Duke Energy (DUK) 10-K 24 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Entity Registrant Name	Duke Energy Corporation
Entity Central Index Key	1,326,160
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		699,607,929
Entity Public Float			$ 59,060,642,963
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Duke Energy Carolinas [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Carolinas, LLC
Entity Central Index Key	30,371
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Progress Energy [Member]
Document Information [Line Items]
Entity Registrant Name	Progress Energy, Inc.
Entity Central Index Key	1,094,093
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Duke Energy Progress [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Progress, LLC
Entity Central Index Key	17,797
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Duke Energy Florida [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Florida, LLC
Entity Central Index Key	37,637
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Duke Energy Ohio [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Ohio, Inc.
Entity Central Index Key	20,290
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Duke Energy Indiana [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Indiana, LLC
Entity Central Index Key	81,020
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	Yes

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Revenues [Abstract]
Regulated electric	$ 21,221	$ 21,379	$ 21,550
Nonregulated electric and other	659	456	386
Regulated natural gas	863	536	573
Total operating revenues	22,743	22,371	22,509
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	6,625	7,355	7,732
Cost of natural gas	265	141	185
Operation, maintenance and other	6,085	5,539	5,506
Depreciation and amortization	3,294	3,053	2,969
Property and other taxes	1,142	1,129	1,204
Impairment charges	18	106	81
Total operating expenses	17,429	17,323	17,677
Gains (Losses) on Sales of Other Assets and Other, net	27	30	10
Operating Income	5,341	5,078	4,842
Other Income and Expenses [Abstract]
Equity in earnings (losses) of unconsolidated affiliates	(15)	69	130
Other income and expenses, net	324	290	320
Total other income and expenses	309	359	450
Interest Expense	1,916	1,527	1,529
Income From Continuing Operations Before Income Taxes	3,734	3,910	3,763
Income Tax Expense from Continuing Operations	1,156	1,256	1,225
Income from Continuing Operations	2,578	2,654	2,538
(Loss) Income from discontinued operations	(408)	177	(649)
Net Income	2,170	2,831	1,889
Less: Net Income Attributable to Noncontrolling Interests	18	15	6
Net Income Attributable to Parent	2,152	2,816	1,883
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and OPEB adjustments	(11)	(13)	4
Reclassification into earnings from cash flow hedges	13	9	7
Unrealized gain (loss) on investments in available for sale securities	2	(6)	3
Other comprehensive income (loss), net of tax	715	(274)	(136)
Comprehensive Income (Loss)	2,885	2,557	1,753
Less: Comprehensive Income Attributable to Noncontrolling Interests	20	4	14
Comprehensive income (loss)	$ 2,865	$ 2,553	$ 1,739
Income From Continuing Operations Attributable To Parent Common Shareholders [Abstract]
Basic	$ 3.71	$ 3.80	$ 3.58
Diluted	3.71	3.80	3.58
Income (loss) from discontinued operations attributable To Duke Energy Corporation common shareholders [Abstract]
Basic	(0.60)	0.25	(0.92)
Diluted	(0.60)	0.25	(0.92)
Net income attributable to Duke Energy Corporation common shareholders [Abstract]
Basic	3.11	4.05	2.66
Diluted	$ 3.11	$ 4.05	$ 2.66
Weighted-average shares outstanding [Abstract]
Basic	691	694	707
Diluted	691	694	707
Duke Energy Carolinas [Member]
Operating Revenues [Abstract]
Total operating revenues	$ 7,322	$ 7,229	$ 7,351
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	1,797	1,881	2,133
Operation, maintenance and other	2,106	2,066	1,995
Depreciation and amortization	1,075	1,051	1,009
Property and other taxes	276	269	316
Impairment charges	1	1	3
Total operating expenses	5,255	5,268	5,456
Gains (Losses) on Sales of Other Assets and Other, net	(5)	(1)
Operating Income	2,062	1,960	1,895
Other Income and Expenses [Abstract]
Other income and expenses, net	162	160	172
Interest Expense	424	412	407
Income From Continuing Operations Before Income Taxes	1,800	1,708	1,660
Income Tax Expense from Continuing Operations	634	627	588
Net Income Attributable to Parent	1,166	1,081	1,072
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification into earnings from cash flow hedges	2	1	2
Unrealized gain (loss) on investments in available for sale securities		1
Other comprehensive income (loss), net of tax	2	2	2
Comprehensive income (loss)	1,168	1,083	1,074
Progress Energy [Member]
Operating Revenues [Abstract]
Total operating revenues	9,853	10,277	10,166
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	3,644	4,224	4,195
Operation, maintenance and other	2,386	2,298	2,335
Depreciation and amortization	1,213	1,116	1,128
Property and other taxes	487	492	517
Impairment charges	7	12	(16)
Total operating expenses	7,737	8,142	8,159
Gains (Losses) on Sales of Other Assets and Other, net	25	25	11
Operating Income	2,141	2,160	2,018
Other Income and Expenses [Abstract]
Other income and expenses, net	114	97	77
Interest Expense	689	670	675
Income From Continuing Operations Before Income Taxes	1,566	1,587	1,420
Income Tax Expense from Continuing Operations	527	522	540
Income from Continuing Operations	1,039	1,065	880
(Loss) Income from discontinued operations	2	(3)	(6)
Net Income	1,041	1,062	874
Less: Net Income Attributable to Noncontrolling Interests	10	11	5
Net Income Attributable to Parent	1,031	1,051	869
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and OPEB adjustments	1	(10)	9
Reclassification into earnings from cash flow hedges	8	4	8
Unrealized gain (loss) on investments in available for sale securities	1	(1)	1
Other comprehensive income (loss), net of tax	10	(7)	18
Comprehensive Income (Loss)	1,051	1,055	892
Less: Comprehensive Income Attributable to Noncontrolling Interests	10	11	5
Comprehensive income (loss)	1,041	1,044	887
Duke Energy Progress [Member]
Operating Revenues [Abstract]
Total operating revenues	5,277	5,290	5,176
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	1,830	2,029	2,036
Operation, maintenance and other	1,504	1,452	1,470
Depreciation and amortization	703	643	582
Property and other taxes	156	140	174
Impairment charges	1	5	(18)
Total operating expenses	4,194	4,269	4,244
Gains (Losses) on Sales of Other Assets and Other, net	3	3	3
Operating Income	1,086	1,024	935
Other Income and Expenses [Abstract]
Other income and expenses, net	71	71	51
Interest Expense	257	235	234
Income From Continuing Operations Before Income Taxes	900	860	752
Income Tax Expense from Continuing Operations	301	294	285
Net Income Attributable to Parent	599	566	467
Duke Energy Florida [Member]
Operating Revenues [Abstract]
Total operating revenues	4,568	4,977	4,975
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	1,814	2,195	2,158
Operation, maintenance and other	865	835	850
Depreciation and amortization	509	473	545
Property and other taxes	333	352	343
Impairment charges	6	7	2
Total operating expenses	3,527	3,862	3,898
Gains (Losses) on Sales of Other Assets and Other, net			1
Operating Income	1,041	1,115	1,078
Other Income and Expenses [Abstract]
Other income and expenses, net	44	24	20
Interest Expense	212	198	201
Income From Continuing Operations Before Income Taxes	873	941	897
Income Tax Expense from Continuing Operations	322	342	349
Net Income Attributable to Parent	551	599	548
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification into earnings from cash flow hedges			1
Unrealized gain (loss) on investments in available for sale securities	1
Other comprehensive income (loss), net of tax	1	0	1
Comprehensive income (loss)	552	599	549
Duke Energy Ohio [Member]
Operating Revenues [Abstract]
Regulated electric	1,410	1,331	1,316
Nonregulated electric and other	31	33	19
Regulated natural gas	503	541	578
Total operating revenues	1,944	1,905	1,913
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	442	446	459
Fuel used in electric generation and purchased power - nonregulated	51	47	25
Cost of natural gas	103	141	185
Operation, maintenance and other	512	495	516
Depreciation and amortization	233	227	214
Property and other taxes	258	254	234
Impairment charges			94
Total operating expenses	1,599	1,610	1,727
Gains (Losses) on Sales of Other Assets and Other, net	2	8	1
Operating Income	347	303	187
Other Income and Expenses [Abstract]
Other income and expenses, net	9	6	10
Interest Expense	86	79	86
Income From Continuing Operations Before Income Taxes	270	230	111
Income Tax Expense from Continuing Operations	78	81	43
Income from Continuing Operations	192	149	68
(Loss) Income from discontinued operations	36	23	(563)
Net Income Attributable to Parent	228	172	(495)
Duke Energy Indiana [Member]
Operating Revenues [Abstract]
Total operating revenues	2,958	2,890	3,175
Operating Expenses [Abstract]
Fuel used in electric generation and purchased power	909	982	1,259
Operation, maintenance and other	723	682	670
Depreciation and amortization	496	434	413
Property and other taxes	58	61	128
Impairment charges	8	88
Total operating expenses	2,194	2,247	2,470
Gains (Losses) on Sales of Other Assets and Other, net	1	1
Operating Income	765	644	705
Other Income and Expenses [Abstract]
Other income and expenses, net	22	11	22
Interest Expense	181	176	171
Income From Continuing Operations Before Income Taxes	606	479	556
Income Tax Expense from Continuing Operations	225	163	197
Net Income Attributable to Parent	381	316	359
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification into earnings from cash flow hedges	(1)	(2)
Other comprehensive income (loss), net of tax	(1)	(2)
Comprehensive income (loss)	$ 380	$ 314	$ 359

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 2,170	$ 2,831	$ 1,889
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments		694	(264)	(124)
Pension and OPEB adjustments		(11)	(13)	4
Net unrealized gain (loss) on cash flow hedges	[1]	17		(26)
Reclassification into earnings from cash flow hedges		13	9	7
Unrealized gain (loss) on investments in available for sale securities		2	(6)	3
Other comprehensive income (loss), net of tax		715	(274)	(136)
Comprehensive Income		2,885	2,557	1,753
Less: Comprehensive Income Attributable to Noncontrolling Interests		20	4	14
Comprehensive income (loss)		$ 2,865	$ 2,553	$ 1,739
[1]	Net of insignificant tax expense in 2016 and 2015, and $13 million tax benefit in 2014.

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parenthetical) (Parentheticals) $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ 13

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current Assets [Abstract]
Cash and cash equivalents	$ 392	$ 383
Receivables (net of allowance for doubtful accounts)	751	515
Receivables of VIEs (net of allowance for doubtful accounts)	1,893	1,748
Inventory	3,522	3,746
Assets held for sale		746
Regulatory assets	1,023	877
Other	458	307
Total current assets	8,039	8,322
Investments and Other Assets [Abstract]
Investments in equity method unconsolidated affiliates	925	499
Nuclear decommissioning trust funds	6,205	5,825
Goodwill	19,425	16,072
Assets held for sale		2,413
Other	2,752	2,830
Total investments and other assets	29,307	27,639
Property, Plant and Equipment [Abstract]
Cost	121,397	109,967
Accumulated depreciation and amortization	(39,406)	(36,736)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	82,520	73,779
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	12,878	11,373
Other	17	43
Total regulatory assets and deferred debits	12,895	11,416
Total Assets	132,761	121,156
Current Liabilities [Abstract]
Accounts payable	2,994	2,350
Notes payable and commercial paper	2,487	3,633
Taxes accrued	384	289
Interest accrued	503	412
Current maturities of long-term debt	2,319	2,026
Liabilities associated with assets held for sale		279
Asset retirement obligations	411
Regulatory liabilities	409	400
Other	2,044	2,011
Total current liabilities	11,551	11,400
Long-Term Debt	45,576	36,842
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	14,155	12,548
Investment tax credits	493	472
Accrued pension and other post-retirement benefit costs	1,111	1,088
Liabilities associated with assets held for sale		900
Asset retirement obligations	10,200	10,249
Regulatory liabilities	6,881	6,255
Other	1,753	1,631
Total deferred credits and other liabilities	34,593	33,143
Commitments and Contingencies
Equity [Abstract]
Common stock	1	1
Additional paid-in capital	38,741	37,968
Retained earnings	2,384	2,564
Accumulated other comprehensive (loss) income	(93)	(806)
Total Duke Energy Corporation stockholders' equity	41,033	39,727
Noncontrolling interests	8	44
Total equity	41,041	39,771
Total Liabilities and Equity	132,761	121,156
Duke Energy Carolinas [Member]
Current Assets [Abstract]
Cash and cash equivalents	14	13
Receivables (net of allowance for doubtful accounts)	160	142
Receivables of VIEs (net of allowance for doubtful accounts)	645	596
Receivables from affiliated companies	163	107
Notes receivable from affiliated companies	66	163
Inventory	1,055	1,276
Regulatory assets	238	305
Other	37	128
Total current assets	2,378	2,730
Investments and Other Assets [Abstract]
Nuclear decommissioning trust funds	3,273	3,050
Other	940	999
Total investments and other assets	4,213	4,049
Property, Plant and Equipment [Abstract]
Cost	41,127	39,398
Accumulated depreciation and amortization	(14,365)	(13,521)
Net property, plant and equipment	26,762	25,877
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	3,159	2,766
Other	3	4
Total regulatory assets and deferred debits	3,162	2,770
Total Assets	36,515	35,426
Current Liabilities [Abstract]
Accounts payable	833	753
Accounts payable to affiliated companies	247	229
Taxes accrued	143	25
Interest accrued	102	95
Current maturities of long-term debt	116	356
Asset retirement obligations	222
Regulatory liabilities	161	39
Other	468	519
Total current liabilities	2,292	2,016
Long-Term Debt	9,187	7,711
Long-Term Debt Payable to Affiliated Companies	300	300
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	6,544	6,146
Investment tax credits	203	199
Accrued pension and other post-retirement benefit costs	97	107
Asset retirement obligations	3,673	3,918
Regulatory liabilities	2,840	2,802
Other	607	621
Total deferred credits and other liabilities	13,964	13,793
Commitments and Contingencies
Equity [Abstract]
Members' Equity	10,781	11,617
Accumulated other comprehensive (loss) income	(9)	(11)
Total equity	10,772	11,606
Total Liabilities and Equity	36,515	35,426
Progress Energy [Member]
Current Assets [Abstract]
Cash and cash equivalents	46	44
Receivables (net of allowance for doubtful accounts)	114	151
Receivables of VIEs (net of allowance for doubtful accounts)	692	658
Receivables from affiliated companies	106	375
Notes receivable from affiliated companies	80
Inventory	1,717	1,751
Regulatory assets	401	362
Other	148	156
Total current assets	3,304	3,497
Investments and Other Assets [Abstract]
Nuclear decommissioning trust funds	2,932	2,775
Goodwill	3,655	3,655
Other	852	834
Total investments and other assets	7,439	7,264
Property, Plant and Equipment [Abstract]
Cost	44,864	42,666
Accumulated depreciation and amortization	(15,212)	(14,867)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	30,181	28,347
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	5,722	5,435
Other	4	5
Total regulatory assets and deferred debits	5,726	5,440
Total Assets	46,650	44,548
Current Liabilities [Abstract]
Accounts payable	1,003	722
Accounts payable to affiliated companies	348	311
Notes payable to affiliated companies	729	1,308
Taxes accrued	83	53
Interest accrued	201	195
Current maturities of long-term debt	778	315
Asset retirement obligations	189
Regulatory liabilities	189	286
Other	745	891
Total current liabilities	4,265	4,081
Long-Term Debt	15,590	13,999
Long-Term Debt Payable to Affiliated Companies	1,173	150
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	5,246	4,790
Accrued pension and other post-retirement benefit costs	547	536
Asset retirement obligations	5,286	5,369
Regulatory liabilities	2,395	2,387
Other	341	383
Total deferred credits and other liabilities	13,815	13,465
Commitments and Contingencies
Equity [Abstract]
Additional paid-in capital	8,094	8,092
Retained earnings	3,764	4,831
Accumulated other comprehensive (loss) income	(38)	(48)
Total Duke Energy Corporation stockholders' equity	11,820	12,875
Noncontrolling interests	(13)	(22)
Total equity	11,807	12,853
Total Liabilities and Equity	46,650	44,548
Duke Energy Progress [Member]
Current Assets [Abstract]
Cash and cash equivalents	11	15
Receivables (net of allowance for doubtful accounts)	51	87
Receivables of VIEs (net of allowance for doubtful accounts)	404	349
Receivables from affiliated companies	5	16
Notes receivable from affiliated companies	165
Inventory	1,076	1,088
Regulatory assets	188	264
Other	57	121
Total current assets	1,957	1,940
Investments and Other Assets [Abstract]
Nuclear decommissioning trust funds	2,217	2,035
Other	523	486
Total investments and other assets	2,740	2,521
Property, Plant and Equipment [Abstract]
Cost	28,419	27,313
Accumulated depreciation and amortization	(10,561)	(10,141)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	18,387	17,720
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	3,243	2,710
Other	2	3
Total regulatory assets and deferred debits	3,245	2,713
Total Assets	26,329	24,894
Current Liabilities [Abstract]
Accounts payable	589	399
Accounts payable to affiliated companies	227	190
Notes payable to affiliated companies	0	209
Taxes accrued	104	15
Interest accrued	102	96
Current maturities of long-term debt	452	2
Asset retirement obligations	189
Regulatory liabilities	158	85
Other	365	412
Total current liabilities	2,186	1,408
Long-Term Debt	6,409	6,366
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	3,323	3,027
Investment tax credits	146	132
Accrued pension and other post-retirement benefit costs	252	262
Asset retirement obligations	4,508	4,567
Regulatory liabilities	1,946	1,878
Other	51	45
Total deferred credits and other liabilities	10,226	9,911
Equity [Abstract]
Total equity	7,358	7,059
Total Liabilities and Equity	26,329	24,894
Duke Energy Florida [Member]
Current Assets [Abstract]
Cash and cash equivalents	16	8
Receivables (net of allowance for doubtful accounts)	61	60
Receivables of VIEs (net of allowance for doubtful accounts)	288	308
Receivables from affiliated companies	5	84
Inventory	641	663
Regulatory assets	213	98
Other	125	21
Total current assets	1,349	1,242
Investments and Other Assets [Abstract]
Nuclear decommissioning trust funds	715	740
Other	276	292
Total investments and other assets	991	1,032
Property, Plant and Equipment [Abstract]
Cost	16,434	15,343
Accumulated depreciation and amortization	(4,644)	(4,720)
Net property, plant and equipment	11,790	10,623
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	2,480	2,725
Other	2	2
Total regulatory assets and deferred debits	2,482	2,727
Total Assets	16,612	15,624
Current Liabilities [Abstract]
Accounts payable	413	322
Accounts payable to affiliated companies	125	116
Notes payable to affiliated companies	297	813
Taxes accrued	33	132
Interest accrued	49	43
Current maturities of long-term debt	326	13
Regulatory liabilities	31	200
Other	352	452
Total current liabilities	1,626	2,091
Long-Term Debt	5,799	4,253
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	2,694	2,460
Accrued pension and other post-retirement benefit costs	262	242
Asset retirement obligations	778	802
Regulatory liabilities	448	509
Other	105	146
Total deferred credits and other liabilities	4,287	4,159
Equity [Abstract]
Members' Equity	4,899	5,121
Accumulated other comprehensive (loss) income	1
Total equity	4,900	5,121
Total Liabilities and Equity	16,612	15,624
Duke Energy Ohio [Member]
Current Assets [Abstract]
Cash and cash equivalents	13	14
Receivables (net of allowance for doubtful accounts)	71	66
Receivables from affiliated companies	129	84
Notes receivable from affiliated companies	94
Inventory	137	105
Regulatory assets	37	36
Other	37	110
Total current assets	518	415
Investments and Other Assets [Abstract]
Goodwill	920	920
Other	21	20
Total investments and other assets	941	940
Property, Plant and Equipment [Abstract]
Cost	8,126	7,750
Accumulated depreciation and amortization	(2,579)	(2,507)
Net property, plant and equipment	5,547	5,243
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	520	497
Other	2	2
Total regulatory assets and deferred debits	522	499
Total Assets	7,528	7,097
Current Liabilities [Abstract]
Accounts payable	282	207
Accounts payable to affiliated companies	63	53
Notes payable to affiliated companies	16	103
Taxes accrued	178	171
Interest accrued	19	18
Current maturities of long-term debt	1	106
Regulatory liabilities	21	12
Other	91	153
Total current liabilities	671	823
Long-Term Debt	1,858	1,467
Long-Term Debt Payable to Affiliated Companies	25	25
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	1,443	1,407
Accrued pension and other post-retirement benefit costs	56	56
Asset retirement obligations	77	125
Regulatory liabilities	236	245
Other	166	165
Total deferred credits and other liabilities	1,978	1,998
Equity [Abstract]
Common stock	762	762
Additional paid-in capital	2,695	2,720
Retained earnings	(461)	(698)
Total equity	2,996	2,784
Total Liabilities and Equity	7,528	7,097
Duke Energy Indiana [Member]
Current Assets [Abstract]
Cash and cash equivalents	17	9
Receivables (net of allowance for doubtful accounts)	105	96
Receivables from affiliated companies	114	71
Notes receivable from affiliated companies	86	83
Inventory	504	570
Regulatory assets	149	102
Other	45	15
Total current assets	1,020	946
Investments and Other Assets [Abstract]
Total investments and other assets	145	212
Property, Plant and Equipment [Abstract]
Cost	14,241	14,007
Accumulated depreciation and amortization	(4,317)	(4,484)
Net property, plant and equipment	9,924	9,523
Regulatory Assets and Deferred Debits [Abstract]
Regulatory assets	1,073	716
Other	2	2
Total regulatory assets and deferred debits	1,075	718
Total Assets	12,164	11,399
Current Liabilities [Abstract]
Accounts payable	263	189
Accounts payable to affiliated companies	74	83
Notes payable to affiliated companies		0
Taxes accrued	31	89
Interest accrued	61	56
Current maturities of long-term debt	3	547
Regulatory liabilities	40	62
Other	93	97
Total current liabilities	565	1,123
Long-Term Debt	3,633	3,071
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities [Abstract]
Deferred income taxes	1,900	1,657
Investment tax credits	137	138
Accrued pension and other post-retirement benefit costs	71	80
Asset retirement obligations	866	525
Regulatory liabilities	748	754
Other	27	65
Total deferred credits and other liabilities	3,749	3,219
Equity [Abstract]
Members' Equity	4,067
Common stock		1
Additional paid-in capital		1,384
Retained earnings		2,450
Accumulated other comprehensive (loss) income		1
Total equity	4,067
Total equity		3,836
Total Liabilities and Equity	$ 12,164	$ 11,399

