Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 421	$ 358
Receivables (net of allowance for doubtful accounts)	759	779
Receivables of VIEs (net of allowance for doubtful accounts)	1,984	1,995
Inventory	3,149	3,250
Regulatory assets	1,544	1,437
Other	422	634
Total current assets	8,279	8,453
Property, Plant and Equipment
Cost	129,281	127,507
Accumulated depreciation and amortization	(42,307)	(41,537)
Generation facilities to be retired, net	399	421
Net property, plant and equipment	87,373	86,391
Other Noncurrent Assets
Goodwill	19,396	19,396
Regulatory assets	12,218	12,442
Nuclear decommissioning trust funds	7,024	7,097
Investments in equity method unconsolidated affiliates	1,189	1,175
Other	3,062	2,960
Total other noncurrent assets	42,889	43,070
Total Assets	138,541	137,914
Current Liabilities
Accounts payable	2,391	3,043
Notes payable and commercial paper	2,969	2,163
Taxes accrued	422	551
Interest accrued	542	525
Current maturities of long-term debt	3,951	3,244
Asset retirement obligations	676	689
Regulatory liabilities	505	402
Other	1,542	1,865
Total current liabilities	12,998	12,482
Long-Term Debt	49,030	49,035
Other Noncurrent Liabilities
Deferred income taxes	6,855	6,621
Asset retirement obligations	9,484	9,486
Regulatory liabilities	15,283	15,330
Accrued pension and other post-retirement benefit costs	1,018	1,103
Investment tax credits	537	539
Other	1,538	1,581
Total other noncurrent liabilities	34,715	34,660
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	38,839	38,792
Retained earnings	3,021	3,013
Accumulated other comprehensive loss	(69)	(67)
Total Parent stockholders' equity	41,792	41,739
Noncontrolling interests	6	(2)
Total equity	41,798	41,737
Total Liabilities and Equity	138,541	137,914
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	3	16
Receivables (net of allowance for doubtful accounts)	194	200
Receivables of VIEs (net of allowance for doubtful accounts)	634	640
Receivables from affiliated companies	106	95
Inventory	980	971
Regulatory assets	331	299
Other	42	19
Total current assets	2,290	2,240
Property, Plant and Equipment
Cost	43,562	42,939
Accumulated depreciation and amortization	(15,404)	(15,063)
Net property, plant and equipment	28,158	27,876
Other Noncurrent Assets
Regulatory assets	2,825	2,853
Nuclear decommissioning trust funds	3,734	3,772
Other	1,023	979
Total other noncurrent assets	7,582	7,604
Total Assets	38,030	37,720
Current Liabilities
Accounts payable	726	842
Accounts payable to affiliated companies	259	209
Notes payable to affiliated companies	45	104
Taxes accrued	84	234
Interest accrued	144	108
Current maturities of long-term debt	805	1,205
Asset retirement obligations	281	337
Regulatory liabilities	116	126
Other	369	486
Total current liabilities	2,829	3,651
Long-Term Debt	9,589	8,598
Long-Term Debt Payable to Affiliated Companies	300	300
Other Noncurrent Liabilities
Deferred income taxes	3,493	3,413
Asset retirement obligations	3,318	3,273
Regulatory liabilities	6,208	6,231
Accrued pension and other post-retirement benefit costs	95	95
Investment tax credits	231	232
Other	532	566
Total other noncurrent liabilities	13,877	13,810
Commitments and Contingencies
Equity
Member's equity	11,441	11,368
Accumulated other comprehensive loss	(6)	(7)
Total member's equity	11,435	11,361
Total Liabilities and Equity	38,030	37,720
Progress Energy [Member]
Current Assets
Cash and cash equivalents	20	40
Receivables (net of allowance for doubtful accounts)	122	123
Receivables of VIEs (net of allowance for doubtful accounts)	815	780
Receivables from affiliated companies	2	31
Notes receivable from affiliated companies	113	240
Inventory	1,537	1,592
Regulatory assets	869	741
Other	259	334
Total current assets	3,737	3,881
Property, Plant and Equipment
Cost	47,915	47,323
Accumulated depreciation and amortization	(16,060)	(15,857)
Generation facilities to be retired, net	399	421
Net property, plant and equipment	32,254	31,887
Other Noncurrent Assets
Goodwill	3,655	3,655
Regulatory assets	5,872	6,010
Nuclear decommissioning trust funds	3,290	3,324
Other	990	931
