Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 1,406	$ 1,211
Net income (attributable to parent)	1,402	1,203
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,953	1,868
Equity component of AFUDC	(125)	(87)
Gains on sales of other assets	(20)	(18)
Impairment charges	9	198
Deferred income taxes	669	285
Equity in earnings of unconsolidated affiliates	(65)	(23)
Accrued pension and other post-retirement benefit costs	13	8
Payments for asset retirement obligations	(272)	(263)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(12)	199
Receivables	293	(38)
Inventory	153	178
Other current assets	(148)	(51)
Increase (decrease) in
Accounts payable	(505)	(153)
Taxes accrued	41	216
Other current liabilities	(531)	(281)
Other assets	(101)	(9)
Other liabilities	(2)	(15)
Net cash provided by operating activities	2,756	3,225
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(3,931)	(3,393)
Contributions to equity method investments	(287)	(136)
Purchases of available-for-sale securities	(2,412)	(3,033)
Proceeds from sales and maturities of available-for-sale securities	2,439	3,059
Change in restricted cash	(44)	(21)
Other	(89)	(84)
Net cash used in investing activities	(4,324)	(3,608)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	2,734	3,514
Proceeds from the issuance of common stock related to employee benefit plans		7
Payments for the redemption of long-term debt	(1,009)	(795)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	230	500
Payments for the redemption of short-term debt with original maturities greater than 90 days	(32)	(492)
Notes payable and commercial paper	783	(1,349)
Dividends paid	(1,200)	(1,140)
Other	(32)	(43)
Net cash provided by financing activities	1,474	202
Changes in cash and cash equivalents associated with assets held for sale		79
Net decrease in cash and cash equivalents	(94)	(102)
Cash and cash equivalents at beginning of period	392	383
Cash and cash equivalents at end of period	298	281
Significant non-cash transactions:
Accrued capital expenditures	589	670
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	543	532
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	688	673
Equity component of AFUDC	(59)	(48)
Deferred income taxes	283	273
Accrued pension and other post-retirement benefit costs		2
Payments for asset retirement obligations	(123)	(118)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	24	3
Receivables	36	(48)
Receivable from affiliated companies	78	36
Inventory	(14)	102
Other current assets	(21)	24
Increase (decrease) in
Accounts payable	(125)	(226)
Accounts payable to affiliated companies	(120)	(56)
Taxes accrued	19	188
Other current liabilities	(140)	28
Other assets	(44)	22
Other liabilities	(15)	(14)
Net cash provided by operating activities	1,010	1,373
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,092)	(1,031)
Purchases of available-for-sale securities	(1,225)	(1,395)
Proceeds from sales and maturities of available-for-sale securities	1,228	1,395
Notes receivable from affiliated companies	66
Notes receivable from affiliated companies		(89)
Other	(29)	(41)
Net cash used in investing activities	(1,052)	(1,161)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		992
Payments for the redemption of long-term debt	(114)	(1)
Notes payable to affiliated companies	534
Distributions to parent	(375)	(1,200)
Other	(1)
Net cash provided by financing activities	44	(209)
Net decrease in cash and cash equivalents	2	3
Cash and cash equivalents at beginning of period	14	13
Cash and cash equivalents at end of period	16	16
Significant non-cash transactions:
Accrued capital expenditures	200	228
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	478	486
Net income (attributable to parent)	473	481
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	733	696
Equity component of AFUDC	(48)	(30)
Gains on sales of other assets	(15)	(15)
Impairment charges	2	3
Deferred income taxes	412	285
Accrued pension and other post-retirement benefit costs	(5)	(12)
Payments for asset retirement obligations	(128)	(126)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		32
Receivables	(64)	(66)
Receivable from affiliated companies	99	306
Inventory	95	25
Other current assets	(200)	45
Increase (decrease) in
Accounts payable	(211)	(26)
Accounts payable to affiliated companies	(140)	(79)
Taxes accrued	81	90