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Receivables (net of allowance for doubtful accounts)	$ 14	$ 12
Receivables of VIEs (net of allowance for doubtful accounts)	54	53
Regulatory assets	1,023	877
Other	458	307
Regulatory assets	12,878	11,373
Current maturities of long-term debt	2,319	2,026
Long-Term Debt	$ 45,576	$ 36,842
Common stock, par or stated value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	700,000,000	688,000,000
Duke Energy Carolinas [Member]
Receivables (net of allowance for doubtful accounts)	$ 2	$ 3
Receivables of VIEs (net of allowance for doubtful accounts)	7	7
Regulatory assets	238	305
Other	37	128
Regulatory assets	3,159	2,766
Current maturities of long-term debt	116	356
Long-Term Debt	9,187	7,711
Progress Energy [Member]
Receivables (net of allowance for doubtful accounts)	6	6
Receivables of VIEs (net of allowance for doubtful accounts)	7	8
Regulatory assets	401	362
Other	148	156
Regulatory assets	5,722	5,435
Current maturities of long-term debt	778	315
Long-Term Debt	$ 15,590	$ 13,999
Common stock, par or stated value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares outstanding	100,000,000	100,000,000
Duke Energy Progress [Member]
Receivables (net of allowance for doubtful accounts)	$ 4	$ 4
Receivables of VIEs (net of allowance for doubtful accounts)	5	5
Regulatory assets	188	264
Other	57	121
Regulatory assets	3,243	2,710
Current maturities of long-term debt	452	2
Long-Term Debt	6,409	6,366
Duke Energy Florida [Member]
Receivables (net of allowance for doubtful accounts)	2	2
Receivables of VIEs (net of allowance for doubtful accounts)	2	3
Regulatory assets	213	98
Other	125	21
Regulatory assets	2,480	2,725
Current maturities of long-term debt	326	13
Long-Term Debt	5,799	4,253
Duke Energy Ohio [Member]
Receivables (net of allowance for doubtful accounts)	2	2
Regulatory assets	37	36
Other	37	110
Regulatory assets	520	497
Current maturities of long-term debt	1	106
Long-Term Debt	$ 1,858	$ 1,467
Common stock, par or stated value	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	89,663,086	89,663,086
Duke Energy Indiana [Member]
Receivables (net of allowance for doubtful accounts)	$ 1	$ 1
Regulatory assets	149	102
Other	45	15
Regulatory assets	1,073	716
Current maturities of long-term debt	3	547
Long-Term Debt	$ 3,633	$ 3,071
Common stock, par or stated value	$ 0.01	$ 0.01
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares outstanding	53,913,701	53,913,701
Variable Interest Entity [Member]
Regulatory assets	$ 50
Regulatory assets	1,142
Current maturities of long-term debt	260	$ 125
Long-Term Debt	3,587	2,197
Variable Interest Entity [Member] | Progress Energy [Member]
Regulatory assets	50
Regulatory assets	1,142
Current maturities of long-term debt	62
Long-Term Debt	1,741	479
Variable Interest Entity [Member] | Duke Energy Florida [Member]
Regulatory assets	50
Other	53
Regulatory assets	1,142
Current maturities of long-term debt	62
Long-Term Debt	$ 1,442	$ 225

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss)	$ 2,170	$ 2,831	$ 1,889
Net Income (Loss) Attributable to Parent	2,152	2,816	1,883
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	3,880	3,613	3,507
Equity component of AFUDC	(200)	(164)	(135)
FERC mitigation costs			(15)
Accrued charitable contributions related to Piedmont commitments	93
Losses (gains) on sales of other assets	477	(48)	(33)
Impairment charges	212	153	915
Deferred income taxes	900	1,244	1,149
Equity in earnings of unconsolidated affiliates	15	(69)	(130)
Accrued pension and other post-retirement benefit costs	21	71	108
Contributions to qualified pension plans	(155)	(302)
Payments for asset retirement obligations	(608)	(346)	(68)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	34	(29)	44
Receivables	(391)	359	58
Inventory	272	(237)	(269)
Other current assets	(220)	(65)	(414)
Increase (decrease) in [Abstract]
Accounts payable	266	(6)	(30)
Taxes accrued	236	(38)	(14)
Other current liabilities	182	168	(201)
Other assets	(186)	(216)	16
Other liabilities	(200)	(243)	209
Net cash provided by operating activities	6,798	6,676	6,586
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(7,901)	(6,766)	(5,384)
Investment expenditures	(307)	(263)	(90)
Acquisitions, net of cash acquired	(4,778)	(1,334)	(54)
Purchases of available-for-sale securities	(5,153)	(4,037)	(4,110)
Proceeds from sales and maturities of available-for-sale securities	5,236	4,040	4,133
Proceeds from the sales of discontinued operations and other assets, net of cash divested	1,418	2,968	179
Change in Restricted Cash	(4)	191	9
Other	(44)	(76)	(56)
Net cash used in investing activities	(11,533)	(5,277)	(5,373)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	9,238	2,955	2,914
Proceeds from Issuance of Common Stock	731
Proceeds from the issuance of common stock		17	25
Payments for the redemption of long-term debt	(1,923)	(3,029)	(3,037)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	2,081	379	1,066
Payments for the redemption of short-term debt with original maturities greater than 90 days	(2,166)	(931)	(564)
Notes payable and commercial paper	(1,362)	1,797	1,186
Distributions to noncontrolling interests	(6)	(9)	(65)
Dividends paid	(2,332)	(2,254)	(2,234)
Repurchase of common shares		(1,500)
Other	9	(3)	31
Net cash provided by (used in) financing activities	4,270	(2,578)	(678)
Changes in Cash and Cash Equivalents included in asses held for sale	474	1,099	(548)
Net increase (decrease) in cash and cash equivalents	9	(80)	(13)
Cash and cash equivalents at beginning of period	383	463	476
Cash and cash equivalents at end of period	392	383	463
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	1,794	1,607	1,659
Cash paid for (received from) income taxes	229	170	158
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	1,000	771	664
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss) Attributable to Parent	1,166	1,081	1,072
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,382	1,361	1,273
Equity component of AFUDC	(102)	(96)	(91)
FERC mitigation costs			3
Accrued charitable contributions related to Piedmont commitments	52
Losses (gains) on sales of other assets	5	1
Impairment charges	1	1
Deferred income taxes	470	397	376
Accrued pension and other post-retirement benefit costs	4	15	22
Contributions to qualified pension plans	(43)	(91)
Payments for asset retirement obligations	(287)	(167)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	5
Receivables	(76)	42	48
Receivables from affiliated companies	(56)	(32)
Inventory	215	(157)	(60)
Other current assets	67	(51)	(236)
Increase (decrease) in [Abstract]
Accounts payable	(85)	(4)	10
Accounts payable to affiliated companies	18	75	(7)
Taxes accrued	187	(128)	(15)
Other current liabilities	63	127	(10)
Other assets	20	76	17
Other liabilities	(30)	(77)	(22)
Net cash provided by operating activities	2,976	2,373	2,380
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(2,220)	(1,933)	(1,879)
Purchases of available-for-sale securities	(2,832)	(2,555)	(2,064)
Proceeds from sales and maturities of available-for-sale securities	2,832	2,555	2,044
Notes receivable from affiliated companies		(13)
Notes receivable from affiliated companies	97		72
Other	(83)	(35)	(18)
Net cash used in investing activities	(2,206)	(1,981)	(1,845)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	1,587	516
Payments for the redemption of long-term debt	(356)	(506)	(45)
Distributions to parent	(2,000)	(401)	(500)
Other		(1)
Net cash provided by (used in) financing activities	(769)	(392)	(545)
Net increase (decrease) in cash and cash equivalents	1		(10)
Cash and cash equivalents at beginning of period	13	13	23
Cash and cash equivalents at end of period	14	13	13
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	393	389	388
Cash paid for (received from) income taxes	(60)	342	305
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	347	239	194
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss)	1,041	1,062	874
Net Income (Loss) Attributable to Parent	1,031	1,051	869
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,435	1,312	1,313
Equity component of AFUDC	(76)	(54)	(26)
FERC mitigation costs			(18)
Accrued charitable contributions related to Piedmont commitments	32
Losses (gains) on sales of other assets	(34)	(31)	(6)
Impairment charges	7	12	2
Deferred income taxes	532	714	1,014
Accrued pension and other post-retirement benefit costs	(24)	(5)	27
Contributions to qualified pension plans	(43)	(83)
Payments for asset retirement obligations	(270)	(156)	(68)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	42	(6)	12
Receivables	7	105	(31)
Receivables from affiliated companies	211	(316)	(56)
Inventory	35	(67)	(101)
Other current assets	3	553	(934)
Increase (decrease) in [Abstract]
Accounts payable	242	(193)	6
Accounts payable to affiliated companies	37	108	80
Taxes accrued	15	(63)	(20)
Other current liabilities	(42)	136	(144)
Other assets	(248)	(167)	(14)
Other liabilities	(58)	(112)	56
Net cash provided by operating activities	2,844	2,749	1,966
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(3,306)	(2,698)	(1,940)
Acquisitions	(10)	(1,249)
Purchases of available-for-sale securities	(2,143)	(1,174)	(1,689)
Proceeds from sales and maturities of available-for-sale securities	2,187	1,211	1,652
Proceeds from Insurance	58
Proceeds from the sale of nuclear fuel	20	102
Notes receivable from affiliated companies	(80)		(145)
Notes receivable from affiliated companies		220
Change in Restricted Cash	(6)
Other	47	(34)	(44)
Net cash used in investing activities	(3,233)	(3,622)	(2,166)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	2,375	1,186	1,572
Payments for the redemption of long-term debt	(327)	(1,553)	(931)
Notes payable to affiliated companies	444	623	(378)
Distributions to noncontrolling interests	(1)	(4)	(37)
Capital contribution from parent		625
Dividends to parent	(2,098)
Other	(2)	(2)	(42)
Net cash provided by (used in) financing activities	391	875	184
Net increase (decrease) in cash and cash equivalents	2	2	(16)
Cash and cash equivalents at beginning of period	44	42	58
Cash and cash equivalents at end of period	46	44	42
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	673	649	664
Cash paid for (received from) income taxes	(187)	(426)	141
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	317	329	294
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss) Attributable to Parent	599	566	467
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	907	821	761
Equity component of AFUDC	(50)	(47)	(25)
FERC mitigation costs			(18)
Accrued charitable contributions related to Piedmont commitments	32
Losses (gains) on sales of other assets	(6)	(7)	(3)
Impairment charges	1	5
Deferred income taxes	384	354	455
Accrued pension and other post-retirement benefit costs	(32)	(14)	(7)
Contributions to qualified pension plans	(24)	(42)
Payments for asset retirement obligations	(212)	(109)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	4	(3)	13
Receivables	(17)	43	78
Receivables from affiliated companies	11	(6)	(8)
Inventory	12	(50)	(65)
Other current assets	84	185	(416)
Increase (decrease) in [Abstract]
Accounts payable	171	(65)	27
Accounts payable to affiliated companies	37	70	17
Taxes accrued	90	(34)	10
Other current liabilities	114	76	(68)
Other assets	(163)	(83)	48
Other liabilities	(10)	(66)	(21)
Net cash provided by operating activities	1,932	1,594	1,245
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(1,733)	(1,669)	(1,241)
Acquisitions		(1,249)
Purchases of available-for-sale securities	(1,658)	(727)	(499)
Proceeds from sales and maturities of available-for-sale securities	1,615	672	458
Notes receivable from affiliated companies	(165)		(237)
Notes receivable from affiliated companies		237
Other	26	(30)	(12)
Net cash used in investing activities	(1,915)	(2,766)	(1,531)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	505	1,186	1,347
Payments for the redemption of long-term debt	(15)	(991)	(379)
Notes payable to affiliated companies	(209)	359	(462)
Capital contribution from parent		626
Dividends to parent			(225)
Distributions to parent	(300)
Other	(2)	(2)	(7)
Net cash provided by (used in) financing activities	(21)	1,178	274
Net increase (decrease) in cash and cash equivalents	(4)	6	(12)
Cash and cash equivalents at beginning of period	15	9	21
Cash and cash equivalents at end of period	11	15	9
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	248	218	220
Cash paid for (received from) income taxes	(287)	(197)	81
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	147	143	194
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss) Attributable to Parent	551	599	548
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	516	480	550
Equity component of AFUDC	(26)	(7)
Losses (gains) on sales of other assets			(1)
Impairment charges	6	7	2
Deferred income taxes	224	348	400
Accrued pension and other post-retirement benefit costs	2	5	29
Contributions to qualified pension plans	(20)	(40)
Payments for asset retirement obligations	(58)	(47)	(68)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	38	(3)	(9)
Receivables	23	61	(33)
Receivables from affiliated companies	21	(44)	(37)
Inventory	23	(17)	(36)
Other current assets	(133)	116	(269)
Increase (decrease) in [Abstract]
Accounts payable	71	(127)	18
Accounts payable to affiliated companies	9	46	32
Taxes accrued	(117)	67	(31)
Other current liabilities	(149)	57	(80)
Other assets	(84)	(84)	(59)
Other liabilities	(53)	(44)	10
Net cash provided by operating activities	844	1,373	966
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(1,573)	(1,029)	(699)
Acquisitions	(10)
Purchases of available-for-sale securities	(485)	(447)	(1,189)
Proceeds from sales and maturities of available-for-sale securities	572	538	1,195
Proceeds from Insurance	58
Proceeds from the sale of nuclear fuel	20	102
Change in Restricted Cash	(6)
Other	21	(3)	(31)
Net cash used in investing activities	(1,403)	(839)	(724)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	1,870		225
Payments for the redemption of long-term debt	(12)	(562)	(252)
Notes payable to affiliated companies	(516)	729	(97)
Dividends to parent		(350)	(124)
Distributions to parent	(775)	(350)
Other		(1)	(2)
Net cash provided by (used in) financing activities	567	(534)	(250)
Net increase (decrease) in cash and cash equivalents	8		(8)
Cash and cash equivalents at beginning of period	8	8	16
Cash and cash equivalents at end of period	16	8	8
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	208	205	203
Cash paid for (received from) income taxes	216	(229)	59
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	170	186	100
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss) Attributable to Parent	228	172	(495)
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	237	230	258
Equity component of AFUDC	(6)	(3)	(4)
Losses (gains) on sales of other assets	(2)	(8)	(1)
Impairment charges		40	941
Deferred income taxes	55	206	(219)
Accrued pension and other post-retirement benefit costs	6	9	8
Contributions to qualified pension plans	(5)	(8)
Payments for asset retirement obligations	(5)	(4)
(Increase) decrease in [Abstract]
Net realized and unrealized mark-to-market and hedging transactions	(2)	(10)	27
Receivables	(4)	23	(56)
Receivables from affiliated companies	(36)	23	14
Inventory	(32)		8
Other current assets	79		(5)
Increase (decrease) in [Abstract]
Accounts payable	19	(1)	27
Accounts payable to affiliated companies	10	(21)	(3)
Taxes accrued	3	(21)	(9)
Other current liabilities	(54)	88	27
Other assets	(35)	25	(4)
Other liabilities	(31)	(73)	(33)
Net cash provided by operating activities	425	667	481
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(476)	(399)	(322)
Notes receivable from affiliated companies	(94)		(88)
Notes receivable from affiliated companies		145
Other	(30)	(15)	(12)
Net cash used in investing activities	(600)	(269)	(422)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	341
Payments for the redemption of long-term debt	(53)	(157)	(449)
Notes payable to affiliated companies	(87)	(95)	473
Capital contribution from parent	9
Dividends to parent	(25)	(150)	(100)
Other	(2)	(2)	1
Net cash provided by (used in) financing activities	174	(404)	(75)
Net increase (decrease) in cash and cash equivalents	(1)	(6)	(16)
Cash and cash equivalents at beginning of period	14	20	36
Cash and cash equivalents at end of period	13	14	20
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	81	76	76
Cash paid for (received from) income taxes	(46)	410	(5)
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	83	20	24
Distribution of membership interest of Duke Energy SAM, LLC to parent		1,912
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]
Net Income (Loss) Attributable to Parent	381	316	359
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
Depreciation, amortization and accretion (including amortization of nuclear fuel)	499	439	416
Equity component of AFUDC	(16)	(11)	(14)
Losses (gains) on sales of other assets		(1)
Impairment charges	8	88
Deferred income taxes	213	262	308
Accrued pension and other post-retirement benefit costs	8	13	16
Contributions to qualified pension plans	(9)	(19)
Payments for asset retirement obligations	(46)	(19)
(Increase) decrease in [Abstract]
Receivables	(2)	(7)	(35)
Receivables from affiliated companies	(43)	44	36
Inventory	66	(21)	(103)
Other current assets	(67)	90	(8)
Increase (decrease) in [Abstract]
Accounts payable	8	33	(41)
Accounts payable to affiliated companies	(9)	25	2
Taxes accrued	(4)	35	(32)
Other current liabilities	(81)	26	5
Other assets	(27)	(82)	(21)
Other liabilities	(8)	(35)	17
Net cash provided by operating activities	871	1,176	905
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]
Capital expenditures	(755)	(690)	(625)
Purchases of available-for-sale securities	(14)	(9)	(20)
Proceeds from sales and maturities of available-for-sale securities	11	11	16
Proceeds from the sales of discontinued operations and other assets, net of cash divested		17
Notes receivable from affiliated companies	(3)	(83)
Notes receivable from affiliated companies			96
Other	32	(17)	4
Net cash used in investing activities	(729)	(771)	(529)
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]
Proceeds from the issuance of long-term debt	494
Payments for the redemption of long-term debt	(478)	(5)	(5)
Notes payable to affiliated companies		(71)	71
Dividends to parent		(326)	(450)
Distributions to parent	(149)
Other	(1)		(1)
Net cash provided by (used in) financing activities	(134)	(402)	(385)
Net increase (decrease) in cash and cash equivalents	8	3	(9)
Cash and cash equivalents at beginning of period	9	6	15
Cash and cash equivalents at end of period	17	9	6
Supplemental Disclosures [Abstract]
Cash paid for interest, net of amount capitalized	171	175	169
Cash paid for (received from) income taxes	(7)	(253)	(61)
Significant Non-cash Transactions [Abstract]
Accrued capital expenditures	$ 99	$ 64	$ 87

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Foreign Currency Adjustments [Member]		Net Gains (Losses) on Cash Flow Hedges [Member]	Net Gains (Losses) on Available for Sale Securities [Member]	Pension And OPEB Related Adjustments To AOCI [Member]	Common Stockholders' Equity [Member]	Noncontrolling Interest [Member]		Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member]Members Equity [Member]	Duke Energy Carolinas [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Duke Energy Carolinas [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]	Progress Energy [Member]Additional Paid In Capital [Member]	Progress Energy [Member]Retained Earnings [Member]	Progress Energy [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]Pension And OPEB Related Adjustments To AOCI [Member]	Progress Energy [Member]Common Stockholders' Equity [Member]	Progress Energy [Member]Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Progress [Member]Common Stock [Member]	Duke Energy Progress [Member]Members Equity [Member]	Duke Energy Progress [Member]Retained Earnings [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]Common Stock [Member]	Duke Energy Florida [Member]Members Equity [Member]	Duke Energy Florida [Member]Retained Earnings [Member]	Duke Energy Florida [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Duke Energy Florida [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]Common Stock [Member]	Duke Energy Ohio [Member]Additional Paid In Capital [Member]	Duke Energy Ohio [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]Common Stock [Member]	Duke Energy Indiana [Member]Additional Paid In Capital [Member]	Duke Energy Indiana [Member]Members Equity [Member]	Duke Energy Indiana [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]Net Gains (Losses) on Cash Flow Hedges [Member]
Balance (in shares) at Dec. 31, 2013		706,000,000
Balance at Dec. 31, 2013	$ 41,408	$ 1	$ 39,365	$ 2,363	$ (307)		$ (40)		$ (52)	$ 41,330	$ 78						$ 10,864	$ 7,467	$ 3,452	$ (43)		$ (16)	$ 10,860	$ 4	$ 5,625	$ 2,159		$ 3,466	$ 4,797	$ 1,762		$ 3,036	$ (1)		$ 5,269	$ 762	$ 4,882	$ (375)	$ 3,939	$ 1	$ 1,384		$ 2,551	$ 3
Beginning member's equity at Dec. 31, 2013													$ 10,350	$ 10,365	$ (14)	$ (1)
Net Income (Loss)	1,889			1,883						1,883	6						874		869				869	5
Net Income (Loss) Attributable to Parent	1,883												1,072	1,072			869								467			467	548			548			(495)			(495)	359				359
Other comprehensive income (loss), net of tax	(136)				(132)		(19)	$ 3	4	(144)	8		2		2		18			8	$ 1	9	18						1				$ 1
Distribution to Parent													(500)	(500)
Common stock issuances, including dividend reinvestment and employee benefits (in shares)		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	40		40							40
Common stock dividends	(2,234)			(2,234)						(2,234)															(225)			(225)	(124)			(124)			(100)		(100)		(450)				(450)
Distributions to noncontrolling interest in subsidiaries	(65)										(65)						(37)							(37)
Transfer of service company net assets to Duke Energy																	(539)		(539)				(539)
Other	(3)										(3)						(4)							(4)
Balance (in shares) at Dec. 31, 2014		707,000,000
Balance at Dec. 31, 2014	40,899	$ 1	39,405	2,012	(439)		(59)	3	(48)	40,875	24						11,176	7,467	3,782	(35)	1	(7)	11,208	(32)	5,867	2,159		3,708	5,222	1,762		3,460			4,674	762	4,782	(870)	3,848	1	1,384		2,460	3
Ending member's equity at Dec. 31, 2014													10,924	10,937	(12)	(1)
Net Income (Loss)	2,831			2,816						2,816	15						1,062		1,051				1,051	11
Net Income (Loss) Attributable to Parent	2,816												1,081	1,081			1,051								566		$ 211	355	599		$ 248	351			172			172	316				316
Other comprehensive income (loss), net of tax	(274)				(253)		9	(6)	(13)	(263)	(11)		2		1	1	(7)			4	(1)	(10)	(7)						0										(2)					(2)
Distribution to Parent													(401)	(401)															(350)		(350)
Common stock issuances, including dividend reinvestment and employee benefits (in shares)		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	$ 63		63							63
Stock repurchase, shares	19,800,000	(20,000,000)
Stock repurchase	$ (1,500)		(1,500)							(1,500)
Common stock dividends	(2,254)			(2,254)						(2,254)																			(350)			(350)			(150)		(150)		$ (326)				(326)
Distributions to noncontrolling interest in subsidiaries	(9)										(9)						(4)							(4)
Capital contribution from parent																	625	625					625		626		626
Distribution of membership interest of Duke Energy SAM, LLC to parent																																			$ (1,912)		(1,912)
Other	$ 15			(10)						(10)	25	[1]					$ 1		(2)				(2)	3		$ (2,159)	6,222	$ (4,063)		$ (1,762)	5,223	$ (3,461)
Balance (in shares) at Dec. 31, 2015	688,000,000	688,000,000															100,000,000																		89,663,086				53,913,701
Balance at Dec. 31, 2015	$ 39,771	$ 1	37,968	2,564	(692)		(50)	(3)	(61)	39,727	44						$ 12,853	8,092	4,831	(31)	0	(17)	12,875	(22)											$ 2,784	762	2,720	(698)	$ 3,836	1	1,384		2,450	1
Ending member's equity at Dec. 31, 2015													11,606	11,617	(11)	0									7,059		7,059		5,121		5,121
Net Income (Loss)	2,170			2,152						2,152	18						1,041		1,031				1,031	10
Net Income (Loss) Attributable to Parent	2,152												1,166	1,166			1,031								599		599		551		551				228			228	381			$ 381
Other comprehensive income (loss), net of tax	715				$ 692	[2]	30	2	(11)	713	2		2		2	$ 0	10			8	1	1	10						1					$ 1					(1)			0		$ (1)
Distribution to Parent													(2,000)	(2,000)											(300)		(300)		(775)		(775)								$ (149)			(149)
Common stock issuances, including dividend reinvestment and employee benefits (in shares)		12,000,000
Common stock issuances, including dividend reinvestment and employee benefits	773		773							773
Common stock dividends	(2,332)			(2,332)						(2,332)							(2,098)		(2,098)				(2,098)												(25)		(25)
Distributions to noncontrolling interest in subsidiaries	(6)										(6)						(1)							(1)
Capital contribution from parent																																			$ 9			9
Other	$ (50)										(50)	[3]	(2)	(2)			$ 2	2	0				2	0					2		2									$ (1)	$ (1,384)	3,835	$ (2,450)
Balance (in shares) at Dec. 31, 2016	700,000,000	700,000,000															100,000,000																		89,663,086				53,913,701
Balance at Dec. 31, 2016	$ 41,041	$ 1	$ 38,741	$ 2,384			$ (20)	$ (1)	$ (72)	$ 41,033	$ 8						$ 11,807	$ 8,094	$ 3,764	$ (23)	$ 1	$ (16)	$ 11,820	$ (13)										$ 1	$ 2,996	$ 762	$ 2,695	$ (461)
Ending member's equity at Dec. 31, 2016													$ 10,772	$ 10,781	$ (9)										$ 7,358		$ 7,358		$ 4,900		$ 4,899								$ 4,067			$ 4,067
[1]	Noncontrolling Interests amount is primarily related to the acquisitions of a majority interest in a provider of energy management systems and services for commercial customers and a solar company.
[2]	Foreign Currency Translation Adjustments amount includes $620 million of cumulative adjustment realized as a result of the sale of the Latin American generation business. Refer to Note 2 to the Consolidated Financial Statements.
[3]	Noncontrolling Interests amount is primarily related to the sale of the Latin American generation business. Refer to Note 2 to the Consolidated Financial Statements.

