deferred income taxes	120	100
Accrued pension and other post-retirement benefit costs	(5)	(8)
Payments for asset retirement obligations	(47)	(42)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(2)	(1)
Receivables	65	18
Receivable from affiliated companies	(1)	10
Inventory	23	15
Other current assets	(60)	83
Increase (decrease) in
Accounts payable	(192)	(16)
Accounts payable to affiliated companies	17	(14)
Taxes accrued	(68)	18
Other current liabilities	(81)	(39)
Other assets	(44)	(17)
Other liabilities	(10)	(4)
Net cash provided by operating activities	74	451
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(474)	(379)
Purchases of available-for-sale securities	(476)	(390)
Proceeds from sales and maturities of available-for-sale securities	470	384
Notes receivable from affiliated companies	165
Other	(9)	(13)
Net cash used in investing activities	(324)	(398)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		53
Payments for the redemption of long-term debt	(250)	(8)
Notes payable to affiliated companies	502	(101)
Other	(2)	(1)
Net cash provided by (used in) financing activities	250	(57)
Net increase (decrease) in cash and cash equivalents		(4)
Cash and cash equivalents at beginning of period	11	15
Cash and cash equivalents at end of period	11	11
Significant non-cash transactions:
Accrued capital expenditures	66	55
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	90	110
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	134	116
Equity component of AFUDC	(11)	(4)
Impairment charges	1	2
Deferred income taxes	100	83
Accrued pension and other post-retirement benefit costs	1	1
Payments for asset retirement obligations	(14)	(12)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		7
Receivables	51	52
Receivable from affiliated companies	(1)	14
Inventory	42	(12)
Other current assets	(33)	(44)
Increase (decrease) in
Accounts payable	(35)	25
Accounts payable to affiliated companies	(48)	(40)
Taxes accrued	29	(70)
Other current liabilities	(47)	(14)
Other assets	(13)	(30)
Other liabilities	(5)	(6)
Net cash provided by operating activities	241	178
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(538)	(370)
Purchases of available-for-sale securities	(153)	(143)
Proceeds from sales and maturities of available-for-sale securities	165	164
Proceeds from Insurance	4	43
Notes receivable from affiliated companies	(293)
Other	9	(1)
Net cash used in investing activities	(806)	(307)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	892
Payments for the redemption of long-term debt	(38)	(2)
Notes payable to affiliated companies	(297)	135
Other	(1)
Net cash provided by (used in) financing activities	556	133
Net increase (decrease) in cash and cash equivalents	(9)	4
Cash and cash equivalents at beginning of period	16	8
Cash and cash equivalents at end of period	7	12
Significant non-cash transactions:
Accrued capital expenditures	153	173
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	42	59
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	68	62
Equity component of AFUDC	(2)	(1)
Gains on sales of other assets		(1)
Deferred income taxes	30	11
Accrued pension and other post-retirement benefit costs	1	1
Payments for asset retirement obligations	(2)	(1)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1	2
Receivables	7	(18)
Receivable from affiliated companies	41	(9)
Inventory	19	1
Other current assets	9	78
Increase (decrease) in
Accounts payable	(10)	(1)
Accounts payable to affiliated companies	1
Taxes accrued	(52)	(31)
Other current liabilities	9	14
Other assets	(6)	(2)
Other liabilities	(3)
Net cash provided by operating activities	153	164
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(143)	(85)
Notes receivable from affiliated companies	(85)	(19)
Other	(8)	(4)
Net cash used in investing activities	(236)	(108)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	93	95
Payments for the redemption of long-term debt	(1)	(51)
Notes payable to affiliated companies	(8)	(95)
Other	(1)
Net cash provided by (used in) financing activities	83	(51)
Net increase (decrease) in cash and cash equivalents		5
Cash and cash equivalents at beginning of period	13	14
Cash and cash equivalents at end of period	13	19
Significant non-cash transactions:
Accrued capital expenditures	57	31
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	91	95
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	126	127
Equity component of AFUDC	(6)	(3)
Deferred income taxes	37	(16)
Accrued pension and other post-retirement benefit costs	1	2
Payments for asset retirement obligations	(7)	(5)
(Increase) decrease in
Receivables	44	16
Receivable from affiliated companies	26	7
Inventory	26	45
Other current assets	(2)	(19)
Increase (decrease) in
Accounts payable	(32)	(44)
Accounts payable to affiliated companies	1	(22)
Taxes accrued	41	30
Other current liabilities	(15)	(18)
Other assets	(11)	(4)
Other liabilities	(3)	(11)
Net cash provided by operating activities	317	180
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(189)	(151)
Purchases of available-for-sale securities	(4)	(5)
Proceeds from sales and maturities of available-for-sale securities	2	4
Notes receivable from affiliated companies	(113)	(19)
Other	(12)	(1)
Net cash used in investing activities	(316)	(172)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	(2)
Other	(1)
Net cash provided by (used in) financing activities	(3)
Net increase (decrease) in cash and cash equivalents	(2)	8
Cash and cash equivalents at beginning of period	17	9
Cash and cash equivalents at end of period	15	17
Significant non-cash transactions:
Accrued capital expenditures	84	42
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	95	103
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	37	37
Deferred income taxes	50	68
Equity in earnings of unconsolidated affiliates	(3)	(16)
Accrued pension and other post-retirement benefit costs	3	1
Payments for asset retirement obligations		(1)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(41)
Receivables	40	(14)
Inventory	37	49
Other current assets	24	20
Increase (decrease) in
Accounts payable	(31)	(21)
Accounts payable to affiliated companies	(5)
Taxes accrued	2	3
Other current liabilities	(17)	(9)
Other assets	25	23
Other liabilities	(1)	(20)
Net cash provided by operating activities	215	223
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(141)	(132)
Contributions to equity method investments	(12)	(9)
Other	(3)	(1)
Net cash used in investing activities	(156)	(142)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of common stock related to employee benefit plans		7
Notes payable and commercial paper	(330)	(80)
Notes payable to affiliated companies	261
Dividends paid		(27)
Net cash provided by (used in) financing activities	(69)	(100)
Net increase (decrease) in cash and cash equivalents	(10)	(19)
Cash and cash equivalents at beginning of period	25	33
Cash and cash equivalents at end of period	15	14
Significant non-cash transactions:
Accrued capital expenditures	$ 24	$ 43