Other current liabilities	(148)	(162)
Other assets	(70)	(72)
Other liabilities	(18)	15
Net cash provided by operating activities	853	1,395
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,733)	(1,441)
Purchases of available-for-sale securities	(1,108)	(1,570)
Proceeds from sales and maturities of available-for-sale securities	1,123	1,594
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(60)
Change in restricted cash	5	(6)
Other	(26)	(14)
Net cash used in investing activities	(1,795)	(1,379)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	923	1,338
Payments for the redemption of long-term debt	(326)	(320)
Notes payable to affiliated companies	341	(392)
Dividends to parent		(651)
Other	(3)	(1)
Net cash provided by financing activities	935	(26)
Net decrease in cash and cash equivalents	(7)	(10)
Cash and cash equivalents at beginning of period	46	44
Cash and cash equivalents at end of period	39	34
Significant non-cash transactions:
Accrued capital expenditures	174	288
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	301	268
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	453	451
Equity component of AFUDC	(26)	(20)
Gains on sales of other assets	(4)	(3)
Deferred income taxes	224	172
Accrued pension and other post-retirement benefit costs	(10)	(16)
Payments for asset retirement obligations	(101)	(100)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(3)	(1)
Receivables	3	(19)
Receivable from affiliated companies		7
Inventory	23	20
Other current assets	(50)	131
Increase (decrease) in
Accounts payable	(218)	(28)
Accounts payable to affiliated companies	(58)	(56)
Taxes accrued	(43)	56
Other current liabilities	(111)	(12)
Other assets	(37)	(26)
Other liabilities	(9)	(6)
Net cash provided by operating activities	334	818
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(840)	(704)
Purchases of available-for-sale securities	(819)	(1,299)
Proceeds from sales and maturities of available-for-sale securities	805	1,284
Notes receivable from affiliated companies	165
Other	(22)	(19)
Net cash used in investing activities	(711)	(738)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	15	59
Payments for the redemption of long-term debt	(269)	(15)
Notes payable to affiliated companies	633	(131)
Other	(1)
Net cash provided by financing activities	378	(87)
Net decrease in cash and cash equivalents	1	(7)
Cash and cash equivalents at beginning of period	11	15
Cash and cash equivalents at end of period	12	8
Significant non-cash transactions:
Accrued capital expenditures	52	73
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	248	281
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	274	239
Equity component of AFUDC	(22)	(9)
Impairment charges	2	3
Deferred income taxes	186	113
Accrued pension and other post-retirement benefit costs	2	1
Payments for asset retirement obligations	(27)	(25)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	2	34
Receivables	(65)	(49)
Receivable from affiliated companies		23
Inventory	72	5
Other current assets	(47)	(13)
Increase (decrease) in
Accounts payable	7	3
Accounts payable to affiliated companies	(83)	(16)
Taxes accrued	78	5
Other current liabilities	(57)	(142)
Other assets	(32)	(47)
Other liabilities	(5)	20
Net cash provided by operating activities	533	426
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(893)	(737)
Purchases of available-for-sale securities	(289)	(271)
Proceeds from sales and maturities of available-for-sale securities	318	310
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(230)
Change in restricted cash		(6)
Other	(4)	5
Net cash used in investing activities	(1,094)	(641)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	908	1,278
Payments for the redemption of long-term debt	(57)	(5)
Notes payable to affiliated companies	(297)	(407)
Distributions to parent		(649)
Other	(1)	(2)
Net cash provided by financing activities	553	215
Net decrease in cash and cash equivalents	(8)
Cash and cash equivalents at beginning of period	16	8
Cash and cash equivalents at end of period	8	8
Significant non-cash transactions:
Accrued capital expenditures	122	215
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	72	82
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	132	127
Equity component of AFUDC	(5)	(2)
Gains on sales of other assets		(1)
Impairment charges	1