Consolidated Statements of Equ9

Consolidated Statements of Equity (Parenthetical) (Parentheticals) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
International Energy [Member]
Disposal Group, Including Discontinued Operation, Foreign Currency Translation Gains (Losses)	$ 620

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Index to Combined Notes To Consolidated Financial Statements The notes to the consolidated financial statements are a combined presentation. The following table indicates the registrants to which the notes apply. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Duke Energy Corporation • • • • • • • • • • • • • • • • • • • • • • • • Duke Energy Carolinas, LLC • • • • • • • • • • • • • • • • • • • • • Progress Energy, Inc. • • • • • • • • • • • • • • • • • • • • • • • Duke Energy Progress, LLC • • • • • • • • • • • • • • • • • • • • • Duke Energy Florida, LLC • • • • • • • • • • • • • • • • • • • • • • Duke Energy Ohio, Inc. • • • • • • • • • • • • • • • • • • • • • Duke Energy Indiana, LLC • • • • • • • • • • • • • • • • • • • • • Tables within the notes may not sum across due to (i) Progress Energy's consolidation of Duke Energy Progress, Duke Energy Florida and other subsidiaries that are not registrants, (ii) Piedmont, a subsidiary registrant acquired on October 3, 2016, which is consolidated within Duke Energy but not separately stated in the combined presentation and (iii) other subsidiaries that are not registrants but included in the consolidated Duke Energy balances. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations and Basis of Consolidation Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) primarily through its direct and indirect subsidiaries. Certain Duke Energy subsidiaries are also subsidiary registrants, including Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, LLC (Duke Energy Progress); Duke Energy Florida, LLC (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio); and Duke Energy Indiana, LLC (Duke Energy Indiana). On October 3, 2016, Duke Energy acquired Piedmont Natural Gas Company, Inc. (Piedmont) which also became a wholly owned subsidiary and subsidiary registrant of Duke Energy. Duke Energy's consolidated financial statements include Piedmont's results of operations and cash flow activity subsequent to the acquisition. See Note 2 for additional information regarding the acquisition. When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its seven separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants). In October 2016, Duke Energy completed the acquisition of Piedmont, an energy services company whose principal business is the distribution of natural gas, for a total cash purchase price of $5.0 billion . The acquisition provides a foundation for establishing a broader strategic natural gas infrastructure platform within Duke Energy to complement the existing natural gas pipeline investments and the natural gas business located in the Midwest. For additional information on the details of this transaction including purchase price allocation and acquisition financing, see Note 2 . Piedmont continues to maintain reporting requirements as a Securities and Exchange Commission (SEC) registrant. In December 2016, Duke Energy completed an exit of the Latin American market to focus on its domestic regulated business, which was further bolstered by the acquisition of Piedmont. The sale of the International Energy business segment, excluding an equity method investment in National Methanol Company (NMC), was completed through two transactions including a sale of assets in Brazil to China Three Gorges (Luxembourg) Energy S.à.r.l. (CTG) and a sale of Duke Energy's remaining Latin American assets in Peru, Chile, Ecuador, Guatemala, El Salvador and Argentina to ISQ Enerlam Aggregator, L.P. and Enerlam (UK) Holding Ltd. (I Squared) (collectively, the International Disposal Group). For additional information on the sale of International Energy see Note 2 . The information in these combined notes relates to each of the Duke Energy Registrants, excluding Piedmont, as noted in the Index to Combined Notes to Consolidated Financial Statements. However, none of the registrants make any representation as to information related solely to Duke Energy or the Subsidiary Registrants of Duke Energy other than itself. These Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), Public Service Commission of South Carolina (PSCSC), U.S. Nuclear Regulatory Commission (NRC) and FERC. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting. Progress Energy is a public utility holding company headquartered in Raleigh, North Carolina, subject to regulation by the FERC. Progress Energy conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Substantially all of Progress Energy’s operations qualify for regulatory accounting. Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the Florida Public Service Commission (FPSC), NRC and FERC. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio also conducts competitive auctions for retail electricity supply in Ohio whereby recovery of the energy price is from retail customers and recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). For further information about the sale of the Midwest Generation business, refer to Note 2 "Acquisitions and Dispositions." Substantially all of Duke Energy Ohio's operations that remain after the sale qualify for regulatory accounting. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and FERC. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company. Piedmont is a regulated public utility primarily engaged in the distribution of natural gas in portions of North Carolina, South Carolina and Tennessee. Piedmont is invested in joint venture businesses including regulated interstate natural gas transportation and storage and intrastate natural gas transportation businesses. Piedmont is subject to the regulatory provisions of the NCUC, PSCSC, Tennessee Regulatory Authority (TRA) and FERC. Substantially all of Piedmont's operations qualify for regulatory accounting. Certain prior year amounts have been reclassified to conform to the current year presentation. Other Current Assets and Liabilities The following table provides a description of amounts included in Other within Current Assets or Current Liabilities that exceed 5 percent of total Current Assets or Current Liabilities on the Duke Energy Registrants' Consolidated Balance Sheets at either December 31, 2016 or 2015 . December 31, (in millions) Location 2016 2015 Duke Energy Accrued compensation Current Liabilities $ 765 $ 619 Duke Energy Carolinas Accrued compensation Current Liabilities $ 248 $ 213 Collateral liabilities Current Liabilities 155 141 Progress Energy Income taxes receivable Current Assets $ 19 $ 129 Customer deposits Current Liabilities 363 373 Derivative liabilities Current Liabilities 1 201 Duke Energy Progress Income taxes receivable Current Assets $ 16 $ 111 Customer deposits Current Liabilities 141 141 Accrued compensation Current Liabilities 135 108 Derivative liabilities Current Liabilities — 76 Duke Energy Florida Customer deposits Current Liabilities $ 222 $ 232 Derivative liabilities Current Liabilities 1 125 Duke Energy Ohio Income taxes receivable Current Assets $ 16 $ 59 Other receivable Current Assets — 33 Accrued litigation reserve Current Liabilities 4 80 Collateral liabilities Current Liabilities 62 48 Duke Energy Indiana Collateral liabilities Current Liabilities $ 44 $ 44 Discontinued Operations The results of operations of the International Disposal Group and Duke Energy Ohio's nonregulated Midwest Generation business and Duke Energy Retail Sales, LLC (collectively, Midwest Generation Disposal Group) have been classified as Discontinued Operations on Duke Energy's Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these consolidated financial statements exclude amounts related to discontinued operations for all periods presented and assets held for sale (AHFS) and liabilities associated with AHFS as of December 31, 2015. See Note 2 for additional information. Amounts Attributable to Controlling Interests Duke Energy's amount of (Loss) Income from Discontinued Operations, net of tax presented on the Consolidated Statements of Operations includes amounts attributable to noncontrolling interest. The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations. Year ended December 31, (in millions) 2016 2015 2014 Income from Continuing Operations $ 2,578 $ 2,654 $ 2,538 Income from Continuing Operations Attributable to Noncontrolling Interests 7 9 5 Income from Continuing Operations Attributable to Duke Energy Corporation $ 2,571 $ 2,645 $ 2,533 (Loss) Income From Discontinued Operations, net of tax $ (408 ) $ 177 $ (649 ) Income from Discontinued Operations Attributable to Noncontrolling Interests, net of tax 11 6 1 (Loss) Income From Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ (419 ) $ 171 $ (650 ) Net Income $ 2,170 $ 2,831 $ 1,889 Net Income Attributable to Noncontrolling Interests 18 15 6 Net Income Attributable to Duke Energy Corporation $ 2,152 $ 2,816 $ 1,883 Significant Accounting Policies Use of Estimates In preparing financial statements that conform to generally accepted accounting principles (GAAP) in the U.S., the Duke Energy Registrants must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. Regulatory Accounting The majority of the Duke Energy Registrants’ operations are subject to price regulation for the sale of electricity and natural gas by state utility commissions or FERC. When prices are set on the basis of specific costs of the regulated operations and an effective franchise is in place such that sufficient natural gas or electric services can be sold to recover those costs, the Duke Energy Registrants apply regulatory accounting. Regulatory accounting changes the timing of the recognition of costs or revenues relative to a company that does not apply regulatory accounting. As a result, Regulatory assets and Regulatory liabilities are recognized on the Consolidated Balance Sheets. Regulatory assets and liabilities are amortized consistent with the treatment of the related cost in the ratemaking process. See Note 4 for further information. Regulatory accounting rules also require recognition of a disallowance (also called "impairment") loss if it becomes probable that part of the cost of a plant under construction (or a recently completed plant or an abandoned plant) will be disallowed for ratemaking purposes and a reasonable estimate of the amount of the disallowance can be made. Other disallowances can require judgments on allowed future rate recovery. When it becomes probable that regulated generation, transmission or distribution assets will be abandoned, the cost of the asset is removed from plant in service. The value that may be retained as a regulatory asset on the balance sheet for the abandoned property is dependent upon amounts that may be recovered through regulated rates, including any return. As such, an impairment charge could be partially or fully offset by the establishment of a regulatory asset if rate recovery is probable. The impairment for a disallowance of costs for regulated plants under construction, recently completed or abandoned is based on discounted cash flows. Regulated Fuel and Purchased Gas Adjustment Clauses The Duke Energy Registrants utilize cost-tracking mechanisms, commonly referred to as fuel adjustment clauses or purchased gas adjustment clauses (PGA). These clauses allow for the recovery of fuel and fuel-related costs, portions of purchased power, natural gas costs and hedging costs through surcharges on customer rates. The difference between the costs incurred and the surcharge revenues is recorded either as an adjustment to Operating Revenues, Operating Expenses – Fuel used in electric generation or Operating Expenses – Cost of natural gas on the Consolidated Statements of Operations, with an off-setting impact on regulatory assets or liabilities. Cash and Cash Equivalents All highly liquid investments with maturities of three months or less at the date of acquisition are considered cash equivalents. Restricted Cash The Duke Energy Registrants have restricted cash related primarily to collateral assets, escrow deposits and variable interest entities (VIEs). Restricted cash balances are reflected in Other within Current Assets and in Other within Investments and Other Assets on the Consolidated Balance Sheets. At December 31, 2016 and 2015 , Duke Energy had restricted cash totaling $137 million and $98 million , respectively. Inventory Inventory is used for operations and is recorded primarily using the average cost method. Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Materials and supplies are recorded as inventory when purchased and subsequently charged to expense or capitalized to property, plant and equipment when installed. Reserves are established for excess and obsolete inventory. Inventory reserves were not material at December 31, 2016 and 2015 . The components of inventory are presented in the tables below. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,374 $ 767 $ 1,167 $ 813 $ 354 $ 84 $ 312 Coal 774 251 314 148 166 19 190 Natural gas, oil and other 374 37 236 115 121 34 2 Total inventory $ 3,522 $ 1,055 $ 1,717 $ 1,076 $ 641 $ 137 $ 504 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,343 $ 785 $ 1,133 $ 776 $ 357 $ 81 $ 301 Coal 1,105 451 370 192 178 16 267 Natural gas, oil and other 298 40 248 120 128 8 2 Total inventory $ 3,746 $ 1,276 $ 1,751 $ 1,088 $ 663 $ 105 $ 570 Investments in Debt and Equity Securities The Duke Energy Registrants classify investments into two categories – trading and available-for-sale. Both categories are recorded at fair value on the Consolidated Balance Sheets. Realized and unrealized gains and losses on trading securities are included in earnings. For certain investments of regulated operations, such as the Nuclear Decommissioning Trust Fund (NDTF), realized and unrealized gains and losses (including any other-than-temporary impairments (OTTIs)) on available-for-sale securities are recorded as a regulatory asset or liability. Otherwise, unrealized gains and losses are included in Accumulated Other Comprehensive Income (AOCI), unless other-than-temporarily impaired. OTTIs for equity securities and the credit loss portion of debt securities of nonregulated operations are included in earnings. Investments in debt and equity securities are classified as either current or noncurrent based on management’s intent and ability to sell these securities, taking into consideration current market liquidity. See Note 15 for further information. Goodwill and Intangible Assets Goodwill Duke Energy, Progress Energy and Duke Energy Ohio perform annual goodwill impairment tests as of August 31 each year at the reporting unit level, which is determined to be an operating segment or one level below. Duke Energy, Progress Energy and Duke Energy Ohio update these tests between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. Intangible Assets Intangible assets are included in Other in Investments and Other Assets on the Consolidated Balance Sheets. Generally, intangible assets are amortized using an amortization method that reflects the pattern in which the economic benefits of the intangible asset are consumed or on a straight-line basis if that pattern is not readily determinable. Amortization of intangibles is reflected in Depreciation and amortization on the Consolidated Statements of Operations. Intangible assets are subject to impairment testing and if impaired, the carrying value is accordingly reduced. Emission allowances permit the holder of the allowance to emit certain gaseous byproducts of fossil fuel combustion, including sulfur dioxide (SO 2 ) and nitrogen oxide. Allowances are issued by the U.S. Environmental Protection Agency (EPA) at zero cost and may also be bought and sold via third-party transactions. Allowances allocated to or acquired by the Duke Energy Registrants are held primarily for consumption. Carrying amounts for emission allowances are based on the cost to acquire the allowances or, in the case of a business combination, on the fair value assigned in the allocation of the purchase price of the acquired business. Emission allowances are expensed to Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Renewable energy certificates are used to measure compliance with renewable energy standards and are held primarily for consumption. See Note 11 for further information. Long-Lived Asset Impairments The Duke Energy Registrants evaluate long-lived assets, excluding goodwill, for impairment when circumstances indicate the carrying value of those assets may not be recoverable. An impairment exists when a long-lived asset’s carrying value exceeds the estimated undiscounted cash flows expected to result from the use and eventual disposition of the asset. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, the carrying value of the asset is written-down to its then-current estimated fair value and an impairment charge is recognized. The Duke Energy Registrants assess fair value of long-lived assets using various methods, including recent comparable third-party sales, internally developed discounted cash flow analysis and analysis from outside advisors. Significant changes in commodity prices, the condition of an asset or management’s interest in selling the asset are generally viewed as triggering events to reassess cash flows. Property, Plant and Equipment Property, plant and equipment are stated at the lower of depreciated historical cost net of any disallowances or fair value, if impaired. The Duke Energy Registrants capitalize all construction-related direct labor and material costs, as well as indirect construction costs such as general engineering, taxes and financing costs. See “Allowance for Funds Used During Construction (AFUDC) and Interest Capitalized” for information on capitalized financing costs. Costs of renewals and betterments that extend the useful life of property, plant and equipment are also capitalized. The cost of repairs, replacements and major maintenance projects, which do not extend the useful life or increase the expected output of the asset, are expensed as incurred. Depreciation is generally computed over the estimated useful life of the asset using the composite straight-line method. Depreciation studies are conducted periodically to update composite rates and are approved by state utility commissions and/or the FERC when required. The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2016 2015 2014 Duke Energy 2.8 % 2.9 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.7 % Progress Energy 2.7 % 2.6 % 2.5 % Duke Energy Progress 2.6 % 2.6 % 2.5 % Duke Energy Florida 2.8 % 2.7 % 2.7 % Duke Energy Ohio 2.6 % 2.7 % 2.3 % Duke Energy Indiana 3.1 % 3.0 % 3.0 % In general, when the Duke Energy Registrants retire regulated property, plant and equipment, the original cost plus the cost of retirement, less salvage value, is charged to accumulated depreciation. However, when it becomes probable the asset will be retired substantially in advance of its original expected useful life or is abandoned, the cost of the asset and the corresponding accumulated depreciation is recognized as a separate asset. If the asset is still in operation, the net amount is classified as Generation facilities to be retired, net on the Consolidated Balance Sheets. If the asset is no longer operating, the net amount is classified in Regulatory Assets on the Consolidated Balance Sheets. When it becomes probable that meters or other regulated mass utility assets will be abandoned, the cost of the asset and accumulated depreciation is reclassified to regulatory assets for amounts recoverable in rates. The carrying value of the asset is based on historical cost if the Duke Energy Registrants are allowed to recover the remaining net book value and a return equal to at least the incremental borrowing rate. If not, an impairment is recognized to the extent the net book value of the asset exceeds the present value of future revenues discounted at the incremental borrowing rate. When the Duke Energy Registrants sell entire regulated operating units, or retire or sell nonregulated properties, the original cost and accumulated depreciation and amortization balances are removed from Property, Plant and Equipment on the Consolidated Balance Sheets. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body. See Note 10 for further information. Nuclear Fuel Nuclear fuel is classified as Property, Plant and Equipment on the Consolidated Balance Sheets, except for Duke Energy Florida. Nuclear fuel amounts at Duke Energy Florida were reclassified to Regulatory assets pursuant to a settlement among Duke Energy Florida, the Florida Office of Public Counsel (Florida OPC) and other customer advocates (the 2013 Settlement). Portions of the nuclear fuel balances that were under contract for sale were subsequently moved to Other within Current Assets and Other within Investments and Other Assets on the Consolidated Balance Sheets. Nuclear fuel in the front-end fuel processing phase is considered work in progress and not amortized until placed in service. Amortization of nuclear fuel is included within Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Amortization is recorded using the units-of-production method. Allowance for Funds Used During Construction and Interest Capitalized For regulated operations, the debt and equity costs of financing the construction of property, plant and equipment are reflected as AFUDC and capitalized as a component of the cost of property, plant and equipment. AFUDC equity is reported on the Consolidated Statements of Operations as non-cash income in Other income and expenses, net. AFUDC debt is reported as a non-cash offset to Interest Expense. After construction is completed, the Duke Energy Registrants are permitted to recover these costs through their inclusion in rate base and the corresponding subsequent depreciation or amortization of those regulated assets. AFUDC equity, a permanent difference for income taxes, reduces the effective tax rate (ETR) when capitalized and increases the ETR when depreciated or amortized. See Note 22 for additional information. For nonregulated operations, interest is capitalized during the construction phase with an offsetting non-cash credit to Interest Expense on the Consolidated Statements of Operations. Asset Retirement Obligations Asset retirement obligations (AROs) are recognized for legal obligations associated with the retirement of property, plant and equipment. Substantially all AROs are related to regulated operations. When recording an ARO, the present value of the projected liability is recognized in the period in which it is incurred, if a reasonable estimate of fair value can be made. The liability is accreted over time. For operating plants, the present value of the liability is added to the cost of the associated asset and depreciated over the remaining life of the asset. For retired plants, the present value of the liability is recorded as a regulatory asset unless determined not to be recoverable. The present value of the initial obligation and subsequent updates are based on discounted cash flows, which include estimates regarding timing of future cash flows, selection of discount rates and cost escalation rates, among other factors. These estimates are subject to change. Depreciation expense is adjusted prospectively for any changes to the carrying amount of the associated asset. The Duke Energy Registrants receive amounts to fund the cost of the ARO for regulated operations through a combination of regulated revenues and earnings on the NDTF. As a result, amounts recovered in regulated revenues, earnings on the NDTF, accretion expense and depreciation of the associated asset are netted and deferred as a regulatory asset or liability. Obligations for nuclear decommissioning are based on site-specific cost studies. Duke Energy Carolinas and Duke Energy Progress assume prompt dismantlement of the nuclear facilities after operations are ceased. Duke Energy Florida assumes Crystal River Unit 3 Nuclear Plant (Crystal River Unit 3) will be placed into a safe storage configuration until eventual dismantlement is completed by 2074. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida also assume that spent fuel will be stored on-site until such time that it can be transferred to a yet to be built U.S. Department of Energy (DOE) facility. Obligations for closure of ash basins are based upon discounted cash flows of estimated costs for site-specific plans, if known, or probability weightings of the potential closure methods if the closure plans are under development and multiple closure options are being considered and evaluated on a site-by-site basis. See Note 9 for additional information. Revenue Recognition and Unbilled Revenue Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy or natural gas delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills and meter reading schedules. Unbilled revenues are included within Receivables and Restricted receivables of VIEs on the Consolidated Balance Sheets as shown in the following table. December 31, (in millions) 2016 2015 Duke Energy $ 831 $ 677 Duke Energy Carolinas 313 283 Progress Energy 161 172 Duke Energy Progress 102 102 Duke Energy Florida 59 70 Duke Energy Ohio 2 3 Duke Energy Indiana 32 31 Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company LLC (CRC) and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 17 for further information. These receivables for unbilled revenues are shown in the table below. December 31, (in millions) 2016 2015 Duke Energy Ohio $ 97 $ 71 Duke Energy Indiana 123 97 Allowance for Doubtful Accounts Allowances for doubtful accounts are presented in the following table. December 31, (in millions) 2016 2015 2014 Allowance for Doubtful Accounts Duke Energy $ 14 $ 12 $ 14 Duke Energy Carolinas 2 3 3 Progress Energy 6 6 8 Duke Energy Progress 4 4 7 Duke Energy Florida 2 2 2 Duke Energy Ohio 2 2 2 Duke Energy Indiana 1 1 1 Allowance for Doubtful Accounts – VIEs Duke Energy $ 54 $ 53 $ 51 Duke Energy Carolinas 7 7 6 Progress Energy 7 8 8 Duke Energy Progress 5 5 5 Duke Energy Florida 2 3 3 Derivatives and Hedging Derivative and non-derivative instruments may be used in connection with commodity price and interest rate activities, including swaps, futures, forwards and options. All derivative instruments, except those that qualify for the normal purchase/normal sale (NPNS) exception, are recorded on the Consolidated Balance Sheets at fair value. Qualifying derivative instruments may be designated as either cash flow hedges or fair value hedges. Other derivative instruments (undesignated contracts) either have not been designated or do not qualify as hedges. The effective portion of the change in the fair value of cash flow hedges is recorded in AOCI. The effective portion of the change in the fair value of a fair value hedge is offset in net income by changes in the hedged item. For activity subject to regulatory accounting, gains and losses on derivative contracts are reflected as regulatory assets or liabilities and not as other comprehensive income or current period income. As a result, changes in fair value of these derivatives have no immediate earnings impact. Formal documentation, including transaction type and risk management strategy, is maintained for all contracts accounted for as a hedge. At inception and at least every three months thereafter, the hedge contract is assessed to see if it is highly effective in offsetting changes in cash flows or fair values of hedged items. See Note 14 for further information. Captive Insurance Reserves Duke Ene