Total other noncurrent assets	13,807	13,920
Total Assets	49,798	49,688
Current Liabilities
Accounts payable	760	1,006
Accounts payable to affiliated companies	284	251
Notes payable to affiliated companies	982	805
Taxes accrued	109	101
Interest accrued	213	212
Current maturities of long-term debt	1,820	771
Asset retirement obligations	326	295
Regulatory liabilities	272	213
Other	637	729
Total current liabilities	5,403	4,383
Long-Term Debt	15,787	16,916
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	3,603	3,502
Asset retirement obligations	5,091	5,119
Regulatory liabilities	5,227	5,306
Accrued pension and other post-retirement benefit costs	527	545
Other	307	302
Total other noncurrent liabilities	14,755	14,774
Commitments and Contingencies
Equity
Additional paid-in capital	9,142	9,143
Retained earnings	4,591	4,350
Accumulated other comprehensive loss	(29)	(25)
Total Parent stockholders' equity	13,704	13,468
Noncontrolling interests	(1)	(3)
Total equity	13,703	13,465
Total Liabilities and Equity	49,798	49,688
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	8	20
Receivables (net of allowance for doubtful accounts)	50	56
Receivables of VIEs (net of allowance for doubtful accounts)	497	459
Receivables from affiliated companies	5	3
Inventory	1,002	1,017
Regulatory assets	476	352
Other	55	97
Total current assets	2,093	2,004
Property, Plant and Equipment
Cost	29,866	29,583
Accumulated depreciation and amortization	(11,012)	(10,903)
Generation facilities to be retired, net	399	421
Net property, plant and equipment	19,253	19,101
Other Noncurrent Assets
Regulatory assets	3,480	3,507
Nuclear decommissioning trust funds	2,568	2,588
Other	641	599
Total other noncurrent assets	6,689	6,694
Total Assets	28,035	27,799
Current Liabilities
Accounts payable	342	402
Accounts payable to affiliated companies	208	179
Notes payable to affiliated companies	354	240
Taxes accrued	36	64
Interest accrued	86	102
Current maturities of long-term debt	603	3
Asset retirement obligations	323	295
Regulatory liabilities	184	139
Other	324	376
Total current liabilities	2,460	1,800
Long-Term Debt	6,604	7,204
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	1,932	1,883
Asset retirement obligations	4,356	4,378
Regulatory liabilities	3,973	3,999
Accrued pension and other post-retirement benefit costs	246	248
Investment tax credits	142	143
Other	46	45
Total other noncurrent liabilities	10,695	10,696
Commitments and Contingencies
Equity
Total member's equity	8,126	7,949
Total Liabilities and Equity	28,035	27,799
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	6	13
Receivables (net of allowance for doubtful accounts)	71	65
Receivables of VIEs (net of allowance for doubtful accounts)	318	321
Receivables from affiliated companies	1	2
Notes receivable from affiliated companies	153	313
Inventory	535	574
Regulatory assets	393	389
Other	40	86
Total current assets	1,517	1,763
Property, Plant and Equipment
Cost	18,040	17,730
Accumulated depreciation and amortization	(5,042)	(4,947)
Net property, plant and equipment	12,998	12,783
Other Noncurrent Assets
Regulatory assets	2,391	2,503
Nuclear decommissioning trust funds	722	736
Other	301	284
Total other noncurrent assets	3,414	3,523
Total Assets	17,929	18,069
Current Liabilities
Accounts payable	416	602
Accounts payable to affiliated companies	82	74
Taxes accrued	72	34
Interest accrued	74	56
Current maturities of long-term debt	768	768
Asset retirement obligations	3	0
Regulatory liabilities	88	74
Other	299	334
Total current liabilities	1,802	1,942
Long-Term Debt	6,247	6,327
Other Noncurrent Liabilities
Deferred income taxes	1,812	1,761
Asset retirement obligations	735	742
Regulatory liabilities	1,254	1,307
Accrued pension and other post-retirement benefit costs	248	264
Other	110	108
Total other noncurrent liabilities	4,159	4,182
Commitments and Contingencies
Equity
Member's equity	5,723	5,614
Accumulated other comprehensive loss	(2)	4
Total member's equity	5,721	5,618
Total Liabilities and Equity	17,929	18,069
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	12	12