Deferred income taxes	64	68
Accrued pension and other post-retirement benefit costs	2	3
Payments for asset retirement obligations	(3)	(3)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		(2)
Receivables	11	3
Receivable from affiliated companies	55	49
Inventory	6	(5)
Other current assets	(11)	49
Increase (decrease) in
Accounts payable	(4)	8
Accounts payable to affiliated companies	(16)	23
Taxes accrued	(79)	(68)
Other current liabilities	(15)	(66)
Other assets	(12)	(8)
Other liabilities	(8)	(9)
Net cash provided by operating activities	190	248
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(286)	(214)
Notes receivable from affiliated companies	31
Notes receivable from affiliated companies		(186)
Other	(13)	(13)
Net cash used in investing activities	(268)	(413)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	93	341
Payments for the redemption of long-term debt	(1)	(52)
Notes payable to affiliated companies	8	(103)
Dividends to parent	(25)	(25)
Other	(1)
Net cash provided by financing activities	74	161
Net decrease in cash and cash equivalents	(4)	(4)
Cash and cash equivalents at beginning of period	13	14
Cash and cash equivalents at end of period	9	10
Significant non-cash transactions:
Accrued capital expenditures	59	30
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	197	180
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	218	223
Equity component of AFUDC	(12)	(7)
Deferred income taxes	131	36
Accrued pension and other post-retirement benefit costs	3	4
Payments for asset retirement obligations	(17)	(16)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1
Receivables	73	12
Receivable from affiliated companies	27	11
Inventory	34	62
Other current assets	(15)	(19)
Increase (decrease) in
Accounts payable	(68)	(22)
Accounts payable to affiliated companies	(24)	4
Taxes accrued	(3)	(42)
Other current liabilities	(11)	(60)
Other assets	(13)	(29)
Other liabilities	(9)	44
Net cash provided by operating activities	512	381
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(397)	(325)
Purchases of available-for-sale securities	(10)	(7)
Proceeds from sales and maturities of available-for-sale securities	4	5
Notes receivable from affiliated companies	67
Notes receivable from affiliated companies		(64)
Other	(23)	(6)
Net cash used in investing activities	(359)	(397)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		495
Payments for the redemption of long-term debt	(2)	(326)
Distributions to parent	(150)	(149)
Other	(1)	(1)
Net cash provided by financing activities	(153)	19
Net decrease in cash and cash equivalents		3
Cash and cash equivalents at beginning of period	17	9
Cash and cash equivalents at end of period	17	12
Significant non-cash transactions:
Accrued capital expenditures	81	43
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	87	106
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	74	74
Impairment charges	7
Deferred income taxes	100	70
Equity in earnings of unconsolidated affiliates	(5)	(23)
Accrued pension and other post-retirement benefit costs	6	2
Payments for asset retirement obligations		(4)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(39)	41
Receivables	155	90
Receivable from affiliated companies	(1)	48
Inventory	28
Other current assets	(64)	(93)
Increase (decrease) in
Accounts payable	(44)	(21)
Accounts payable to affiliated companies	42
Taxes accrued	(46)	8
Other current liabilities	(23)	(4)
Other assets	28	49
Other liabilities	(6)	3
Net cash provided by operating activities	299	346
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(260)	(247)
Contributions to equity method investments	(12)	(22)
Other	1	(1)
Net cash used in investing activities	(271)	(270)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	125
Proceeds from the issuance of common stock related to employee benefit plans		12
Payments for the redemption of long-term debt		(40)
Notes payable and commercial paper	(330)	(5)
Notes payable to affiliated companies	167
Dividends paid		(55)
Other	(1)
Net cash provided by financing activities	(39)	(88)
Net decrease in cash and cash equivalents	(11)	(12)
Cash and cash equivalents at beginning of period	25	33
Cash and cash equivalents at end of period	14	21
Significant non-cash transactions:
Accrued capital expenditures	45	$ 50
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