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS ACQUISITIONS The Duke Energy Registrants consolidate assets and liabilities from acquisitions as of the purchase date and include earnings from acquisitions in consolidated earnings after the purchase date. Acquisition of Piedmont Natural Gas On October 3, 2016, Duke Energy acquired all outstanding common stock of Piedmont for a total cash purchase price of $5.0 billion and assumed Piedmont's existing long-term debt, which had an estimated fair value of approximately $2.0 billion at the time of the acquisition. Piedmont is a North Carolina corporation primarily engaged in regulated natural gas distribution to residential, commercial, industrial and power generation customers in portions of North Carolina, South Carolina and Tennessee. Piedmont is also invested in joint-venture, energy-related businesses, including regulated interstate natural gas transportation and storage and regulated intrastate natural gas transportation. The acquisition provides a foundation for Duke Energy to establish a broader, long-term strategic natural gas infrastructure platform to complement its existing natural gas pipeline investments and regulated natural gas business in the Midwest. In connection with the closing of the acquisition, Piedmont became a wholly owned subsidiary of Duke Energy. Preliminary Purchase Price Allocation The preliminary purchase price allocation of the Piedmont acquisition is estimated as follows: (in millions) Current assets $ 497 Property, plant and equipment, net 4,714 Goodwill 3,353 Other long-term assets 804 Total assets 9,368 Current liabilities, including current maturities of long-term debt 576 Long-term liabilities 1,790 Long-term debt 2,002 Total liabilities 4,368 Total purchase price $ 5,000 The fair value of Piedmont's assets and liabilities were determined based on significant estimates and assumptions that are judgmental in nature, including projected future cash flows (including timing); discount rates reflecting risk inherent in the future cash flows and market prices of long-term debt. The preliminary amounts are subject to revision to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. The majority of Piedmont’s operations are subject to the rate-setting authority of the NCUC, the PSCSC and the TRA and are accounted for pursuant to accounting guidance for regulated operations. The rate-setting and cost recovery provisions currently in place for Piedmont’s regulated operations provide revenues derived from costs, including a return on investment of assets and liabilities included in rate base. Thus, the fair value of Piedmont's assets and liabilities subject to these rate-setting provisions approximates the pre-acquisition carrying values and does not reflect any net valuation adjustments. The significant assets and liabilities for which valuation adjustments were reflected within the purchase price allocation include the acquired equity method investments and long-term debt. The difference between the preliminary fair value and the pre-merger carrying values of long-term debt for regulated operations was recorded as a regulatory asset. The excess of the purchase price over the estimated fair value of Piedmont's assets and liabilities on the acquisition date was recorded as goodwill. The goodwill reflects the value paid by Duke Energy primarily for establishing a broader, long-term strategic natural gas infrastructure platform, an improved risk profile and expected synergies resulting from the combined entities. See Note 11 for information related to the allocation of goodwill to Duke Energy’s reporting units. Accounting Charges Related to the Acquisition Duke Energy incurred pretax non-recurring transaction and integration costs associated with the acquisition of $439 million and $9 million for the years ended December 31, 2016 and 2015, respectively. Amounts recorded on the Consolidated Statements of Operations in 2016 include: • Interest expense of $234 million related to the acquisition financing, including realized losses on forward-starting interest rate swaps of $190 million . See Note 14 for additional information on the swaps. • Charges of $104 million related to commitments made in conjunction with the transaction, including charitable contributions and a one-time bill credit to Piedmont customers. $10 million was recorded as a reduction in Operating Revenues, with the remaining $94 million recorded within Operation, maintenance and other. • Other transaction and integration costs of $101 million recorded to Operation, maintenance and other, including professional fees and severance. Pro Forma Financial Information The following unaudited pro forma financial information reflects the combined results of operations of Duke Energy and Piedmont as if the merger had occurred as of January 1, 2015. The pro forma financial information does not include potential cost savings, intercompany revenues, Piedmont’s earnings from a certain equity method investment sold immediately prior to the merger or non-recurring transaction and integration costs incurred by Duke Energy and Piedmont. The after-tax non-recurring transaction and integration costs incurred by Duke Energy and Piedmont were $279 million and $19 million for the years ended December 31, 2016 and 2015, respectively. This information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Duke Energy. Years Ended December 31, (in millions) 2016 2015 Operating Revenues $ 23,504 $ 23,570 Net Income Attributable to Duke Energy Corporation 2,442 2,877 Piedmont's Earnings Piedmont's revenues and net income included in Duke Energy's Consolidated Statements of Operations for the year ended December 31, 2016, were $367 million and $20 million , respectively. Piedmont's revenues and net income for the year ended December 31, 2016 include the impact of non-recurring transaction costs of $10 million and $46 million , respectively. Acquisition Related Financings and Other Matters Duke Energy financed the Piedmont acquisition with a combination of debt and equity issuances and other cash sources, including: • $3.75 billion of long-term debt issued in August 2016. • $750 million borrowed under the $1.5 billion short-term loan facility in September 2016, which was repaid in December 2016. • 10.6 million shares of common stock issued in October 2016 for net cash proceeds of approximately $723 million . The $4.9 billion senior unsecured bridge financing facility (Bridge Facility) with Barclays Capital, Inc. (Barclays) was terminated following the issuance of the long-term debt. For additional information related to the debt and equity issuances, see Notes 6 and 18, respectively. For additional information regarding Duke Energy's and Piedmont's joint investment in Atlantic Coast Pipeline, LLC (ACP), see Note 4. Purchase of NCEMPA's Generation On July 31, 2015, Duke Energy Progress completed the purchase of North Carolina Eastern Municipal Power Agency’s (NCEMPA) ownership interests in certain generating assets, fuel and spare parts inventory jointly owned with and operated by Duke Energy Progress for approximately $1.25 billion . This purchase was accounted for as an asset acquisition. The purchase resulted in the acquisition of a total of approximately 700 megawatts (MW) of generating capacity at Brunswick Nuclear Plant (Brunswick), Shearon Harris Nuclear Plant (Harris), Mayo Steam Plant and Roxboro Steam Plant. In connection with this transaction, Duke Energy Progress and NCEMPA entered into a 30-year wholesale power agreement, whereby Duke Energy Progress will sell power to NCEMPA to continue to meet the needs of NCEMPA customers. The purchase price exceeded the historical carrying value of the acquired assets by $350 million , which was recognized as an acquisition adjustment and recorded in property, plant and equipment. Duke Energy Progress established a rider in North Carolina to recover the costs to acquire, operate and maintain interests in the assets purchased as allocated to its North Carolina retail operations, including the purchase acquisition adjustment, and included the purchase acquisition adjustment in wholesale power formula rates. Duke Energy Progress received an order from the PSCSC to defer recovery of the South Carolina retail allocated costs of the asset purchased until Duke Energy Progress' next general rate case, which was filed in July 2016. In October 2016, Duke Energy Progress, the Office of Regulatory Staff (ORS) and intervenors entered into a settlement agreement that provides for recovery of the historical carrying value of the South Carolina allocated purchased costs of the transaction. The settlement agreement was approved by the PSCSC in December 2016. See Note 4 for additional information on the South Carolina rate case. The ownership interests in generating assets acquired are subject to rate-setting authority of the FERC, NCUC and PSCSC and accordingly, the assets are recorded at historical cost. The assets acquired are presented in the following table. (in millions) Inventory $ 56 Net property, plant and equipment 845 Total assets 901 Acquisition adjustment, recorded within property, plant and equipment 350 Total purchase price $ 1,251 In connection with the acquisition, Duke Energy Progress acquired NCEMPA's NDTF assets of $287 million and assumed AROs of $204 million associated with NCEMPA's interest in the generation assets. The NDTF and the AROs are subject to regulatory accounting treatment. DISPOSITIONS The following table summarizes the (Loss) Income from Discontinued Operations, net of tax recorded on Duke Energy's Consolidated Statements of Operations: Years Ended December 31, (in millions) 2016 2015 2014 International Energy Disposal Group $ (534 ) $ 157 $ (73 ) Midwest Generation Disposal Group 36 33 (524 ) Other (a) 90 (13 ) (52 ) (Loss) Income from Discontinued Operations, net of tax $ (408 ) $ 177 $ (649 ) (a) Relates to previously sold businesses not related to the Disposal Groups. The amount for 2016 represents an income tax benefit resulting from immaterial out of period deferred tax liability adjustments. The amounts for 2015 and 2014 include indemnifications provided for certain legal, tax and environmental matters and foreign currency translation adjustments. Sale of International Energy In February 2016, Duke Energy announced it had initiated a process to divest its International Energy businesses, excluding the equity method investment in NMC (the International Disposal Group), and in October 2016, announced it had entered into two separate purchase and sale agreements to execute the divestiture. Both sales closed in December of 2016, resulting in available cash proceeds of $1.9 billion , excluding transaction costs. Proceeds were primarily used to reduce Duke Energy holding company debt. Existing favorable tax attributes result in no immediate U.S. federal-level cash tax impacts. Details of each transaction are as follows: • On December 20, 2016, Duke Energy closed on the sale of its ownership interests in businesses in Argentina, Chile, Ecuador, El Salvador, Guatemala and Peru to I Squared Capital. The assets sold included approximately 2,230 MW of hydroelectric and natural gas generation capacity, transmission infrastructure and natural gas processing facilities. I Squared Capital purchased the businesses for an enterprise value of $1.2 billion . • On December 29, 2016, Duke Energy closed on the sale of its Brazilian business, which included approximately 2,090 MW of hydroelectric generation capacity, to CTG for an enterprise value of $1.2 billion . With the closing of the CTG deal, Duke Energy finalized its exit from the Latin American market. Assets Held For Sale and Discontinued Operations As a result of the transactions, the International Disposal Group was classified as held for sale and as discontinued operations in the fourth quarter of 2016. Interest expense directly associated with the International Disposal Group was allocated to discontinued operations. No interest from corporate level debt was allocated to discontinued operations. The following table presents the carrying values of the major classes of Assets held for sale and Liabilities associated with assets held for sale included in the Consolidated Balance Sheets. As a result of Duke Energy closing both transactions in December 2016, there are no Assets held for sale or Liabilities associated with assets held for sale as of December 31, 2016. (in millions) December 31, 2015 Current assets held for sale Cash and cash equivalents $ 474 Receivables, net 188 Inventory 65 Other 19 Total current assets held for sale 746 Noncurrent assets held for sale Property, Plant and Equipment Cost 2,859 Accumulated depreciation and amortization (930 ) Net property, plant and equipment 1,929 Goodwill 271 Other 213 Total noncurrent assets held for sale 2,413 Total assets held for sale $ 3,159 Current liabilities associated with assets held for sale Accounts payable $ 51 Taxes accrued 60 Current maturities of long-term debt 48 Other 120 Total current liabilities associated with assets held for sale 279 Noncurrent liabilities associated with assets held for sale Long-Term Debt 653 Deferred income taxes 157 Other 90 Total noncurrent liabilities associated with assets held for sale 900 Total liabilities associated with assets held for sale $ 1,179 The value of goodwill increased by $7 million from December 31, 2015 through the date of sale as a result of changes in foreign currency exchanges rates. At the time of the disposition, the International Disposal Group included goodwill of $278 million . The following table presents the results of the International Disposal Group which are included in (Loss) Income from Discontinued Operations, net of tax in Duke Energy's Consolidated Statements of Operations. Years Ended December 31, (in millions) 2016 2015 2014 Operating Revenues $ 988 $ 1,088 $ 1,417 Fuel used in electric generation and purchased power 227 306 486 Cost of natural gas 43 53 63 Operation, maintenance and other 341 334 352 Depreciation and amortization (a) 62 92 97 Property and other taxes 15 7 9 Impairment charges (b) 194 13 — (Loss) Gains on Sales of Other Assets and Other, net (3 ) 6 6 Other Income and Expenses, net 58 23 47 Interest Expense 82 85 93 Pretax loss on disposal (c) (514 ) — — (Loss) Income before income taxes (d) (435 ) 227 370 Income tax expense (e)(f) 99 70 443 (Loss) Income from discontinued operations of the International Disposal Group $ (534 ) $ 157 $ (73 ) (a) Upon meeting the criteria for assets held for sale, beginning in the fourth quarter of 2016 depreciation expense was ceased. (b) In conjunction with the advancements of marketing efforts during 2016, Duke Energy performed recoverability tests of the long-lived asset groups of International Energy. As a result, Duke Energy determined the carrying value of certain assets in Central America was not fully recoverable and recorded a pretax impairment charge of $194 million . The charge represents the excess of carrying value over the estimated fair value of the assets, which was based on a Level 3 Fair Value measurement that was primarily determined from the income approach using discounted cash flows but also considered market information obtained in 2016. (c) The pretax loss on disposal includes the recognition of cumulative foreign currency translation losses of $620 million as of the disposal date. See the Consolidated Statements of Changes in Equity for additional information. (d) Pretax (Loss) Income attributable to Duke Energy Corporation was $(445) million , $221 million and $360 million for the years ended December 31, 2016, 2015 and 2014, respectively. (e) 2016 amount includes $126 million of income tax expense on the disposal, which primarily reflects in-country taxes incurred as a result of the sale. The after-tax loss on disposal was $640 million . (f) 2016 amount includes an income tax benefit of $95 million and 2014 amount includes an income tax charge of $373 million related to historical undistributed foreign earnings. See Note 22, "Income Taxes," for additional information. Duke Energy has elected not to separately disclose discontinued operations on the Consolidated Statements of Cash Flows. The following table summarizes Duke Energy's cash flows from discontinued operations related to the International Disposal Group. Years Ended December 31, (in millions) 2016 2015 2014 Cash flows provided by (used in): Operating activities $ 204 $ 248 $ 339 Investing activities (434 ) 177 111 Other Sale Related Matters Duke Energy will provide transition services to CTG and I Squared for a period not to extend beyond March 2017 and September 2017, respectively. In addition, Duke Energy will reimburse CTG and I Squared for all tax obligations arising from the period preceding consummation on the transactions, totaling approximately $78 million . Duke Energy has not recorded any other liabilities, contingent liabilities or indemnifications related to the International Disposal Group. Midwest Generation Exit Duke Energy, through indirect subsidiaries, completed the sale of the Midwest Generation Disposal Group to a subsidiary of Dynegy on April 2, 2015, for approximately $2.8 billion in cash. The nonregulated Midwest generation business included generation facilities with approximately 5,900 MW of owned capacity located in Ohio, Pennsylvania and Illinois. On April 1, 2015, prior to the sale, Duke Energy Ohio distributed its indirect ownership interest in the nonregulated Midwest generation business to a subsidiary of Duke Energy Corporation. Duke Energy utilized a revolving credit agreement (RCA) to support the operations of the nonregulated Midwest generation business. Duke Energy Ohio had a power purchase agreement with the Midwest Generation Disposal Group for a portion of its standard service offer (SSO) supply requirement. The agreement and the SSO expired in May 2015. The results of operations of the Midwest Generation Disposal Group prior to the date of sale are classified as discontinued operations in the accompanying Consolidated Statements of Operations. Interest expense associated with the RCA was allocated to discontinued operations. No other interest expense related to corporate level debt was allocated to discontinued operations. Certain immaterial costs that were eliminated as a result of the sale remained in continuing operations. The following table summarizes the Midwest Generation Disposal Group activity recorded within discontinued operations. Duke Energy Duke Energy Ohio Years Ended December 31, Years Ended December 31, (in millions) 2016 2015 2014 2016 2015 2014 Operating Revenues $ — $ 543 $ 1,748 $ — $ 412 $ 1,299 Pretax Loss on disposal (a) — (45 ) (929 ) — (52 ) (959 ) Income (loss) before income taxes (b) $ — $ 59 $ (818 ) $ — $ 44 $ (863 ) Income tax (benefit) expense (c) (36 ) 26 (294 ) (36 ) 21 (300 ) Income (loss) from discontinued operations $ 36 $ 33 $ (524 ) $ 36 $ 23 $ (563 ) (a) The Loss on disposal includes impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) 2015 amounts include the impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information about the lawsuit. (c) 2016 amounts result from immaterial out of period deferred tax liability adjustments.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income, as discussed below, includes intercompany revenues and expenses that are eliminated in the Consolidated Financial Statements. Certain governance costs are allocated to each segment. In addition, direct interest expense and income taxes are included in segment income. Operating segments are determined based on information used by the chief operating decision-maker in deciding how to allocate resources and evaluate the performance of the business. Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets as presented in the tables that follow exclude all intercompany assets. Duke Energy Due to the Piedmont acquisition and the sale of International Energy in the fourth quarter of 2016, Duke Energy's segment structure has been realigned to include the following segments: Electric Utilities and Infrastructure, Gas Utilities and Infrastructure and Commercial Renewables. Prior period information has been recast to conform to the current segment structure. See Note 2 for further information on the Piedmont and International Energy transactions. Electric Utilities and Infrastructure includes Duke Energy's regulated electric utilities in the Carolinas, Florida and the Midwest. The regulated electric utilities conduct operations through the Subsidiary Registrants that are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. Electric Utilities and Infrastructure also includes Duke Energy's commercial electric transmission infrastructure investments. Gas Utilities and Infrastructure contains Piedmont, Duke Energy's natural gas local distribution companies in Ohio and Kentucky, and Duke Energy's natural gas storage and pipeline investments. Gas Utilities and Infrastructure's operations are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. Commercial Renewables is primarily comprised of nonregulated utility scale wind and solar generation assets located throughout the U.S. In December 2016, Duke Energy closed on the sale of the International Disposal Group, which includes the former International Energy business segment, excluding the equity method investment in NMC. Results of the International Disposal Group are presented within Discontinued Operations for all periods and results of NMC are presented within Other for all periods, as described below. See Note 2, "Acquisitions and Dispositions" for additional information related to the sale. The remainder of Duke Energy’s operations is presented as Other, which is primarily comprised of unallocated corporate interest expense, unallocated corporate costs, contributions to the Duke Energy Foundation and the operations of Duke Energy’s wholly owned captive insurance subsidiary, Bison Insurance Company Limited (Bison). As discussed above, Other also includes Duke Energy's 25 percent interest in NMC, a large regional producer of methyl tertiary butyl ether (MTBE) located in Saudi Arabia. The investment in NMC is accounted for under the equity method of accounting. Year Ended December 31, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,336 $ 875 $ 484 $ 22,695 $ 48 $ — $ 22,743 Intersegment Revenues 30 26 — 56 69 (125 ) — Total Revenues $ 21,366 $ 901 $ 484 $ 22,751 $ 117 $ (125 ) $ 22,743 Interest Expense $ 1,136 $ 46 $ 53 $ 1,235 $ 693 $ (12 ) $ 1,916 Depreciation and amortization 2,897 115 130 3,142 152 — 3,294 Equity in earnings (losses) of unconsolidated affiliates (a) 5 19 (82 ) (58 ) 43 — (15 ) Income tax expense (benefit) 1,672 90 (160 ) 1,602 (446 ) — 1,156 Segment income (loss) (b)(c) 3,040 152 23 3,215 (645 ) 1 2,571 Add back noncontrolling interest component 7 Loss from discontinued operations, net of tax (d) (408 ) Net income $ 2,170 Capital investments expenditures and acquisitions (e) $ 6,649 $ 5,519 $ 857 $ 13,025 $ 190 $ — $ 13,215 Segment assets 114,993 10,760 4,377 130,130 2,443 188 132,761 (a) Commercial Renewables includes a pretax impairment charge of $71 million . See Note 12 for additional information. (b) Other includes $329 million of after-tax costs to achieve mergers. Refer to Note 2 for additional information on costs related to the Piedmont merger. (c) Other includes after-tax charges of $57 million related to cost savings initiatives. Refer to Note 19 for further information. (d) Includes a loss on sale of the International Disposal Group. Refer to Note 2 for further information. (e) Other includes $26 million of capital investments expenditures related to the International Disposal Group. Gas Utilities and Infrastructure includes the Piedmont acquisition of $5 billion . Refer to Note 2 for more information on the Piedmont acquisition. Year Ended December 31, 2015 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,489 $ 536 $ 286 $ 22,311 $ 60 $ — $ 22,371 Intersegment Revenues 32 5 — 37 75 (112 ) — Total Revenues $ 21,521 $ 541 $ 286 $ 22,348 $ 135 $ (112 ) $ 22,371 Interest Expense $ 1,074 $ 25 $ 44 $ 1,143 $ 393 $ (9 ) $ 1,527 Depreciation and amortization 2,735 79 104 2,918 135 — 3,053 Equity in earnings (losses) of unconsolidated affiliates (2 ) 1 (6 ) (7 ) 76 — 69 Income tax expense (benefit) 1,602 44 (128 ) 1,518 (262 ) — 1,256 Segment income (loss) (a)(b)(c) 2,819 73 52 2,944 (299 ) — 2,645 Add back noncontrolling interest component 9 Income from discontinued operations, net of tax (d) 177 Net income $ 2,831 Capital investments expenditures and acquisitions (e) $ 6,852 $ 234 $ 1,019 $ 8,105 $ 258 $ — $ 8,363 Segment assets (f) 109,097 2,637 3,861 115,595 5,373 188 121,156 (a) Electric Utilities and Infrastructure includes an after-tax charge of $58 million related to the Edwardsport settlement. Refer to Note 4 for further information. (b) Other includes $60 million of after-tax costs to achieve mergers. (c) Other includes after-tax charges of $77 million related to cost savings initiatives. Refer to Note 19 for further information. (d) Includes the impact of a settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information related to the lawsuit and Note 2 for further information on discontinued operations. (e) Other includes capital investment expenditures of $45 million related to the International Disposal Group. (f) Other includes Assets Held for Sale balances related to the International Disposal Group. Refer to Note 2 for further information. Year Ended December 31, 2014 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,655 $ 573 $ 235 $ 22,463 $ 46 $ — $ 22,509 Intersegment Revenues 36 5 1 42 70 (112 ) — Total Revenues $ 21,691 $ 578 $ 236 $ 22,505 $ 116 $ (112 ) $ 22,509 Interest Expense $ 1,057 $ 37 $ 50 $ 1,144 $ 409 $ (24 ) $ 1,529 Depreciation and amortization 2,686 73 90 2,849 120 — 2,969 Equity in earnings (losses) of unconsolidated affiliates (1 ) — 8 7 123 — 130 Income tax expense (benefit) 1,582 45 (88 ) 1,539 (314 ) — 1,225 Segment income (loss) (a)(b) 2,714 80 53 2,847 (332 ) 18 2,533 Add back noncontrolling interest component 5 Loss from discontinued operations, net of tax (c) (649 ) Net income $ 1,889 Capital investments expenditures and acquisitions (d) $ 4,642 $ 121 $ 514 $ 5,277 $ 251 $ — $ 5,528 Segment assets (e) 104,119 2,512 2,981 109,612 10,755 190 120,557 (a) Other includes a $94 million pretax impairment charge related to Ohio Valley Electric Corporation (OVEC) and costs to achieve mergers. (b) Electric Utilities and Infrastructure includes pretax charges of $102 million related to the criminal investigation of the Dan River coal ash spill. See Note 5 for additional information. (c) Includes an impairment of the Midwest Generation Disposal Group. Refer to Note 2 for further information. (d) Other includes $67 million of capital investments expenditures and acquisitions of the International Disposal Group. (e) Other includes Assets Held for Sale balances related to the International Disposal Group and Midwest Generation Disposal Group. Refer to Note 2 for further information. Geographical Information For the years ended December 31, 2016, 2015 and 2014, all assets and revenues are within the U.S. Products and Services The following table summarizes revenues of the reportable segments by type. Retail Wholesale Retail Total (in millions) Electric Electric Natural Gas Other Revenues 2016 Electric Utilities and Infrastructure $ 18,338 $ 2,095 $ — $ 933 $ 21,366 Gas Utilities and Infrastructure — — 871 30 901 Commercial Renewables — 303 — 181 484 Total Reportable Segments $ 18,338 $ 2,398 $ 871 $ 1,144 $ 22,751 2015 Electric Utilities and Infrastructure $ 18,695 $ 2,014 $ — $ 812 $ 21,521 Gas Utilities and Infrastructure — — 546 (5 ) 541 Commercial Renewables — 245 — 41 286 Total Reportable Segments $ 18,695 $ 2,259 $ 546 $ 848 $ 22,348 2014 Electric Utilities and Infrastructure $ 19,007 $ 1,879 $ — $ 805 $ 21,691 Gas Utilities and Infrastructure — — 571 7 578 Commercial Renewables — 236 — — 236 Total Reportable Segments $ 19,007 $ 2,115 $ 571 $ 812 $ 22,505 Duke Energy Ohio Duke Energy Ohio has two reportable operating segments, Electric Utilities and Infrastructure and Gas Utilities and Infrastructure. Electric Utilities and Infrastructure transmits and distributes electricity in portions of Ohio and generates, distributes and sells electricity in portions of Kentucky. Gas Utilities and Infrastructure transports and sells natural gas in portions of Ohio and northern Kentucky. It conducts operations primarily through Duke Energy Ohio and its wholly owned subsidiary, Duke Energy Kentucky. Other is primarily comprised of governance costs allocated by its parent, Duke Energy, and revenues and expenses related to Duke Energy Ohio's contractual arrangement to buy power from OVEC's power plants. For additional information on related party transactions refer to Note 13 . All of Duke Energy Ohio’s revenues are generated domestically and its long-lived assets are all in the U.S. Year Ended December 31, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,410 $ 503 $ 1,913 $ 31 $ — $ 1,944 Interest expense $ 58 $ 27 $ 85 $ 1 $ — $ 86 Depreciation and amortization 151 80 231 2 — 233 Income tax expense (benefit) 55 44 99 (21 ) — 78 Segment income (loss) 154 77 231 (39 ) — 192 Income from discontinued operations, net of tax 36 Net income $ 228 Capital expenditures $ 322 $ 154 $ 476 $ — $ — $ 476 Segment assets 4,782 2,696 7,478 62 (12 ) 7,528 Year Ended December 31, 2015 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,331 $ 541 $ 1,872 $ 33 $ — $ 1,905 Interest expense $ 53 $ 25 $ 78 $ 1 $ — $ 79 Depreciation and amortization 147 79 226 1 — 227 Income tax expense (benefit) 59 45 104 (23 ) — 81 Segment income (loss) 118 73 191 (41 ) (1 ) 149 Income from discontinued operations, net of tax 23 Net income $ 172 Capital expenditures $ 264 $ 135 $ 399 $ — $ — $ 399 Segment assets 4,534 2,516 7,050 56 (9 ) 7,097 Year Ended December 31, 2014 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,317 $ 578 $ 1,895 $ 19 $ (1 ) $ 1,913 Interest expense $ 43 $ 37 $ 80 $ 5 $ 1 $ 86 Depreciation and amortization 138 73 211 3 — 214 Income tax expense (benefit) 71 45 116 (73 ) — 43 Segment income (loss) (a) 122 80 202 (133 ) (1 ) 68 Loss from discontinued operations, net of tax (b) (563 ) Net loss $ (495 ) Capital expenditures $ 193 $ 107 $ 300 $ 22 $ — $ 322 Segment assets (c) 4,428 2,487 6,915 3,321 (243 ) 9,993 (a) Other includes a $94 million pretax impairment charge related to OVEC. (b) Includes an impairment of the Midwest Generation Disposal Group. Refer to Note 2 for further information. (c) Other includes Assets Held for Sale balances related to the Midwest Generation Disposal Group. Refer to Note 2 for further information. DUKE ENERGY CAROLINAS, PROGRESS ENERGY, DUKE ENERGY PROGRESS, DUKE ENERGY FLORIDA AND DUKE ENERGY INDIANA The remaining Subsidiary Registrants each have one reportable operating segment, Electric Utilities and Infrastructure, which generates, transmits, distributes and sells electricity. The remainder of each company’s operations is classified as Other. While not considered a reportable segment for any of these companies, Other consists of certain unallocated corporate costs. Other for Progress Energy also includes interest expense on corporate debt instruments of $221 million , $240 million and $241 million for the years ended December 31, 2016 , 2015 and 2014 . The following table summarizes the net loss for Other for each of these entities. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas $ (104 ) $ (95 ) $ (79 ) Progress Energy (200 ) (159 ) (190 ) Duke Energy Progress (56 ) (32 ) (31 ) Duke Energy Florida (23 ) (16 ) (19 ) Duke Energy Indiana (13 ) (10 ) (11 ) The assets of Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana are substantially all included within the Electric Utilities and Infrastructure segment at December 31, 2016 , 2015 and 2014 .