Receivables (net of allowance for doubtful accounts)	69	68
Receivables from affiliated companies	77	133
Notes receivable from affiliated companies		14
Inventory	108	133
Regulatory assets	43	49
Other	24	39
Total current assets	333	448
Property, Plant and Equipment
Cost	8,892	8,732
Accumulated depreciation and amortization	(2,729)	(2,691)
Net property, plant and equipment	6,163	6,041
Other Noncurrent Assets
Goodwill	920	920
Regulatory assets	432	445
Other	48	21
Total other noncurrent assets	1,400	1,386
Total Assets	7,896	7,875
Current Liabilities
Accounts payable	269	313
Accounts payable to affiliated companies	72	62
Notes payable to affiliated companies	130	29
Taxes accrued	145	190
Interest accrued	33	21
Current maturities of long-term debt	3	3
Asset retirement obligations	4	3
Regulatory liabilities	53	36
Other	66	71
Total current liabilities	775	728
Long-Term Debt	2,039	2,039
Long-Term Debt Payable to Affiliated Companies	25	25
Other Noncurrent Liabilities
Deferred income taxes	766	781
Asset retirement obligations	79	81
Regulatory liabilities	888	891
Accrued pension and other post-retirement benefit costs	81	59
Other	105	108
Total other noncurrent liabilities	1,919	1,920
Commitments and Contingencies
Equity
Common stock	762	762
Additional paid-in capital	2,670	2,670
Retained earnings	(294)	(269)
Total Parent stockholders' equity	3,138	3,163
Total Liabilities and Equity	7,896	7,875
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	15	9
Receivables (net of allowance for doubtful accounts)	56	57
Receivables from affiliated companies	99	125
Inventory	453	450
Regulatory assets	170	165
Other	30	30
Total current assets	823	836
Property, Plant and Equipment
Cost	15,104	14,948
Accumulated depreciation and amortization	(4,759)	(4,662)
Net property, plant and equipment	10,345	10,286
Other Noncurrent Assets
Regulatory assets	976	978
Other	234	189
Total other noncurrent assets	1,210	1,167
Total Assets	12,378	12,289
Current Liabilities
Accounts payable	157	196
Accounts payable to affiliated companies	73	78
Notes payable to affiliated companies	149	161
Taxes accrued	94	95
Interest accrued	52	57
Current maturities of long-term debt	62	3
Asset retirement obligations	65	54
Regulatory liabilities	20	24
Other	83	104
Total current liabilities	755	772
Long-Term Debt	3,570	3,630
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	941	925
Asset retirement obligations	713	727
Regulatory liabilities	1,743	1,723
Accrued pension and other post-retirement benefit costs	110	76
Investment tax credits	147	147
Other	28	18
Total other noncurrent liabilities	3,682	3,616
Commitments and Contingencies
Equity
Total member's equity	4,221	4,121
Total Liabilities and Equity	12,378	12,289
Piedmont Natural Gas [Member]
Current Assets
Cash and cash equivalents	12	19
Receivables (net of allowance for doubtful accounts)	251	275
Receivables from affiliated companies	7	7
Inventory	29	66
Regulatory assets	48	95
Other	21	52
Total current assets	368	514
Property, Plant and Equipment
Cost	6,861	6,725
Accumulated depreciation and amortization	(1,500)	(1,479)
Net property, plant and equipment	5,361	5,246
Other Noncurrent Assets
Goodwill	49	49
Regulatory assets	274	283
Investments in equity method unconsolidated affiliates	62	61
Other	66	65
Total other noncurrent assets	451	458
Total Assets	6,180	6,218
Current Liabilities
Accounts payable	128	125
Accounts payable to affiliated companies	32	13
Notes payable to affiliated companies	107	364
Taxes accrued	65	19
Interest accrued	24	31
Current maturities of long-term debt	250	250
Regulatory liabilities	45	3
Other	55	69
Total current liabilities	706	874
Long-Term Debt	1,787	1,787
Other Noncurrent Liabilities
Deferred income taxes	558	564
Asset retirement obligations	15	15
Regulatory liabilities	1,179	1,141
Accrued pension and other post-retirement benefit costs	4	5
Other	159	170
Total other noncurrent liabilities	1,915	1,895
Commitments and Contingencies
Equity
Common stock	860	860
Retained earnings	912	802
Total Parent stockholders' equity	1,772	1,662
Total Liabilities and Equity	$ 6,180	$ 6,218