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS REGULATORY ASSETS AND LIABILITIES The Duke Energy Registrants record regulatory assets and liabilities that result from the ratemaking process. See Note 1 for further information. The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Assets AROs – coal ash $ 3,761 $ 1,536 $ 1,830 $ 1,822 $ 8 $ 12 $ 276 AROs – nuclear and other 684 9 569 275 294 — — Accrued pension and OPEB 2,387 481 882 423 458 135 222 Retired generation facilities 534 39 422 165 257 — 73 Debt fair value adjustment 1,313 — — — — — — Net regulatory asset related to income taxes 894 484 231 7 224 63 119 Storm cost deferrals 153 — 148 148 — 5 — Nuclear asset securitized balance, net 1,193 — 1,193 — 1,193 — — Hedge costs and other deferrals 217 93 91 66 25 7 26 Derivatives – gas supply contracts 187 — — — — — — Demand side management (DSM)/Energy efficiency (EE) 407 122 278 263 15 6 — Grid Modernization 65 — — — — 65 — Vacation accrual 196 76 38 38 — 4 10 Deferred fuel and purchased power 156 — 111 24 87 5 40 Nuclear deferral 226 92 134 38 96 — — Post-in-service carrying costs and deferred operating expenses 413 70 42 42 — 20 281 Gasification services agreement buyout 8 — — — — — 8 Transmission expansion obligation 71 — — — — 71 — Manufactured gas plant (MGP) 99 — — — — 99 — Advanced metering infrastructure 218 172 — — — — 46 NCEMPA deferrals 51 — 51 51 — — — East Bend deferrals 32 — — — — 32 — Other 636 223 103 69 36 33 121 Total regulatory assets 13,901 3,397 6,123 3,431 2,693 557 1,222 Less: current portion 1,023 238 401 188 213 37 149 Total noncurrent regulatory assets $ 12,878 $ 3,159 $ 5,722 $ 3,243 $ 2,480 $ 520 $ 1,073 December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Liabilities Costs of removal $ 6,074 $ 2,476 $ 2,198 $ 1,840 $ 358 $ 212 $ 660 Amounts to be refunded to customers 45 — — — — — 45 Storm reserve 83 22 60 — 60 1 — Accrued pension and OPEB 174 46 — — — 19 72 Deferred fuel and purchased power 192 105 81 64 17 6 — Other 722 352 245 200 44 19 11 Total regulatory liabilities 7,290 3,001 2,584 2,104 479 257 788 Less: current portion 409 161 189 158 31 21 40 Total noncurrent regulatory liabilities $ 6,881 $ 2,840 $ 2,395 $ 1,946 $ 448 $ 236 $ 748 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Assets AROs – coal ash $ 2,555 $ 1,120 $ 1,394 $ 1,386 $ 8 $ 4 $ 37 AROs – nuclear and other 838 104 487 195 292 — — Accrued pension and OPEB 2,151 479 807 366 441 139 220 Retired generation facilities 509 49 409 179 230 — 51 Debt fair value adjustment 1,191 — — — — — — Net regulatory asset related to income taxes 1,075 564 318 106 212 55 120 Nuclear asset securitizable balance, net 1,237 — 1,237 — 1,237 — — Hedge costs and other deferrals 571 127 410 171 239 7 27 DSM/EE 340 80 250 237 13 10 — Grid Modernization 68 — — — — 68 — Vacation accrual 192 79 38 38 — 5 10 Deferred fuel and purchased power 151 21 129 93 36 1 — Nuclear deferral 245 107 138 62 76 — — Post-in-service carrying costs and deferred operating expenses 383 97 38 38 — 21 227 Gasification services agreement buyout 32 — — — — — 32 Transmission expansion obligation 72 — — — — 72 — MGP 104 — — — — 104 — NCEMPA deferrals 21 — 21 21 — — — East Bend deferrals 16 — — — — 16 — Other 499 244 121 82 39 31 94 Total regulatory assets 12,250 3,071 5,797 2,974 2,823 533 818 Less: current portion 877 305 362 264 98 36 102 Total noncurrent regulatory assets $ 11,373 $ 2,766 $ 5,435 $ 2,710 $ 2,725 $ 497 $ 716 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Liabilities Costs of removal $ 5,329 $ 2,413 $ 2,078 $ 1,725 $ 353 $ 222 $ 616 Amounts to be refunded to customers 71 — — — — — 71 Storm reserve 150 24 125 — 125 1 — Accrued pension and OPEB 288 68 51 25 26 21 83 Deferred fuel and purchased power 311 55 255 58 197 1 — Other 506 281 164 155 8 12 46 Total regulatory liabilities 6,655 2,841 2,673 1,963 709 257 816 Less: current portion 400 39 286 85 200 12 62 Total noncurrent regulatory liabilities $ 6,255 $ 2,802 $ 2,387 $ 1,878 $ 509 $ 245 $ 754 Descriptions of regulatory assets and liabilities, summarized in the tables above, as well as their recovery and amortization periods follow. Items are excluded from rate base unless otherwise noted. AROs – coal ash. Represents regulatory assets including deferred depreciation and accretion related to the legal obligation to close ash basins. The costs are deferred until recovery treatment has been determined. The recovery period for these costs has yet to be established. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Ohio earn a debt return on their expenditures. See Notes 1 and 9 for additional information. AROs – nuclear and other. Represents regulatory assets, including deferred depreciation and accretion, related to legal obligations associated with the future retirement of property, plant and equipment, excluding amounts related to coal ash. The AROs relate primarily to decommissioning nuclear power facilities. The amounts also include certain deferred gains on NDTF investments. The recovery period for costs related to nuclear facilities runs through the decommissioning period of each nuclear unit, the latest of which is currently estimated to be 2086. See Notes 1 and 9 for additional information. Accrued pension and OPEB. Accrued pension and other post-retirement benefit obligations (OPEB) represent regulatory assets and liabilities related to each of the Duke Energy Registrants’ respective shares of unrecognized actuarial gains and losses and unrecognized prior service cost and credit attributable to Duke Energy’s pension plans and OPEB plans. The regulatory asset or liability is amortized with the recognition of actuarial gains and losses and prior service cost and credit to net periodic benefit costs for pension and OPEB plans. The accrued pension and OPEB regulatory asset is expected to be recovered primarily over average remaining service periods of active employees covered by the benefit plans, which is approximately 9 years . See Note 21 for additional detail. Retired generation facilities. Duke Energy Carolinas earns a return on the outstanding retail balance with recovery periods ranging from one to six years . Duke Energy Progress earns a return on the outstanding balance with recovery over a period of 10 years beginning in 2013 for retail purposes and over the longer of 10 years or the previously estimated planned retirement date for wholesale purposes. Duke Energy Indiana earns a return on the outstanding balances and the costs are included in rate base. Duke Energy Indiana’s recovery period will be determined in the next general rate case. Duke Energy Florida earns a full return on a portion of the regulatory asset related to the retired nuclear plant currently recovered in the nuclear cost recovery clause (NCRC), with the remaining portion earning a reduced return. Duke Energy Florida’s recovery period varies. Debt fair value adjustment. Purchase accounting adjustments recorded to state the carrying value of Progress Energy and Piedmont at fair value in connection with the 2012 and 2016 mergers, respectively. Amount is amortized over the life of the related debt. Net regulatory asset related to income taxes. Regulatory assets principally associated with the depreciation and recovery of AFUDC equity. Amounts have no impact on rate base as regulatory assets are offset by deferred tax liabilities. The recovery period is over the life of the associated assets. Amounts for all registrants include regulatory liabilities related to the gross up of federal ITCs. Amounts for Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress include regulatory liabilities related to the change in the North Carolina corporate tax rate discussed in Note 22. Storm cost deferrals. Represents deferred incremental costs incurred related to extraordinary weather-related events, primarily damage resulting from Hurricane Matthew in the fourth quarter of 2016. The recovery period is unknown. Nuclear asset securitizable balance, net. Represents the balance associated with Crystal River Unit 3 retirement approved for recovery by the FPSC on September 15, 2015, and the upfront financing costs securitized in 2016 with issuance of the associated bonds. The regulatory asset balance is net of the AFUDC equity portion. The recovery period is through 2036. Hedge costs and other deferrals. Amounts relate to unrealized gains and losses on derivatives recorded as a regulatory asset or liability, respectively, until the contracts are settled. The recovery period varies for these costs and currently extends to 2048. Derivatives – gas supply contracts held for utility operations . Represents costs for certain long-dated, fixed quantity forward gas supply contracts which are recoverable through Piedmont's PGA clauses. DSM/EE. The recovery period varies for these costs, with some currently unknown. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are required to pay interest on the outstanding liability balance. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida collect a return on DSM/EE investments. Grid Modernization. Duke Energy Ohio amounts represent deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service. Recovery period is generally one year for depreciation and operating expenses. Recovery for post-in-service carrying costs is over the life of the assets. Duke Energy Ohio is earning a return on these costs. Vacation accrual. Generally recovered within one year. Duke Energy Carolinas earns a return on the North Carolina balance. Deferred fuel and purchased power. Represents certain energy-related costs that are recoverable or refundable as approved by the applicable regulatory body. Duke Energy Florida amount includes capacity costs. Duke Energy Florida earns a return on the retail portion of under-recovered costs. Duke Energy Ohio earns a return on under-recovered costs. Duke Energy Florida and Duke Energy Ohio pay interest on over-recovered costs. Duke Energy Carolinas and Duke Energy Progress amounts include certain purchased power costs in both North Carolina and South Carolina and costs of distributed energy resource programs in South Carolina. Duke Energy Carolinas and Duke Energy Progress pay interest on over-recovered costs in North Carolina. Recovery period is generally over one year. Duke Energy Indiana recovery period is quarterly. Nuclear deferral. Includes (i) amounts related to levelizing nuclear plant outage costs at Duke Energy Carolinas and Duke Energy Progress in North Carolina and South Carolina, which allows for the recognition of nuclear outage expenses over the refueling cycle rather than when the outage occurs, resulting in the deferral of operations and maintenance costs associated with refueling and (ii) certain deferred preconstruction and carrying costs at Duke Energy Florida as approved by the FPSC, primarily associated with the Levy nuclear project (Levy), with a final true-up to be filed by May 2017. Post-in-service carrying costs and deferred operating expenses. Represents deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service. Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana earn a return on the outstanding balance. For Duke Energy Ohio and Duke Energy Indiana, some amounts are included in rate base. Recovery is over various lives and the latest recovery period is 2083. Gasification services agreement buyout. The IURC authorized Duke Energy Indiana to recover costs incurred to buyout a gasification services agreement, including carrying costs through 2017. Duke Energy Indiana earns a return on this balance. Transmission expansion obligation. Represents transmission expansion obligations related to Duke Energy Ohio’s withdrawal from Midcontinent Independent System Operator, Inc. (MISO). MGP. Represents remediation costs incurred at former MGP sites and the deferral of costs to be incurred at the East End and West End sites through 2019. Costs incurred between 2008 and 2012 are recovered through an approved MGP rider. Recovery of costs incurred after 2012 has been requested but is pending approval from the PUCO. Duke Energy Ohio does not earn a return on these costs. Advanced metering infrastructure (AMI). Duke Energy Carolinas amount represents deferred costs related to the installation of AMI meters and remaining net book value of non-AMI meters to be replaced. Duke Energy Carolinas earns a return on a portion of the costs and the recovery period varies. Duke Energy Indiana amount represents expected future recovery of net book value of electromechanical meters that have been replaced with AMI meters. Duke Energy Indiana expects to recover this asset over a six-year period and the meters will remain in rate base until the next general rate case. NCEMPA deferrals. Represents retail allocated cost deferrals and returns associated with the additional ownership interest in assets acquired from NCEMPA discussed in Note 2. The North Carolina retail allocated costs are generally being recovered over a period of time between three years and the remaining life of the assets purchased through a rider that became effective on December 1, 2015. The South Carolina retail allocated costs will be amortized over an average of 24 years beginning January 2017 are earning a return. East Bend deferrals. Represents both deferred operating expenses and deferred depreciation as well as carrying costs on the portion of East Bend Generating Station (East Bend) that was acquired from Dayton Power and Light and that had been previously operated as a jointly owned facility. Recovery will not commence until resolution of the next electric rate case in Kentucky. Duke Energy Ohio is earning a return on these deferred costs. Costs of removal. Represents funds received from customers to cover the future removal of property, plant and equipment from retired or abandoned sites as property is retired. Also includes certain deferred gains on NDTF investments. Amounts to be refunded to customers. Represents required rate reductions to retail customers by the applicable regulatory body. The period of refund for Duke Energy Indiana is through 2018. Storm reserve. Duke Energy Carolinas and Duke Energy Florida are allowed to petition the PSCSC and FPSC, respectively, to seek recovery of incremental or allowable costs incurred for named storms. Funds are used to offset future incurred costs. RESTRICTIONS ON THE ABILITY OF CERTAIN SUBSIDIARIES TO MAKE DIVIDENDS, ADVANCES AND LOANS TO DUKE ENERGY As a condition to the approval of merger transactions, the NCUC, PSCSC, PUCO, KPSC and IURC imposed conditions on the ability of Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio, Duke Energy Kentucky, Duke Energy Indiana and Piedmont to transfer funds to Duke Energy through loans or advances, as well as restricted amounts available to pay dividends to Duke Energy. Certain subsidiaries may transfer funds to Duke Energy Corporation Holding Company (the parent) by obtaining approval of the respective state regulatory commissions. These conditions imposed restrictions on the ability of the public utility subsidiaries to pay cash dividends as discussed below. Duke Energy Progress and Duke Energy Florida also have restrictions imposed by their first mortgage bond indentures and Articles of Incorporation which, in certain circumstances, limit their ability to make cash dividends or distributions on common stock. Amounts restricted as a result of these provisions were not material at December 31, 2016 . Additionally, certain other subsidiaries of Duke Energy have restrictions on their ability to dividend, loan or advance funds to Duke Energy due to specific legal or regulatory restrictions, including, but not limited to, minimum working capital and tangible net worth requirements. The restrictions discussed below were less than 25 percent of Duke Energy's net assets at December 31, 2016 . Duke Energy Carolinas Duke Energy Carolinas must limit cumulative distributions subsequent to mergers to (i) the amount of retained earnings on the day prior to the closing of the mergers, plus (ii) any future earnings recorded. Duke Energy Progress Duke Energy Progress must limit cumulative distributions subsequent to the mergers between Duke Energy and Progress Energy and Duke Energy and Piedmont to (i) the amount of retained earnings on the day prior to the closing of the respective mergers, plus (ii) any future earnings recorded. Duke Energy Ohio Duke Energy Ohio will not declare and pay dividends out of capital or unearned surplus without the prior authorization of the PUCO. Duke Energy Ohio received FERC and PUCO approval to pay dividends from its equity accounts that are reflective of the amount that it would have in its retained earnings account had push-down accounting for the Cinergy Corp. (Cinergy) merger not been applied to Duke Energy Ohio’s balance sheet. The conditions include a commitment from Duke Energy Ohio that equity, adjusted to remove the impacts of push-down accounting, will not fall below 30 percent of total capital. Duke Energy Kentucky is required to pay dividends solely out of retained earnings and to maintain a minimum of 35 percent equity in its capital structure. Duke Energy Indiana Duke Energy Indiana must limit cumulative distributions subsequent to the merger between Duke Energy and Cinergy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded. In addition, Duke Energy Indiana will not declare and pay dividends out of capital or unearned surplus without prior authorization of the IURC. Piedmont Piedmont must limit cumulative distributions subsequent to the acquisition of Piedmont by Duke Energy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded. RATE RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO, TRA and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects. Duke Energy Carolinas and Duke Energy Progress Ash Basin Closure Costs Deferral On July 13, 2016, in response to a joint petition of Duke Energy Carolinas and Duke Energy Progress, the PSCSC issued an accounting order for the deferment into a regulatory account of certain costs incurred in connection with federal and state environmental remediation requirements related to the permanent closure of ash basins and other ash storage units at coal-fired generating facilities that have provided or are providing generation to customers located in South Carolina. The decision allows for ash basin closure expenses to be partially offset with excess regulatory liability amounts from the deferral of nuclear decommissioning costs that are collected from South Carolina retail customers and for Duke Energy Progress to partially offset incurred ash basin closure costs with costs of removal amounts collected from customers. The PSCSC's ruling does not change retail rates or the tariff amounts and does not limit the ability of interested parties to challenge the reasonableness of expenditures in subsequent proceedings. In connection with Duke Energy Progress' base rate case filed in July 2016, in December 2016, the PSCSC approved recovery of coal ash costs incurred from January 1, 2015, through June 30, 2016, over a 15 -year period and ongoing deferral of future ash basin closure costs incurred from July 1, 2016, until its next base rate case in South Carolina. On December 30, 2016, Duke Energy Carolinas and Duke Energy Progress filed a joint petition with the NCUC seeking an accounting order authorizing deferral of certain costs incurred in connection with federal and state environmental remediation requirements related to the permanent closure of ash basins and other ash storage units at coal-fired generating facilities that have provided or are providing generation to customers located in North Carolina. Initial comments are due by March 1, 2017, and reply comments are due by March 29, 2017. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. FERC Transmission Return on Equity Complaints On January 7, 2016, a group of transmission service customers filed a complaint with FERC that the rate of return on equity of 10.2 percent in Duke Energy Carolinas' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On the same date, a similar complaint was filed with FERC claiming that the rate of return on equity of 10.8 percent in Duke Energy Progress' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On April 21, 2016, FERC issued an order which consolidated the cases, set a refund effective date of January 7, 2016, and set the consolidated case for settlement and hearing. On June 14, 2016, Duke Energy Carolinas and Duke Energy Progress reached a settlement agreement in principle to reduce the return on equity for both companies to 10 percent . On November 21, 2016, the FERC approved the settlement agreement resolving the complaints. The Impact on results of operations, cash flows and the financial position of Duke Energy Carolinas and Duke Energy Progress will not be material. Duke Energy Carolinas Advanced Metering Infrastructure Deferral On July 12, 2016, the PSCSC issued an accounting order for Duke Energy Carolinas to defer the financial effects of depreciation expense incurred for the installation of AMI meters, the carrying costs on the investment at its weighted average cost of capital (WACC) and the carrying costs on the deferred costs at its WACC not to exceed $45 million . The decision also allows Duke Energy Carolinas to continue to depreciate the non-AMI meters to be replaced. Current retail rates will not change as a result of the decision and the ability of interested parties to challenge the reasonableness of expenditures in subsequent proceedings is not limited. William States Lee Combined Cycle Facility On April 9, 2014, the PSCSC granted Duke Energy Carolinas and North Carolina Electric Membership Corporation (NCEMC) a Certificate of Environmental Compatibility and Public Convenience and Necessity (CECPCN) for the construction and operation of a 750 MW combined-cycle natural gas-fired generating plant at Duke Energy Carolinas' existing William States Lee Generating Station in Anderson, South Carolina. Duke Energy Carolinas began construction in July 2015 and estimates a cost to build of $600 million for its share of the facility, including AFUDC. The project is expected to be commercially available in late 2017. NCEMC will own approximately 13 percent of the project. On July 3, 2014, the South Carolina Coastal Conservation League (SCCL) and Southern Alliance for Clean Energy (SACE) jointly filed a Notice of Appeal with the Court of Appeals of South Carolina (S.C. Court of Appeals) seeking the court's review of the PSCSC's decision, claiming the PSCSC did not properly consider a request related to a proposed solar facility prior to granting approval of the CECPCN. The S.C. Court of Appeals affirmed the PSCSC's decision on February 10, 2016, and on March 24, 2016, denied a request for rehearing filed by SCCL and SACE. On April 21, 2016, SCCL and SACE petitioned the South Carolina Supreme Court for review of the S.C. Court of Appeals decision. Duke Energy Carolinas filed its response on June 13, 2016, and SCCL and SACE filed a reply on June 23, 2016. On September 6, 2016, the Small Business Chamber of Commerce filed a motion for permission to file a brief supporting the environmental intervenors’ position. On September 22, 2016, the South Carolina Supreme Court granted permission for the brief and allowed Duke Energy Carolinas an opportunity to file a response, which was filed on October 3, 2016. Duke Energy Carolinas cannot predict the outcome of this matter. William States Lee III Nuclear Station In December 2007, Duke Energy Carolinas applied to the NRC for combined operating licenses (COLs) for two Westinghouse AP1000 reactors for the proposed William States Lee III Nuclear Station to be located at a site in Cherokee County, South Carolina. The NCUC and PSCSC have concurred with the prudency of Duke Energy Carolinas incurring certain project development and preconstruction costs through several separately issued orders, although full cost recovery is not guaranteed. In December 2016, the NRC issued a COL for each reactor. As of December 31, 2016 , Duke Energy Carolinas has incurred approximately $520 million of costs, including AFUDC, related to the project. These project costs are included in Net property, plant and equipment on Duke Energy Carolinas’ Consolidated Balance Sheets. Duke Energy Carolinas is not required to build the nuclear reactors as result of the COLs being issued. Duke Energy Progress Storm Cost Deferral Filings On December 16, 2016, Duke Energy Progress filed a petition with the NCUC requesting an accounting order to defer certain costs incurred in connection with response to Hurricane Matthew and other significant storms in 2016. Current estimated incremental operation and maintenance and capital costs total approximately $140 million . Additional costs could be incurred in 2017 related to storms in the fourth quarter of 2016. Duke Energy Progress proposes to true-up the total costs quarterly through August 2017. Duke Energy Progress cannot predict the outcome of this matter. On December 16, 2016, Duke Energy Progress filed a petition with the PSCSC requesting an accounting order to defer certain costs incurred related to repairs and restoration of service following Hurricane Matthew. Estimated total restoration costs are approximately $60 million . Actual total costs would be trued-up quarterly through 2017. In January 2017, the PSCSC approved the deferral request and issued an accounting order. South Carolina Rate Case On July 1, 2016, Duke Energy Progress filed an application with the PSCSC requesting an average 14.5 percent increase in retail revenues. The requested rate change would increase annual revenues by approximately $79 million , with a rate of return on equity of 10.75 percent . The increase is designed to recover the cost of investment in new generation infrastructure, environmental expenditures including allocated historical ash basin closure costs and increased nuclear operating costs. Duke Energy Progress has requested new rates to be effective January 1, 2017. On October 19, 2016, Duke Energy Progress, the ORS and intervenors entered into a settlement agreement that was filed with the PSCSC on the same day. Terms of the settlement agreement include an approximate $56 million increase in revenues over a two-year period. An increase of approximately $38 million in revenues was effective January 1, 2017, and an additional increase of approximately $18.5 million in revenues will be effective January 1, 2018. Duke Energy Progress will amortize approximately $18.5 million from the cost of removal reserve in 2017. Other settlement terms include a rate of return on equity of 10.1 percent , recovery of coal ash costs incurred from January 1, 2015, through June 30, 2016, over a 15-year period and ongoing deferral of allocated ash basin closure costs from July 1, 2016, until the next base rate case. The settlement also provides that Duke Energy Progress will not seek an increase in rates in South Carolina to occur prior to 2019, with limited exceptions. In December 2016, the PSCSC approved the settlement and issued an approval order. Western Carolinas Modernization Plan On November 4, 2015, in response to community feedback, Duke Energy Progress announced a revised Western Carolinas Modernization Plan with an estimated cost of $1.1 billion . The revised plan includes retirement of the existing Asheville coal-fired plant, the construction of two 280 MW combined-cycle natural gas plants having dual fuel capability, with the option to build a third natural gas simple cycle unit in 2023 based upon the outcome of initiatives to reduce the region's power demand. The revised plan includes upgrades to existing transmission lines and substations, but eliminates the need for a new transmission line and a new substation associated with the project in South Carolina. The revised plan has the same overall project cost as the original plan and the plans to install solar generation remain unchanged. Duke Energy Progress has also proposed to add a pilot battery storage project. These investments will be made within the next seven years. Duke Energy Progress is also working with the local natural gas distribution company to upgrade an existing natural gas pipeline to serve the natural gas plant. The plan requires various approvals including regulatory approvals in North Carolina. Duke Energy Progress filed for a Certificate of Public Convenience and Necessity (CPCN) with the NCUC for the new natural gas units on January 15, 2016. On March 28, 2016, the NCUC issued an order approving the CPCN for the new combined-cycle natural gas plants, but denying the CPCN for the contingent simple cycle unit without prejudice to Duke Energy Progress to refile for approval in the future. Site preparation activities are underway and construction of these plants is scheduled to begin in early 2017. The plants are expected to be in service by late 2019. Duke Energy Progress plans to file for future approvals related to the proposed solar generation and pilot battery storage project. On May 27, 2016, N.C. Waste Awareness and Reduction Network (NC WARN) and The Climate Times filed a notice of appeal from the CPCN order to the N.C. Court of Appeals. On May 31, 2016, Duke Energy Progress filed a motion to dismiss the notice of appeal with the NCUC due to NC WARN's and The Climate Times' failure to post a required appeal bond. After a series of filings, an NCUC order, petitions to the N.C. Court of Appeals and an evidentiary hearing, on July 8, 2016, the NCUC issued an order setting NC WARN's and The Climate Times' appeal bond at $98 million . On July 28, 2016, NC WARN and The Climate Times filed a notice of appeal and exceptions from the NCUC's July 8, 2016, appeal bond order. On August 2, 2016, the NCUC granted Duke Energy Progress' motion to dismiss NC WARN's and The Climate Times' notice of appeal from the CPCN order due to failure to post the requisite bond. On August 18, 2016, NC WARN and The Climate Times filed a petition with the N.C. Court of Appeals seeking appellate review of the NCUC’s CPCN order, the July 8, 2016, appeal bond order and the August 2, 2016, order dismissing their notice of appeal, which the N.C. Court of Appeals denied on September 6, 2016. On September 19, 2016, the NCUC granted Duke Energy Progress' motion to dismiss NC WARN's and The Climate Times' subsequent appeal of the second bond order dated July 28, 2016, and NC WARN's and The Climate Times' subsequent appeal of the CPCN order and dismissal order dated August 18, 2016. On October 17, 2016, NC WARN and The Climate Times filed another petition for review with the N.C. Court of Appeals asking the court to reverse the CPCN order, the second bond order and the dismissal of their first and second notices of appeal as to the CPCN order. On November 3, 2016, the N.C. Court of Appeals denied NC WARN's and The Climate Times' petition for review. All appeals have been concluded. The carrying value of the 376 MW Asheville coal-fired plant, including associated ash basin closure cos

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES INSURANCE General Insurance The Duke Energy Registrants have insurance and reinsurance coverage either directly or through indemnification from Duke Energy’s captive insurance company, Bison, and its affiliates, consistent with companies engaged in similar commercial operations with similar type properties. The Duke Energy Registrants’ coverage includes (i) commercial general liability coverage for liabilities arising to third parties for bodily injury and property damage; (ii) workers’ compensation; (iii) automobile liability coverage; and (iv) property coverage for all real and personal property damage. Real and personal property damage coverage excludes electric transmission and distribution lines, but includes damages arising from boiler and machinery breakdowns, earthquakes, flood damage and extra expense, but not outage or replacement power coverage. All coverage is subject to certain deductibles or retentions, sublimits, exclusions, terms and conditions common for companies with similar types of operations. The Duke Energy Registrants self-insure their electric transmission and distribution lines against loss due to storm damage and other natural disasters. As discussed further in Note 4 , Duke Energy Florida maintains a storm damage reserve and has a regulatory mechanism to recover the cost of named storms on an expedited basis. The cost of the Duke Energy Registrants’ coverage can fluctuate from year to year reflecting claims history and conditions of the insurance and reinsurance markets. In the event of a loss, terms and amounts of insurance and reinsurance available might not be adequate to cover claims and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered by other sources, could have a material effect on the Duke Energy Registrants’ results of operations, cash flows or financial position. Each company is responsible to the extent losses may be excluded or exceed limits of the coverage available. Nuclear Insurance Duke Energy Carolinas owns and operates the McGuire Nuclear Station (McGuire) and the Oconee Nuclear Station (Oconee) and operates and has a partial ownership interest in the Catawba Nuclear Station (Catawba). McGuire and Catawba each have two reactors. Oconee has three reactors. The other joint owners of Catawba reimburse Duke Energy Carolinas for certain expenses associated with nuclear insurance per the Catawba joint owner agreements. Duke Energy Progress owns and operates the Robinson Nuclear Plant (Robinson), Brunswick and Harris. Robinson and Harris each have one reactor. Brunswick has two reactors. Duke Energy Florida owns Crystal River Unit 3, which has been retired. In the event of a loss, terms and amounts of insurance available might not be adequate to cover property damage and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered by other sources, could have a material effect on Duke Energy Carolinas’, Duke Energy Progress’ and Duke Energy Florida’s results of operations, cash flows or financial position. Each company is responsible to the extent losses may be excluded or exceed limits of the coverage available. Nuclear Liability Coverage The Price-Anderson Act requires owners of nuclear reactors to provide for public nuclear liability protection per nuclear incident up to a maximum total financial protection liability. The maximum total financial protection liability, which is approximately $13.4 billion , is subject to change every five years for inflation and for the number of licensed reactors. Total nuclear liability coverage consists of a combination of private primary nuclear liability insurance coverage and a mandatory industry risk-sharing program to provide for excess nuclear liability coverage above the maximum reasonably available private primary coverage. The United States Congress could impose revenue-raising measures on the nuclear industry to pay claims. Primary Liability Insurance Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida have purchased the maximum reasonably available private primary nuclear liability insurance as required by law, which was $375 million per station. For incidents after January 1, 2017, this primary nuclear liability insurance limit increased to $450 million per station. Excess Liability Program This program provides $13 billion of coverage per incident through the Price-Anderson Act’s mandatory industrywide excess secondary financial protection program of risk pooling. This amount is the product of potential cumulative retrospective premium assessments of $127 million times the current 102 licensed commercial nuclear reactors in the U.S. Under this program, licensees could be assessed retrospective premiums to compensate for public nuclear liability damages in the event of a nuclear incident at any licensed facility in the U.S. Retrospective premiums may be assessed at a rate not to exceed $19 million per year per licensed reactor for each incident. The assessment may be subject to state premium taxes. Nuclear Property and Accidental Outage Coverage Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are members of Nuclear Electric Insurance Limited (NEIL), an industry mutual insurance company, which provides "all risk" property damage, decontamination and premature decommissioning insurance for each station for losses resulting from damage to its nuclear plants, either due to accidents or acts of terrorism. Additionally, NEIL provides some replacement power cost insurance for each station for losses in the event of a major accidental outage at an insured nuclear station. NEIL requires its members to maintain an investment grade credit rating or to ensure collectability of their annual retrospective premium obligation by providing a financial guarantee, letter of credit, deposit premium or other means of assurance. The companies are required each year to report to the NRC the current levels and sources of insurance that demonstrate it possesses sufficient financial resources to stabilize and decontaminate its reactors and reactor station sites in the event of an accident. Pursuant to regulations of the NRC, each company’s property damage insurance policies provide that all proceeds from such insurance be applied, first, to place the plant in a safe and stable condition after a qualifying accident and second, to decontaminate the plant before any proceeds can be used for decommissioning, plant repair or restoration. Losses resulting from acts of terrorism are covered as common occurrences, such that if terrorist acts occur against one or more commercial nuclear power plants insured by NEIL within a 12-month period, they would be treated as one event and the owners of the plants where the act occurred would share one full limit of liability. The full limit of liability is currently $3.2 billion . NEIL sublimits the total aggregate for all of their policies for non-nuclear terrorist events to approximately $1.83 billion . Each nuclear facility has accident property damage, decontamination and premature decommissioning liability insurance from NEIL with limits of $1.5 billion , except for Crystal River Unit 3. Crystal River Unit 3’s limit is $50 million and is on an actual cash value basis. All nuclear facilities except for Catawba and Crystal River Unit 3 also share an additional $1.25 billion nuclear accident insurance limit above their dedicated underlying limit. This shared additional excess limit is not subject to reinstatement in the event of a loss. Catawba has a dedicated $1.25 billion of additional nuclear accident insurance limit above its dedicated underlying limit. Catawba and Oconee also have an additional $750 million of non-nuclear accident property damage limit. All coverages are subject to sublimits and significant deductibles. NEIL’s Accidental Outage policy provides some replacement power cost insurance for losses in the event of a major accident property damage outage of a nuclear unit. Coverage is provided on a weekly limit basis after a significant waiting period deductible and at 100 percent of the available weekly limits for 52 weeks and 80 percent of the available weekly limits for the next 110 weeks. Coverage is provided until these available weekly periods are met where the accidental outage policy limit will not exceed $490 million for McGuire, Catawba, Brunswick and Harris, $464 million for Oconee and $404 million for Robinson. NEIL sublimits the accidental outage recovery to the first 104 weeks of coverage not to exceed $328 million from non-nuclear accidental property damage. Coverage amounts decrease in the event more than one unit at a station is out of service due to a common accident. All coverages are subject to sublimits and significant deductibles. Potential Retroactive Premium Assessments In the event of NEIL losses, NEIL’s board of directors may assess member companies retroactive premiums of amounts up to 10 times their annual premiums for up to six years after a loss. NEIL has never exercised this assessment. The maximum aggregate annual retrospective premium obligations for Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida are $164 million , $104 million and $1 million , respectively. Duke Energy Carolinas' maximum assessment amount includes 100 percent of potential obligations to NEIL for jointly owned reactors. Duke Energy Carolinas would seek reimbursement from the joint owners for their portion of these assessment amounts. ENVIRONMENTAL The Duke Energy Registrants are subject to federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. These regulations can be changed from time to time, imposing new obligations on the Duke Energy Registrants. The following environmental matters impact all of the Duke Energy Registrants. Remediation Activities In addition to the ARO recorded as a result of various environmental regulations, discussed in Note 9, the Duke Energy Registrants are responsible for environmental remediation at various sites. These include certain properties that are part of ongoing operations and sites formerly owned or used by Duke Energy entities. These sites are in various stages of investigation, remediation and monitoring. Managed in conjunction with relevant federal, state and local agencies, remediation activities vary based upon site conditions and location, remediation requirements, complexity and sharing of responsibility. If remediation activities involve joint and several liability provisions, strict liability, or cost recovery or contribution actions, the Duke Energy Registrants could potentially be held responsible for environmental impacts caused by other potentially responsible parties and may also benefit from insurance policies or contractual indemnities that cover some or all cleanup costs. Liabilities are recorded when losses become probable and are reasonably estimable. The total costs that may be incurred cannot be estimated because the extent of environmental impact, allocation among potentially responsible parties, remediation alternatives and/or regulatory decisions have not yet been determined at all sites. Additional costs associated with remediation activities are likely to be incurred in the future and could be significant. Costs are typically expensed as Operation, maintenance and other in the Consolidated Statements of Operations unless regulatory recovery of the costs is deemed probable. The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Other within Deferred Credits and Other Liabilities on the Consolidated Balance Sheets. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2013 $ 74 $ 11 $ 27 $ 8 $ 19 $ 27 $ 7 Provisions/adjustments 32 (1 ) 1 4 (3 ) 28 4 Cash reductions (14 ) — (11 ) (7 ) (4 ) (1 ) (1 ) Balance at December 31, 2014 92 10 17 5 12 54 10 Provisions/adjustments 11 1 4 — 4 1 5 Cash reductions (9 ) (1 ) (4 ) (2 ) (2 ) (1 ) (3 ) Balance at December 31, 2015 94 10 17 3 14 54 12 Provisions/adjustments 19 4 7 2 4 7 1 Cash reductions (15 ) (4 ) (6 ) (2 ) (4 ) (2 ) (3 ) Balance at December 31, 2016 $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10 Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 69 Duke Energy Carolinas 22 Duke Energy Ohio 36 Duke Energy Indiana 7 North Carolina and South Carolina Ash Basins In February 2014, a break in a stormwater pipe beneath an ash basin at Duke Energy Carolinas’ retired Dan River Steam Station caused a release of ash basin water and ash into the Dan River. Duke Energy Carolinas estimates 30,000 to 39,000 tons of ash and 24 million to 27 million gallons of basin water were released into the river. In July 2014, Duke Energy completed remediation work identified by the EPA and continues to cooperate with the EPA's civil enforcement process. Future costs related to the Dan River release, including future state or federal civil enforcement proceedings, future regulatory directives, natural resources damages, future claims or litigation and long-term environmental impact costs, cannot be reasonably estimated at this time. The North Carolina Department of Environmental Quality (NCDEQ) has historically assessed Duke Energy Carolinas and Duke Energy Progress with Notice of Violations (NOV) for violations that were most often resolved through satisfactory corrective actions and minor, if any, fines or penalties. Subsequent to the Dan River ash release, Duke Energy Carolinas and Duke Energy Progress have been served with a higher level of NOVs, including assessed penalties for violations at L.V. Sutton Combined Cycle Plant (Sutton) and Dan River Steam Station. Duke Energy Carolinas and Duke Energy Progress cannot predict whether the NCDEQ will assess future penalties related to existing unresolved NOVs and if such penalties would be material. See "NCDEQ Notices of Violation" section below for additional discussion. LITIGATION Duke Energy Duke Energy no longer has exposure to litigation matters related to the International Energy Disposal Group as a result of the divestiture of the business in December 2016. See Note 2 for additional information related to the sale of International Energy. Ash Basin Shareholder Derivative Litigation Five shareholder derivative lawsuits were filed in Delaware Chancery Court relating to the release at Dan River and to the management of Duke Energy’s ash basins. On October 31, 2014, the five lawsuits were consolidated in a single proceeding titled In Re Duke Energy Corporation Coal Ash Derivative Litigation . On December 2, 2014, plaintiffs filed a Corrected Verified Consolidated Shareholder Derivative Complaint (Consolidated Complaint). The Consolidated Complaint names as defendants several current and former Duke Energy officers and directors (collectively, the “Duke Energy Defendants”). Duke Energy is named as a nominal defendant. The Consolidated Complaint alleges the Duke Energy Defendants breached their fiduciary duties by failing to adequately oversee Duke Energy’s ash basins and that these breaches of fiduciary duty may have contributed to the incident at Dan River and continued thereafter. The lawsuit also asserts claims against the Duke Energy Defendants for corporate waste (relating to the money Duke Energy has spent and will spend as a result of the fines, penalties and coal ash removal) and unjust enrichment (relating to the compensation and director remuneration that was received despite these alleged breaches of fiduciary duty). The lawsuit seeks both injunctive relief against Duke Energy and restitution from the Duke Energy Defendants. On January 21, 2015, the Duke Energy Defendants filed a Motion to Stay and an alternative Motion to Dismiss. On August 31, 2015, the court issued an order staying the case which was lifted on March 24, 2016. On April 22, 2016, plaintiffs filed an Amended Verified Consolidated Shareholder Derivative Complaint (Amended Complaint) making the same allegations as in the Consolidated Complaint. The Duke Energy Defendants filed a motion to dismiss the Amended Complaint on June 21, 2016. On December 14, 2016, the Delaware Chancery Court entered an order dismissing the Amended Complaint. Plaintiffs filed an appeal to the Delaware Supreme Court on January 9, 2017. Opening briefs were due by February 24, 2017, and a date for oral argument has not been set. On March 5, 2015, shareholder Judy Mesirov filed a shareholder derivative complaint (Mesirov Complaint) in North Carolina state court. The lawsuit, styled Mesirov v. Good , was similar to the consolidated derivative action pending in Delaware Chancery Court and was filed against the same current directors and former directors and officers as the Delaware litigation. Duke Energy Corporation, Duke Energy Progress and Duke Energy Carolinas were named as nominal defendants. The Mesirov Complaint alleged that the Duke Energy Board of Directors was aware of Clean Water Act (CWA) compliance issues and failures to maintain structures in ash basins, but that the Board of Directors did not require Duke Energy Carolinas and Duke Energy Progress to take action to remedy deficiencies. The Mesirov Complaint further alleged that the Board of Directors sanctioned activities to avoid compliance with the law by allowing improper influence of the NCDEQ to minimize regulation and by opposing previously anticipated citizen suit litigation. The Mesirov Complaint sought corporate governance reforms and damages relating to costs associated with the Dan River release, remediation of ash basins that are out of compliance with the CWA and defending and payment of fines, penalties and settlements relating to criminal and civil investigations and lawsuits. On July 5, 2016, the plaintiff filed a Notice of Voluntary Dismissal Without Prejudice, closing this matter. In addition to the above derivative complaints, in 2014, Duke Energy received two shareholder litigation demand letters. The letters alleged that the members of the Board of Directors and certain officers breached their fiduciary duties by allowing the company to illegally dispose of and store coal ash pollutants. One of the letters also alleged a breach of fiduciary duty in the decision-making relating to the leadership changes following the close of the Progress Energy merger in July 2012. By letter dated September 4, 2015, attorneys for the shareholders were informed that, on the recommendation of the Demand Review Committee formed to consider such matters, the Board of Directors concluded not to pursue potential claims against individuals. One of the shareholders, Mitchell Pinsly, sent a formal demand for records and Duke Energy has responded to this request. On October 30, 2015, shareholder Saul Bresalier filed a shareholder derivative complaint (Bresalier Complaint) in the U.S. District Court for the District of Delaware. The lawsuit alleges that several current and former Duke Energy officers and directors (Bresalier Defendants) breached their fiduciary duties in connection with coal ash environmental issues, the post-merger change in Chief Executive Officer (CEO) and oversight of political contributions. Duke Energy is named as a nominal defendant. The Bresalier Complaint contends that the Demand Review Committee failed to appropriately consider the shareholder’s earlier demand for litigation and improperly decided not to pursue claims against the Bresalier Defendants. The Bresalier Defendants filed a Motion to Dismiss the Bresalier litigation on January 15, 2016. In lieu of a response to the Motion to Dismiss, the plaintiff filed a Motion to Convert the Bresalier Defendants' Motion to Dismiss into a Motion for Summary Judgment and also for limited discovery. Following a hearing on June 15, 2016, the court denied the plaintiff's Motion to Convert and is requiring the parties to complete briefing on the Bresalier Defendants' Motion to Dismiss. On July 29, 2016, the Bresalier Defendants filed an Amended Motion to Dismiss. Oral argument on the Amended Motion to Dismiss was heard on December 20, 2016. As discussed below, an agreement-in-principle has been reached to settle the merger related claims in the Bresalier Complaint. It is not possible to predict whether Duke Energy will incur any liability or to estimate the damages, if any, it might incur in connection with these matters. Progress Energy Merger Shareholder Litigation Duke Energy, the 11 members of the Board of Directors who were also members of the pre-merger Board of Directors (Legacy Duke Energy Directors) and certain Duke Energy officers were defendants in a purported securities class action lawsuit (Nieman v. Duke Energy Corporation, et al) . This lawsuit consolidated three lawsuits originally filed in July 2012. The plaintiffs alleged federal Securities Act of 1933 and Securities Exchange Act of 1934 (Exchange Act) claims based on allegations of materially false and misleading representations and omissions in the Registration Statement filed on July 7, 2011, and purportedly incorporated into other documents, all in connection with the post-merger change in CEO. On August 15, 2014, the parties reached an agreement in principle to settle the litigation. On March 10, 2015, the parties filed a Stipulation of Settlement and a Motion for Preliminary Approval of the Settlement. Under the terms of the agreement, Duke Energy agreed to pay $146 million to settle the claim. On April 22, 2015, Duke Energy made a payment of $25 million into the settlement escrow account. The remainder of $121 million was paid by insurers into the settlement escrow account. The final order approving the settlement was issued on November 2, 2015, thus closing the matter. On May 31, 2013, the Delaware Chancery Court consolidated four shareholder derivative lawsuits filed in 2012. The Court also appointed a lead plaintiff and counsel for plaintiffs and designated the case as In Re Duke Energy Corporation Derivative Litigation (Merger Chancery Litigation). The lawsuit names as defendants the Legacy Duke Energy Directors. Duke Energy is named as a nominal defendant. The case alleges claims for breach of fiduciary duties of loyalty and care in connection with the post-merger change in CEO. Two shareholder Derivative Complaints, filed in 2012 in federal district court in Delaware, were consolidated as Tansey v. Rogers, et al. The case alleges claims against the Legacy Duke Energy Directors for breach of fiduciary duty and waste of corporate assets, as well as claims under Section 14(a) and 20(a) of the Exchange Act. Duke Energy is named as a nominal defendant. On December 21, 2015, Plaintiff filed a Consolidated Amended Complaint asserting the same claims contained in the original complaints. The Legacy Duke Energy Directors have reached an agreement-in-principle to settle the Merger Chancery Litigation, conditioned on dismissal as well, of the Tansey v. Rogers, et al case and the merger related claims in the Bresalier Complaint discussed above, for a total of $27 million . The entire settlement amount is to be funded by insurance. The settlement amount, less court-approved attorney fees, will be payable to Duke Energy. The settlement is subject to the execution of definitive settlement documents and court approval. Price Reporting Cases Duke Energy Trading and Marketing, LLC (DETM), a non-operating Duke Energy affiliate, was a defendant, along with numerous other energy companies, in four class-action lawsuits and a fifth single-plaintiff lawsuit in a consolidated federal court proceeding in Nevada. Each of these lawsuits contained similar claims that defendants allegedly manipulated natural gas markets by various means, including providing false information to natural gas trade publications and entering into unlawful arrangements and agreements in violation of the antitrust laws of the respective states. Plaintiffs sought damages in unspecified amounts. In February 2016, DETM reached agreements in principle to settle all of the pending lawsuits. Settlement of the single-plaintiff settlement was finalized and paid in March 2016. The proposed settlement of the class-action lawsuits was submitted to the Court and preliminarily approved on January 26, 2017. The Court will consider final approval of the class settlement following notice to the class members. The settlement amounts are not material to Duke Energy. Duke Energy Carolinas and Duke Energy Progress NCDEQ Notice of Violation In August 2014, NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' Sutton Plant. On March 10, 2015, NCDEQ issued a civil penalty of approximately $25 million to Duke Energy Progress for environmental damages related to alleged groundwater contamination at the Sutton Plant. On April 9, 2015, Duke Energy Progress filed a Petition for Contested Case hearing in the Office of Administrative Hearings. In February 2015, NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' Asheville Plant. Duke Energy Progress responded to NCDEQ regarding this NOV. On September 29, 2015, Duke Energy Progress and Duke Energy Carolinas entered into a settlement agreement with NCDEQ resolving all former, current and future groundwater penalties at all Duke Energy Carolinas and Duke Energy Progress coal facilities in North Carolina. Under the agreement, Duke Energy Progress paid approximately $6 million and Duke Energy Carolinas paid approximately $1 million . In addition to these payments, Duke Energy Progress and Duke Energy Carolinas will accelerate remediation actions at the Sutton, Asheville, Belews Creek and H.F. Lee plants. The court entered a consent order resolving the contested case relating to the Sutton Plant and NCDEQ rescinded the NOVs relating to alleged groundwater violations at both the Sutton and Asheville plants. On October 13, 2015, the Southern Environmental Law Center (SELC), representing multiple conservation groups, filed a lawsuit in North Carolina Superior Court seeking judicial review of the order approving the settlement agreement with NCDEQ. The conservation groups contend that the ALJ exceeded his statutory authority in approving a settlement that provided for past, present and future resolution of groundwater issues at facilities which were not at issue in the penalty appeal. On December 18, 2015, Duke Energy Carolinas and Duke Energy Progress filed a Motion to Dismiss the complaint. On February 12, 2016, the ALJ entered a new order clarifying that the dismissal of the contested case only applied to the specific issues before the ALJ in the Petition for Contested Case. On March 10, 2016, the court dismissed the SELC lawsuit based on the ALJ's entry of the new order. On February 8, 2016, the NCDEQ assessed a penalty of approximately $6.8 million , including enforcement costs, against Duke Energy Carolinas related to stormwater pipes and associated discharges at the Dan River Steam Station. Duke Energy Carolinas recorded a charge in December 2015 for this penalty. In March 2016, Duke Energy Carolinas filed an appeal of this penalty. On September 23, 2016, Duke Energy Carolinas entered into a settlement agreement with the NCDEQ, without admission of liability, under which Duke Energy Carolinas agreed to a payment of $6 million to resolve allegations underlying the asserted civil penalty related to the Dan River coal ash release and a March 4, 2016, NOV alleging unpermitted discharges at the facility. NCDEQ State Enforcement Actions In the first quarter of 2013, SELC sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged CWA violations from coal ash basins at two of their coal-fired power plants in North Carolina. The NCDEQ filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The cases have been consolidated and are being heard before a single judge. On August 16, 2013, the NCDEQ filed an enforcement action against Duke Energy Carolinas and Duke Energy Progress related to their remaining plants in North Carolina, alleging violations of the CWA and violations of the North Carolina groundwater standards. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. SELC is representing several environmental groups who have been permitted to intervene in these cases. On July 10, 2015, Duke Energy Carolinas and Duke Energy Progress filed two Motions for Partial Summary Judgment in the case on the basis that there is no longer either a genuine controversy or disputed material facts about the relief for seven of the 14 North Carolina plants with coal ash basins. On September 14, 2015, the court granted the Motions for Partial Summary Judgment pending court approval of the terms through an order. On April 4, 2016, the court issued an order granting Duke Energy Progress' Motion for Partial Summary Judgment for cases involving the H.F. Lee, Cape Fear and Weatherspoon plants. On June 1, 2016, the court issued an order granting Duke Energy Carolinas' and Duke Energy Progress' Motion for Partial Summary Judgment for cases involving the Asheville, Dan River, Riverbend and Sutton plants. The litigation is concluded for these seven plants. Litigation continues for the remaining seven plants. In response to a motion for partial summary judgment on the groundwater claims filed by the environmental groups, on October 17, 2016, Duke Energy Carolinas and Duke Energy Progress filed a cross-motion for partial summary judgment on the groundwater claims. On February 13, 2017, the court issued an order denying both the environmental groups' motion for partial summary judgment and Duke Energy Carolinas and Duke Energy Progress' cross-motion for partial summary judgment. It is not possible to predict any liability or estimate any damages Duke Energy Carolinas or Duke Energy Progress might incur in connection with these matters. Federal Citizens Suits On June 13, 2016, the Roanoke River Basin Association filed a federal citizen suit in the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Mayo Plant. On August 19, 2016, Duke Energy Progress filed a Motion to Dismiss the complaint and a decision is pending. It is not possible to predict whether Duke Energy Progress will incur any liability or to estimate the damages, if any, they might incur in connection with this matter. Five previously filed cases involving the Riverbend, Cape Fear, H.F. Lee, Sutton and Buck plants have been dismissed or settled during 2016. North Carolina Ash Basin Grand Jury Investigation As a result of the Dan River ash basin water release discussed above, NCDEQ issued a NOV and Recommendation of Assessment of Civil Penalties with respect to this matter on February 28, 2014, which the company responded to on March 13, 2014. Duke Energy and certain Duke Energy employees received subpoenas issued by the United States Attorney for the Eastern District of North Carolina in connection with a criminal investigation related to all 14 of the North Carolina facilities with ash basins and the nature of Duke Energy's contacts with NCDEQ with respect to those facilities. This was a multidistrict investigation that also involves state law enforcement authorities. On February 20, 2015, Duke Energy Carolinas, Duke Energy Progress and Duke Energy Business Services LLC (DEBS), a wholly owned subsidiary of Duke Energy, each entered into Plea Agreements in connection with the investigation initiated by the United States Department of Justice Environmental Crimes Section and the United States Attorneys for the Eastern District of North Carolina, the Middle District of North Carolina and the Western District of North Carolina (collectively, USDOJ). On May 14, 2015, the United States District Court for the Eastern District of North Carolina approved the Plea Agreements. Under the Plea Agreements, DEBS and Duke Energy Progress pleaded guilty to four misdemeanor CWA violations related to violations at Duke Energy Progress’ H.F. Lee Steam Electric Plant, Cape Fear Steam Electri

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt and Credit Facilities	DEBT AND CREDIT FACILITIES Summary of Debt and Related Terms The following tables summarize outstanding debt. December 31, 2016 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Unsecured debt, maturing 2017 - 2073 4.30 % $ 17,812 $ 1,150 $ 3,551 $ — $ 150 $ 810 $ 415 Secured debt, maturing 2017 - 2037 2.60 % 3,909 425 1,819 300 1,519 — — First mortgage bonds, maturing 2017 - 2046 (a) 4.61 % 21,879 7,410 10,800 6,425 4,375 1,000 2,669 Capital leases, maturing 2018 - 2051 (b) 4.48 % 1,100 22 285 142 143 7 11 Tax-exempt bonds, maturing 2017 - 2041 (c) 2.84 % 1,053 355 48 48 — 77 572 Notes payable and commercial paper (d) 1.01 % 3,112 — — — — — — Money pool/intercompany borrowings (e) — 300 1,902 150 297 41 150 Fair value hedge carrying value adjustment 6 6 — — — — — Unamortized debt discount and premium, net (f) 1,753 (20 ) (31 ) (16 ) (10 ) (28 ) (9 ) Unamortized debt issuance costs (g) (242 ) (45 ) (104 ) (38 ) (52 ) (7 ) (22 ) Total debt 4.07 % $ 50,382 $ 9,603 $ 18,270 $ 7,011 $ 6,422 $ 1,900 $ 3,786 Short-term notes payable and commercial paper (2,487 ) — — — — — — Short-term money pool/intercompany borrowings — — (729 ) — (297 ) (16 ) — Current maturities of long-term debt (h) (2,319 ) (116 ) (778 ) (452 ) (326 ) (1 ) (3 ) Total long-term debt (h) $ 45,576 $ 9,487 $ 16,763 $ 6,559 $ 5,799 $ 1,883 $ 3,783 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $98 million and $670 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy and Piedmont's commercial paper programs were 14 days and eight days, respectively. (e) Progress Energy amount includes a $1 billion intercompany loan related to the sale of the International Disposal Group. See Note 2 for further discussion of the sale. (f) Duke Energy includes $1,653 million and $197 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (g) Duke Energy includes $53 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (h) Refer to Note 17 for additional information on amounts from consolidated VIEs. December 31, 2015 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Unsecured debt, maturing 2016 - 2073 4.68 % $ 12,960 $ 1,152 $ 3,850 $ — $ 150 $ 765 $ 740 Secured debt, maturing 2016 - 2037 2.37 % 2,361 425 479 254 225 — — First mortgage bonds, maturing 2016 - 2045 (a) 4.74 % 18,980 6,161 9,750 5,975 3,775 750 2,319 Capital leases, maturing 2016 - 2051 (b) 5.39 % 1,335 24 300 144 156 13 14 Tax-exempt bonds, maturing 2017 - 2041 (c) 2.59 % 1,053 355 48 48 — 77 572 Notes payable and commercial paper (d) 0.88 % 4,258 — — — — — — Money pool/intercompany borrowings — 300 1,458 359 813 128 150 Fair value hedge carrying value adjustment 6 6 — — — — — Unamortized debt discount and premium, net (e) 1,712 (17 ) (28 ) (16 ) (8 ) (28 ) (8 ) Unamortized debt issuance costs (f) (164 ) (39 ) (85 ) (37 ) (32 ) (4 ) (19 ) Total debt 4.15 % $ 42,501 $ 8,367 $ 15,772 $ 6,727 $ 5,079 $ 1,701 $ 3,768 Short-term notes payable and commercial paper (3,633 ) — — — — — — Short-term money pool/intercompany borrowings — — (1,308 ) (209 ) (813 ) (103 ) — Current maturities of long-term debt (g) (2,026 ) (356 ) (315 ) (2 ) (13 ) (106 ) (547 ) Total long-term debt (g) $ 36,842 $ 8,011 $ 14,149 $ 6,516 $ 4,253 $ 1,492 $ 3,221 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $114 million and $731 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for commercial paper was 15 days. (e) Duke Energy includes $1,798 million in purchase accounting adjustments related to the merger with Progress Energy. (f) Duke Energy includes $59 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 17 for additional information on amounts from consolidated VIEs. Current Maturities of Long-Term Debt The following table shows the significant components of Current maturities of Long-Term Debt on the Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate December 31, 2016 Unsecured Debt Duke Energy (Parent) April 2017 1.226 % $ 400 Duke Energy (Parent) August 2017 1.625 % 700 Piedmont Natural Gas September 2017 8.510 % 35 First Mortgage Bonds Duke Energy Progress March 2017 1.146 % 250 Duke Energy Florida September 2017 5.800 % 250 Duke Energy Progress November 2017 1.111 % 200 Secured Duke Energy June 2017 2.365 % 45 Duke Energy June 2017 2.260 % 34 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Duke Energy Carolinas February 2017 0.810 % 10 Duke Energy Carolinas February 2017 0.790 % 25 Other (a) 293 Current maturities of long-term debt $ 2,319 (a) Includes capital lease obligations, amortizing debt and small bullet maturities. Maturities and Call Options The following table shows the annual maturities of long-term debt for the next five years and thereafter. Amounts presented exclude short-term notes payable and commercial paper and money pool borrowings for the Subsidiary Registrants. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy (a) Carolinas Energy Progress Florida Ohio Indiana 2017 $ 2,319 $ 116 $ 778 $ 452 $ 326 $ 1 $ 3 2018 3,466 1,629 559 — 561 3 3 2019 3,316 5 1,992 902 292 551 63 2020 2,112 755 469 152 319 25 653 2021 3,699 501 1,473 602 372 49 70 Thereafter 31,090 6,597 12,270 4,903 4,255 1,255 2,994 Total long-term debt, including current maturities $ 46,002 $ 9,603 $ 17,541 $ 7,011 $ 6,125 $ 1,884 $ 3,786 (a) Excludes $1,893 million in purchase accounting adjustments related to the Progress Energy merger and the Piedmont acquisition. The Duke Energy Registrants have the ability under certain debt facilities to call and repay the obligation prior to its scheduled maturity. Therefore, the actual timing of future cash repayments could be materially different than as presented above. Short-Term Obligations Classified as Long-Term Debt Tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder and certain commercial paper issuances and money pool borrowings are classified as Long-Term Debt on the Consolidated Balance Sheets. These tax-exempt bonds, commercial paper issuances and money pool borrowings, which are short-term obligations by nature, are classified as long term due to Duke Energy’s intent and ability to utilize such borrowings as long-term financing. As Duke Energy’s Master Credit Facility and other bilateral letter of credit agreements have non-cancelable terms in excess of one year as of the balance sheet date, Duke Energy has the ability to refinance these short-term obligations on a long-term basis. The following tables show short-term obligations classified as long-term debt. December 31, 2016 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 347 $ 35 $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 972 $ 335 $ 150 $ 52 $ 435 December 31, 2015 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 347 $ 35 $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 972 $ 335 $ 150 $ 52 $ 435 (a) Progress Energy amounts are equal to Duke Energy Progress amounts. Summary of Significant Debt Issuances Piedmont Acquisition Financing In August 2016, Duke Energy issued $3.75 billion of senior unsecured notes in three separate series. The net proceeds were used to finance a portion of the Piedmont acquisition. The $4.9 billion Bridge Facility was terminated following the issuance of this debt. See Note 2 for additional information on the Piedmont acquisition. Nuclear Asset-Recovery Bonds In June 2016, DEFPF issued $1,294 million of nuclear asset-recovery bonds and used the proceeds to acquire nuclear asset-recovery property from its parent, Duke Energy Florida. The nuclear asset-recovery bonds are payable only from and secured by the nuclear asset-recovery property. DEFPF is consolidated for financial reporting purposes; however, the nuclear asset-recovery bonds do not constitute a debt, liability or other legal obligation of, or interest in, Duke Energy Florida or any of its affiliates other than DEFPF. The assets of DEFPF, including the nuclear asset-recovery property, are not available to pay creditors of Duke Energy Florida or any of its affiliates. Duke Energy Florida used the proceeds from the sale to repay short-term borrowings under the intercompany money pool borrowing arrangement and make an equity distribution of $649 million to the ultimate parent, Duke Energy (Parent), which repaid short-term borrowings. See Notes 4 and 17 for additional information. Solar Facilities Financing In August 2016, Emerald State Solar, LLC, an indirect wholly owned subsidiary of Duke Energy, entered into a $333 million portfolio financing of approximately 22 North Carolina Solar facilities. Tranche A of $228 million is secured by substantially all the assets of the solar facilities and is nonrecourse to Duke Energy. Tranche B of $105 million is secured by an Equity Contribution Agreement with Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures related to the Emerald State Solar, LLC portfolio. The initial interest rate on the loans was six months London Interbank Offered Rate (LIBOR) plus an applicable margin of 1.75 percent plus a 0.125 percent increase every three years thereafter. In connection with this debt issuance, Emerald State Solar, LLC entered into two interest rate swaps to convert the substantial majority of the loan interest payments from variable rates to fixed rates of approximately 1.81 percent for Tranche A and 1.38 percent for Tranche B, plus the applicable margin. See Note 14 for further information on the notional amounts of the interest rate swaps. Duke Energy Florida Bond Issuance In January 2017, Duke Energy Florida issued $900 million of first mortgage bonds. The issuance was split between a $250 million , three-year series and a $650 million , 10-year series. The net proceeds from the issuance were used to repay at maturity $250 million aggregate principal amount of bonds due September 2017, as well as to fund capital expenditures for ongoing construction and capital maintenance and for general corporate purposes. The following tables summarize significant debt issuances (in millions). Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Unsecured Debt April 2016 (a) April 2023 2.875 % $ 350 $ 350 $ — $ — $ — $ — $ — August 2016 September 2021 1.800 % 750 750 — — — — — August 2016 September 2026 2.650 % 1,500 1,500 — — — — — August 2016 September 2046 3.750 % 1,500 1,500 — — — — — Secured Debt June 2016 (b) March 2020 1.196 % 183 — — — 183 — — June 2016 (b) September 2022 1.731 % 150 — — — 150 — — June 2016 (b) September 2029 2.538 % 436 — — — 436 — — June 2016 (b) March 2033 2.858 % 250 — — — 250 — — June 2016 (b) September 2036 3.112 % 275 — — — 275 — — August 2016 June 2034 2.747 % 228 — — — — — — August 2016 June 2020 2.747 % 105 — — — — — — First Mortgage Bonds March 2016 (c) March 2023 2.500 % 500 — 500 — — — — March 2016 (c) March 2046 3.875 % 500 — 500 — — — — May 2016 (d) May 2046 3.750 % 500 — — — — — 500 June 2016 (c) June 2046 3.700 % 250 — — — — 250 — September 2016 (e) October 2046 3.400 % 600 — — — 600 — — September 2016 (c) October 2046 3.700 % 450 — — 450 — — — November 2016 (f) December 2026 2.950 % 600 — 600 — — — — Total issuances $ 9,127 $ 4,100 $ 1,600 $ 450 $ 1,894 $ 250 $ 500 (a) Proceeds were used to pay down outstanding commercial paper and for general corporate purposes. (b) The nuclear asset recovery bonds are sequential pay amortizing bonds. The maturity date above represents the scheduled final maturity date for the bonds. (c) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. (d) Proceeds were used to repay $325 million of unsecured debt due June 2016, $150 million of first mortgage bonds due July 2016 and for general corporate purposes. (e) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance, to repay short-term borrowings under the intercompany money pool borrowing arrangement and for general corporate purposes. (f) Proceeds were used to repay at maturity $350 million aggregate principal amount of certain bonds due December 2016, as well as to fund capital expenditures for ongoing construction and capital maintenance and for general corporate purposes. Year Ended December 31, 2015 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Unsecured Debt November 2015 (a)(b) April 2024 3.750 % $ 400 $ 400 $ — $ — November 2015 (a)(b) December 2045 4.800 % 600 600 — — First Mortgage Bonds March 2015 (c) June 2045 3.750 % 500 — 500 — August 2015 (a)(d) August 2025 3.250 % 500 — — 500 August 2015 (a)(d) August 2045 4.200 % 700 — — 700 Total issuances $ 2,700 $ 1,000 $ 500 $ 1,200 (a) Proceeds were used to repay short-term money pool and commercial paper borrowing issued to fund a portion of the NCEMPA acquisition, see Note 2 for further information. (b) Proceeds were used to refinance at maturity $300 million of unsecured notes at Progress Energy due January 2016. (c) Proceeds were used to redeem at maturity $500 million of first mortgage bonds due October 2015. (d) Proceeds were used to refinance at maturity $400 million of first mortgage bonds due December 2015. Available Credit Facilities Duke Energy has a Master Credit Facility with a capacity of $7.5 billion through January 2020. The Duke Energy Registrants, excluding Progress Energy (Parent) and Piedmont, have borrowing capacity under the Master Credit Facility up to specified sublimits for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower. The amount available under the Master Credit Facility has been reduced to backstop issuances of commercial paper, certain letters of credit and variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder. Duke Energy Carolinas and Duke Energy Progress are also required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet obligations under plea agreements reached with the U.S. Department of Justice in 2015 related to violations at North Carolina facilities with ash basins. Piedmont has a separate five-year revolving syndicated credit facility, with a capacity of $850 million through December 2020 and an expansion option of up to an additional $200 million . The facility provides a line of credit for letters of credit of $10 million . The table below includes the current borrowing sublimits and available capacity under these credit facilities. December 31, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (a) (Parent) Carolinas Progress Florida Ohio Indiana Facility size (b) $ 8,350 $ 3,400 $ 1,100 $ 1,000 $ 950 $ 450 $ 600 Reduction to backstop issuances Commercial paper (c) (2,022 ) (977 ) (300 ) (150 ) (84 ) (31 ) (150 ) Outstanding letters of credit (78 ) (69 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 5,634 $ 2,354 $ 511 $ 598 $ 865 $ 419 $ 369 (a) Includes amounts related to Piedmont's $850 million credit facility. (b) Represents the sublimit of each borrower. (c) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Consolidated Balance Sheets. Term Loan Facility In 2016, Duke Energy (Parent) entered into a $1.5 billion term loan facility, as amended (Term Loan) maturing on July 31, 2017. During 2016, Duke Energy (Parent) drew the full amount available under the Term Loan and used $750 million of proceeds to fund a portion of the Piedmont acquisition and the remaining $750 million to manage short-term liquidity and for general corporate purposes. The terms and conditions of the Term Loan are generally consistent with those governing Duke Energy’s Master Credit Facility. In December 2016, Duke Energy (Parent) repaid the $1.5 billion term loan which terminated this credit facility. Other Debt Matters In September 2016, Duke Energy filed a Registration statement (Form S-3) with the SEC. Under this Form S-3, which is uncapped, the Duke Energy Registrants, excluding Progress Energy, may issue debt and other securities in the future at amounts, prices and with terms to be determined at the time of future offerings. The registration statement was filed to replace a similar prior filing upon expiration of its three-year term and also allows for the issuance of common stock by Duke Energy. Duke Energy has an effective Form S-3 with the SEC to sell up to $3 billion of variable denomination floating-rate demand notes, called PremierNotes. The Form S-3 states that no more than $1.5 billion of the notes will be outstanding at any particular time. The notes are offered on a continuous basis and bear interest at a floating rate per annum determined by the Duke Energy PremierNotes Committee, or its designee, on a weekly basis. The interest rate payable on notes held by an investor may vary based on the principal amount of the investment. The notes have no stated maturity date, are non-transferable and may be redeemed in whole or in part by Duke Energy or at the investor’s option at any time. The balance as of December 31, 2016 and 2015 was $1,090 million and $1,121 million , respectively. The notes are short-term debt obligations of Duke Energy and are reflected as Notes payable and commercial paper on Duke Energy’s Consolidated Balance Sheets. In January 2017, Duke Energy amended its Form S-3 to add Piedmont as a registrant and included in the amendment a prospectus for Piedmont under which it may issue debt securities in the same manner as other Duke Energy Registrants. Duke Energy guaranteed debt issued by Duke Energy Carolinas of $762 million and $767 million , respectively, as of December 31, 2016 and 2015 . Money Pool The Subsidiary Registrants, excluding Progress Energy, are eligible to receive support for their short-term borrowing needs through participation with Duke Energy and certain of its subsidiaries in a money pool arrangement. Under this arrangement, those companies with short-term funds may provide short-term loans to affiliates participating in this arrangement. The money pool is structured such that the Subsidiary Registrants, excluding Progress Energy, separately manage their cash needs and working capital requirements. Accordingly, there is no net settlement of receivables and payables between money pool participants. Duke Energy (Parent), may loan funds to its participating subsidiaries, but may not borrow funds through the money pool. Accordingly, as the money pool activity is between Duke Energy and its wholly owned subsidiaries, all money pool balances are eliminated within Duke Energy’s Consolidated Balance Sheets. Money pool receivable balances are reflected within Notes receivable from affiliated companies on the Subsidiary Registrants’ Consolidated Balance Sheets. Money pool payable balances are reflected within either Notes payable to affiliated companies or Long-Term Debt Payable to Affiliated Companies on the Subsidiary Registrants’ Consolidated Balance Sheets. Restrictive Debt Covenants The Duke Energy Registrants’ debt and credit agreements contain various financial and other covenants. Duke Energy's Master Credit Facility contains a covenant requiring the debt-to-total capitalization ratio not to exceed 65 percent for each borrower. Piedmont's credit facility contains a debt-to-total capitalization ratio covenant not to exceed 70 percent . Failure to meet those covenants beyond applicable grace periods could result in accelerated due dates and/or termination of the agreements. As of December 31, 2016 , each of the Duke Energy Registrants were in compliance with all covenants related to their debt agreements. In addition, some credit agreements may allow for acceleration of payments or termination of the agreements due to nonpayment, or acceleration of other significant indebtedness of the borrower or some of its subsidiaries. None of the debt or credit agreements contain material adverse change clauses. Other Loans As of December 31, 2016 and 2015 , Duke Energy had loans outstanding of $661 million , including $39 million at Duke Energy Progress and $629 million , including $41 million at Duke Energy Progress, respectively, against the cash surrender value of life insurance policies it owns on the lives of its executives. The amounts outstanding were carried as a reduction of the related cash surrender value that is included in Other within Investments and Other Assets on the Consolidated Balance Sheets.

Guarantees and Indemnifications

Guarantees and Indemnifications	12 Months Ended
	Dec. 31, 2016
Guarantees [Abstract]
Guarantees and Indemnifications	GUARANTEES AND INDEMNIFICATIONS Duke Energy and Progress Energy have various financial and performance guarantees and indemnifications, which are issued in the normal course of business. As discussed below, these contracts include performance guarantees, stand-by letters of credit, debt guarantees, surety bonds and indemnifications. Duke Energy and Progress Energy enter into these arrangements to facilitate commercial transactions with third parties by enhancing the value of the transaction to the third party. At December 31, 2016 , Duke Energy and Progress Energy do not believe conditions are likely for significant performance under these guarantees. To the extent liabilities are incurred as a result of the activities covered by the guarantees, such liabilities are included on the accompanying Consolidated Balance Sheets. On January 2, 2007, Duke Energy completed the spin-off of its natural gas businesses to shareholders. Guarantees issued by Duke Energy or its affiliates, or assigned to Duke Energy prior to the spin-off, remained with Duke Energy subsequent to the spin-off. Guarantees issued by Spectra Energy Capital, LLC (Spectra Capital) or its affiliates prior to the spin-off remained with Spectra Capital subsequent to the spin-off, except for guarantees that were later assigned to Duke Energy. Duke Energy has indemnified Spectra Capital against any losses incurred under certain of the guarantee obligations that remain with Spectra Capital. At December 31, 2016 , the maximum potential amount of future payments associated with these guarantees was $205 million , the majority of which expires by 2028. Duke Energy has issued performance guarantees to customers and other third parties that guarantee the payment and performance of other parties, including certain non-wholly owned entities, as well as guarantees of debt of certain non-consolidated entities and less than wholly owned consolidated entities. If such entities were to default on payments or performance, Duke Energy would be required under the guarantees to make payments on the obligations of the less than wholly owned entity. The maximum potential amount of future payments required under these guarantees as of December 31, 2016 , was $333 million . Of this amount, $11 million relates to guarantees issued on behalf of less than wholly owned consolidated entities, with the remainder related to guarantees issued on behalf of third parties and unconsolidated affiliates of Duke Energy. Of the guarantees noted above, $215 million of the guarantees expire between 2017 and 2033, with the remaining performance guarantees having no contractual expiration. Duke Energy has guaranteed certain issuers of surety bonds, obligating itself to make payment upon the failure of a wholly owned and former non-wholly owned entity to honor its obligations to a third party. Under these arrangements, Duke Energy has payment obligations that are triggered by a draw by the third party or customer due to the failure of the wholly owned or former non-wholly owned entity to perform according to the terms of its underlying contract. At December 31, 2016 , Duke Energy had guaranteed $44 million of outstanding surety bonds, most of which have no set expiration. Duke Energy uses bank-issued stand-by letters of credit to secure the performance of wholly owned and non-wholly owned entities to a third party or customer. Under these arrangements, Duke Energy has payment obligations to the issuing bank which are triggered by a draw by the third party or customer due to the failure of the wholly owned or non-wholly owned entity to perform according to the terms of its underlying contract. At December 31, 2016 , Duke Energy had issued a total of $485 million in letters of credit, which expire between 2017 and 2020. The unused amount under these letters of credit was $77 million . Duke Energy and Progress Energy have issued indemnifications for certain asset performance, legal, tax and environmental matters to third parties, including indemnifications made in connection with sales of businesses. At December 31, 2016 , the estimated maximum exposure for these indemnifications was $96 million , the majority of which expires in 2017. Of this amount, $7 million has no contractual expiration. For certain matters for which Progress Energy receives timely notice, indemnity obligations may extend beyond the notice period. Certain indemnifications related to discontinued operations have no limitations as to time or maximum potential future payments. The following table includes the liabilities recognized for the guarantees discussed above. These amounts are primarily recorded in Other within Deferred Credits and other Liabilities on the Consolidated Balance Sheets. As current estimates change, additional losses related to guarantees and indemnifications to third parties, which could be material, may be recorded by the Duke Energy Registrants in the future. December 31, (in millions) 2016 2015 Duke Energy $ 13 $ 21 Progress Energy — 7 Duke Energy Florida — 7

Joint Ownership of Generating a

Joint Ownership of Generating and Transmission Facilities	12 Months Ended
	Dec. 31, 2016
Joint Ownership Of Generating And Transmission Facilities [Abstract]
Joint Ownership of Generating and Transmission Facilities	JOINT OWNERSHIP OF GENERATING AND TRANSMISSION FACILITIES The Duke Energy Registrants maintain ownership interests in certain jointly owned generating and transmission facilities. The Duke Energy Registrants are entitled to a share of the generating capacity and output of each unit equal to their respective ownership interests. The Duke Energy Registrants pay their ownership share of additional construction costs, fuel inventory purchases and operating expenses. The Duke Energy Registrants share of revenues and operating costs of the jointly owned facilities is included within the corresponding line in the Consolidated Statements of Operations. Each participant in the jointly owned facilities must provide its own financing. The following table presents the Duke Energy Registrants' interest of jointly owned plant or facilities and amounts included on the Consolidated Balance Sheets. All facilities are operated by the Duke Energy Registrants and are included in the Electric Utilities and Infrastructure segment. December 31, 2016 Construction Ownership Property, Plant Accumulated Work in (in millions except for ownership interest) Interest and Equipment Depreciation Progress Duke Energy Carolinas Catawba Nuclear Station (units 1 and 2) (a) 19.25 % $ 954 $ 612 $ 12 Duke Energy Ohio Transmission facilities (b) Various 90 60 1 Duke Energy Indiana Gibson Station (unit 5) (c) 50.05 % 333 157 11 Vermillion Generating Station (d) 62.5 % 154 111 — Transmission and local facilities (c) Various 4,315 1,715 — (a) Jointly owned with North Carolina Municipal Power Agency Number 1, NCEMC and Piedmont Municipal Power Agency. (b) Jointly owned with America Electric Power Generation Resources and The Dayton Power and Light Company. (c) Jointly owned with Wabash Valley Power Association, Inc. (WVPA) and Indiana Municipal Power Agency. (d) Jointly owned with WVPA. On August 31, 2016, Duke Energy Florida completed the purchase of Georgia Power Company's (GPC) ownership interest in Intercession City Station Unit 11 for an amount equal to GPC's net book value of the facility as of the transaction close date. Following the purchase, Duke Energy Florida controls the entire output of the facility. At December 31, 2016, Duke Energy Florida owns 100 percent of the retired Crystal River Unit 3. Duke Energy Florida completed the purchase of 1.7 percent ownership interest from Seminole Electric Cooperative, Inc. on November 30, 2016. On October 30, 2015, Duke Energy Florida completed the purchase of 6.52 percent ownership interest from the Florida Municipal Joint Owners and settled other disputes for $55 million . All costs associated with Crystal River Unit 3 are included within Regulatory assets on the Consolidated Balance Sheets of Duke Energy, Progress Energy and Duke Energy Florida. See Note 4 for additional information.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2016
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS Duke Energy records an ARO when it has a legal obligation to incur retirement costs associated with the retirement of a long-lived asset and the obligation can be reasonably estimated. Certain assets of the Duke Energy Registrants’ have an indeterminate life, such as transmission and distribution facilities, and thus the fair value of the retirement obligation is not reasonably estimable. A liability for these AROs will be recorded when a fair value is determinable. The Duke Energy Registrants’ regulated operations accrue costs of removal for property that does not have an associated legal retirement obligation based on regulatory orders from state commissions. These costs of removal are recorded as a regulatory liability in accordance with regulatory accounting treatment. The Duke Energy Registrants do not accrue the estimated cost of removal for any nonregulated assets. See Note 4 for the estimated cost of removal for assets without an associated legal retirement obligation, which are included in Regulatory liabilities on the Consolidated Balance Sheets. The following table presents the AROs recorded on the Consolidated Balance Sheets. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Decommissioning of Nuclear Power Facilities (a) $ 5,204 $ 1,834 $ 3,172 $ 2,454 $ 717 $ — $ — Closure of Ash Impoundments 5,150 2,032 2,228 2,209 19 43 847 Other (b) 257 29 75 34 42 34 19 Total asset retirement obligation $ 10,611 $ 3,895 $ 5,475 $ 4,697 $ 778 $ 77 $ 866 Less: current portion 411 222 189 189 — — — Total noncurrent asset retirement obligation $ 10,200 $ 3,673 $ 5,286 $ 4,508 $ 778 $ 77 $ 866 (a) The Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy. (b) Primarily includes obligations related to asbestos removal and the closure of certain landfills at fossil generation facilities. Duke Energy Ohio also includes AROs related to the retirement of natural gas mains and services. Duke Energy includes AROs related to the removal of renewable energy generation assets and Piedmont's underground natural gas mains and services. North Carolina Ash Basins AROs recorded on the Duke Energy Carolinas and Duke Energy Progress Consolidated Balance Sheets include the legal obligation for closure of coal ash basins and the disposal of related ash as a result of the Coal Ash Act, the EPA CCR rule and other agreements. In 2014 the Coal Ash Act became law and was amended on June 24, 2015, and July 14, 2016. The Coal Ash Act, as amended, • Prohibits construction of new and expansion of existing ash impoundments and use of existing impoundments at retired facilities; • Requires ash impoundments in North Carolina to be categorized as high risk, intermediate risk or low risk by the NCDEQ with the method of closure and timing to be based upon the assigned risk, with closure no later than December 31, 2029 (see below for category descriptions); • Classifies Duke Energy Progress' Asheville and Sutton plants and Duke Energy Carolinas' Riverbend and Dan River stations as high risk; • Requires dry disposal of fly ash at active plants, excluding the Asheville Plant, not retired by December 31, 2018; • Requires dry disposal of bottom ash at active plants, excluding the Asheville Plant, by December 31, 2019, or retirement of active plants; • Establishes requirements to deal with groundwater and surface water impacts from impoundments; and • Increases the level of regulation for structural fills utilizing coal ash. High risk basins (Asheville, Sutton, Riverbend and Dan River) require closure through excavation, including a combination of transferring the ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of high risk basins is required to be completed no later than August 1, 2019, except for Asheville which is required to be completed no later than August 1, 2022. Intermediate risk basins require closure through excavation including a combination of converting the basin to a lined industrial landfill, transferring of the ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of intermediate risk basins is required to be completed no later than December 31, 2024, except for H.F. Lee, Cape Fear and Weatherspoon to be completed no later than August 1, 2028. Low risk basins require closure through either the combination of the installation and maintenance of a cap system and groundwater monitoring system designed to minimize infiltration and erosion or other closure options available to intermediate risk basins. Closure of low risk basins is required to be completed no later than December 31, 2029. In January 2016, the NCDEQ published draft risk classifications for sites not specifically delineated by the Coal Ash Act as high risk. These risk rankings were generally determined based on three primary criteria: structural integrity of the impoundments and impacts to surface water and to groundwater. The NCDEQ's draft proposed classifications categorized 12 basins at four sites as intermediate risk and four basins at three sites as low risk. The NCDEQ's draft proposed classifications also categorized nine basins at six sites as “low-to-intermediate” risk, thereby not assigning a definitive risk ranking at that time. On May 18, 2016, the NCDEQ issued new proposed risk classifications, proposing to rank all originally proposed low risk and "low-to-intermediate" risk sites as intermediate. On July 14, 2016, the former governor of North Carolina signed legislation which amended the Coal Ash Act and required Duke Energy to undertake dam improvement projects and to provide access to a permanent alternative drinking water source to certain residents within a half mile of coal ash basin compliance boundaries and to certain other potentially impacted residents. The new legislation also ranks basins at the H.F. Lee, Cape Fear and Weatherspoon stations as intermediate risk consistent with Duke Energy's previously announced plans to excavate those basins. These specific intermediate basins require closure through excavation including a combination of transferring ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of these specific intermediate basins is required to be completed no later than August 1, 2028. Upon satisfactory completion of the dam improvement projects and installation of alternative drinking water sources by October 15, 2018, the legislation requires the NCDEQ to reclassify sites proposed as intermediate risk, excluding H.F. Lee, Cape Fear and Weatherspoon, as low risk. In January 2017, NCDEQ issued preliminary approval of Duke Energy's plans for the alternative water sources. Per the Coal Ash Act, final proposed classifications were to be subject to Coal Ash Management Commission (Coal Ash Commission) approval. In March 2016, the Coal Ash Commission created by the Coal Ash Act was disbanded by the former governor of North Carolina based on a North Carolina Supreme Court ruling regarding the constitutionality of the body. The July 2016 legislation eliminates the Coal Ash Commission and transfers responsibility for ash basin closure oversight to the NCDEQ. Additionally, the July 2016 legislation requires the installation and operation of three large-scale coal ash beneficiation projects which are expected to produce reprocessed ash for use in the concrete industry. Closure of basins at sites with these beneficiation projects are required to be completed no later than December 31, 2029. On October 5, 2016, Duke Energy announced Buck Steam Station as a first location for one of the beneficiation projects. On December 13, 2016, Duke Energy announced H.F. Lee as the second location. Duke Energy intends to announce the third location by July 1, 2017. The Coal Ash Act includes a variance procedure for compliance deadlines and other issues surrounding the management of CCR and CCR surface impoundments. Provisions of the Coal Ash Act prohibit cost recovery in customer rates for unlawful discharge of ash impoundment waters occurring after January 1, 2014. The Coal Ash Act leaves the decision on cost recovery determinations related to closure of ash impoundments to the normal ratemaking processes before utility regulatory commissions. Consistent with the requirements of the Coal Ash Act, Duke Energy has submitted CSAs and groundwater corrective action plans to NCDEQ and will submit to NCDEQ site-specific coal ash impoundment closure plans in advance of closure. These plans and all associated permits must be approved by NCDEQ before any closure work can begin. Federal Coal Combustion Residuals Regulation In April 2015, the EPA published a rule to regulate the disposal of CCR from electric utilities as solid waste. The federal regulation classifies CCR as nonhazardous waste and allows for beneficial use of CCR with some restrictions. The regulation applies to all new and existing landfills, new and existing surface impoundments receiving CCR and existing surface impoundments that are no longer receiving CCR but contain liquid located at stations currently generating electricity (regardless of fuel source). The rule establishes requirements regarding landfill design, structural integrity design and assessment criteria for surface impoundments, groundwater monitoring and protection procedures and other operational and reporting procedures to ensure the safe disposal and management of CCR. As a result of the EPA rule, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana recorded additional ARO amounts during 2015. In addition to the requirements of the federal CCR regulation, CCR landfills and surface impoundments will continue to be independently regulated by most states. In September 2014, Duke Energy Carolinas executed a consent agreement with the South Carolina Department of Health and Environmental Control (SCDHEC) requiring the excavation of an inactive ash basin and ash fill area at the W.S. Lee Steam Station. As part of this agreement, in December 2014, Duke Energy Carolinas filed an ash removal plan and schedule with SCDHEC. In April 2015, the federal CCR rules were published and Duke Energy Carolinas subsequently executed an agreement with the conservation groups Upstate Forever and Save Our Saluda that requires Duke Energy Carolinas to remediate all active and inactive ash storage areas at the W.S. Lee Steam Station. Coal-fired generation at W.S. Lee ceased in 2014 and unit 3 was converted to natural gas in March 2015. In July 2015, Duke Energy Progress executed a consent agreement with the SCDHEC requiring the excavation of an inactive ash fill area at the Robinson Plant within eight years. Coal ash impoundments at the Robinson Plant and W.S. Lee Station sites are required to be closed pursuant to the CCR rule and the provisions of these consent agreements are consistent with the federal CCR closure requirements. Coal Ash Liability The ARO amount recorded on the Consolidated Balance Sheets is based upon estimated closure costs for impacted ash impoundments. The amount recorded represents the discounted cash flows for estimated closure costs based upon either specific closure plans or the probability weightings of the potential closure methods as evaluated on a site-by-site basis. Actual costs to be incurred will be dependent upon factors that vary from site to site. The most significant factors are the method and time frame of closure at the individual sites. Closure methods considered include removing the water from the basins, consolidating material as necessary and capping the ash with a synthetic barrier, excavating and relocating the ash to a lined structural fill or lined landfill, or recycling the ash for concrete or some other beneficial use. The ultimate method and timetable for closure will be in compliance with standards set by federal and state regulations. The ARO amount will be adjusted as additional information is gained through the closure and post-closure process, including acceptance and approval of compliance approaches which may change management assumptions, and may result in a material change to the balance. See ARO Liability Rollforward section below for information about revisions made to the coal ash liability during 2016. Asset retirement costs associated with the AROs for operating plants and retired plants are included in Net property, plant and equipment and Regulatory assets, respectively, on the Consolidated Balance Sheets. See Note 4 for additional information on Regulatory assets related to AROs. Cost recovery for future expenditures will be pursued through the normal ratemaking process with federal and state utility commissions, which permit recovery of necessary and prudently incurred costs associated with Duke Energy’s regulated operations. Nuclear Decommissioning Liability AROs related to nuclear decommissioning are based on site-specific cost studies. The NCUC, PSCSC and FPSC require updated cost estimates for decommissioning nuclear plants every five years. The following table summarizes information about the most recent site-specific nuclear decommissioning cost studies. Decommissioning costs in the table below are presented in dollars of the year of the cost study and include costs to decommission plant components not subject to radioactive contamination. Annual Funding Decommissioning (in millions) Requirement (a) Costs (a)(b) Year of Cost Study Duke Energy $ 14 $ 8,150 2013 and 2014 Duke Energy Carolinas — 3,420 2013 Duke Energy Progress 14 3,550 2014 Duke Energy Florida — 1,180 2013 (a) Amounts for Progress Energy equal the sum of Duke Energy Progress and Duke Energy Florida. (b) Amounts include the Subsidiary Registrant's ownership interest in jointly owned reactors. Other joint owners are responsible for decommissioning costs related to their interest in the reactors. Nuclear Decommissioning Trust Funds Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida each maintain NDTFs that are intended to pay for the decommissioning costs of the respective nuclear power plants. The NDTF investments are managed and invested in accordance with applicable requirements of various regulatory bodies including the NRC, FERC, NCUC, PSCSC, FPSC and the Internal Revenue Service (IRS). Use of the NDTF investments is restricted to nuclear decommissioning activities including license termination, spent fuel and site restoration. The license termination and spent fuel obligations relate to contaminated decommissioning and are recorded as AROs. The site restoration obligation relates to non-contaminated decommissioning and is recorded to cost of removal within Regulatory liabilities on the Consolidated Balance Sheets. The following table presents the fair value of NDTF assets legally restricted for purposes of settling AROs associated with nuclear decommissioning. Duke Energy Florida is actively decommissioning Crystal River Unit 3 and was granted an exemption from the NRC which allows for use of the NDTF for all aspects of nuclear decommissioning. Therefore, the entire balance of Duke Energy Florida's NDTF may be applied toward license termination, spent fuel and site restoration costs incurred to decommission Crystal River Unit 3. December 31, (in millions) 2016 2015 Duke Energy $ 5,099 $ 4,670 Duke Energy Carolinas 2,882 2,686 Duke Energy Progress 2,217 1,984 See Note 16 for additional information related to the fair value of the Duke Energy Registrants' NDTFs. Nuclear Operating Licenses Operating licenses for nuclear units are potentially subject to extension. The following table includes the current expiration of nuclear operating licenses. Unit Year of Expiration Duke Energy Carolinas Catawba Units 1 and 2 2043 McGuire Unit 1 2041 McGuire Unit 2 2043 Oconee Units 1 and 2 2033 Oconee Unit 3 2034 Duke Energy Progress Brunswick Unit 1 2036 Brunswick Unit 2 2034 Harris 2046 Robinson 2030 Duke Energy Florida has requested the NRC terminate the operating license for Crystal River Unit 3 as it permanently ceased operation in February 2013. Refer to Note 4 for further information on the Crystal River Unit 3 decommissioning activity and transition to SAFSTOR. ARO Liability Rollforward During 2016, the Duke Energy Registrants updated coal ash ARO liability estimates based on additional site-specific information about the related costs, methods and timing of work to be performed. Actual closure costs incurred could be materially different from current estimates that form the basis of the recorded AROs. The following table presents changes in the liability associated with AROs. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2014 $ 8,464 $ 3,428 $ 4,711 $ 3,905 $ 806 $ 27 $ 32 Acquisitions (a) 226 — 226 204 23 — — Accretion expense (b) 380 165 203 169 34 4 15 Liabilities settled (c) (422 ) (200 ) (195 ) (125 ) (70 ) (4 ) (23 ) Liabilities incurred in the current year (d) 1,016 178 282 282 — 116 418 Revisions in estimates of cash flows 585 347 142 132 9 (18 ) 83 Balance at December 31, 2015 10,249 3,918 5,369 4,567 802 125 525 Acquisitions 22 — 2 — 2 — — Accretion expense (b) 400 187 230 194 35 5 24 Liabilities settled (c) (613 ) (287 ) (272 ) (212 ) (60 ) (5 ) (49 ) Liabilities incurred in the current year 51 — 3 3 — — 29 Revisions in estimates of cash flows 502 77 143 145 (1 ) (48 ) 337 Balance at December 31, 2016 $ 10,611 $ 3,895 $ 5,475 $ 4,697 $ 778 $ 77 $ 866 (a) Duke Energy Progress amount relates to the NCEMPA acquisition. See Note 2 for additional information. (b) Substantially all accretion expense for the years ended December 31, 2016 and 2015 relates to Duke Energy’s regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (c) Amounts primarily relate to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3. (d) Amounts primarily relate to AROs recorded as a result of the EPA's rule for disposal of CCR.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2016 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,501 $ 432 $ 735 $ 393 $ 342 $ 150 $ 106 Plant – Regulated Electric generation, distribution and transmission 8 - 100 89,864 34,515 37,596 23,683 13,913 4,593 13,160 Natural gas transmission and distribution 12 - 67 7,738 — — — — 2,456 — Other buildings and improvements 15 - 100 1,692 502 634 293 341 211 197 Plant – Nonregulated Electric generation, distribution and transmission 5 - 30 4,298 — — — — — — Other buildings and improvements 25 - 35 421 — — — — — — Nuclear fuel 3,572 2,092 1,480 1,480 — — — Equipment 3 - 38 1,941 358 505 378 127 338 156 Construction in process 6,186 2,324 2,708 1,329 1,379 206 396 Other 5 - 40 4,184 904 1,206 863 332 172 226 Total property, plant and equipment (a)(d) 121,397 41,127 44,864 28,419 16,434 8,126 14,241 Total accumulated depreciation – regulated (b)(c)(d) (37,831 ) (14,365 ) (15,212 ) (10,561 ) (4,644 ) (2,579 ) (4,317 ) Total accumulated depreciation – nonregulated (c)(d) (1,575 ) — — — — — — Generation facilities to be retired, net 529 — 529 529 — — — Total net property, plant and equipment $ 82,520 $ 26,762 $ 30,181 $ 18,387 $ 11,790 $ 5,547 $ 9,924 (a) Includes capitalized leases of $1,355 million , $40 million , $288 million , $142 million , $146 million , $81 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $99 million , $9 million and $90 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,922 million , $1,192 million , $730 million and $730 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $50 million , $9 million , $19 million and $8 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,591 million and accumulated depreciation of consolidated VIEs of $411 million at Duke Energy. December 31, 2015 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,391 $ 407 $ 719 $ 392 $ 327 $ 118 $ 108 Plant – Regulated Electric generation, distribution and transmission 8 - 100 87,593 33,623 36,422 22,888 13,534 4,429 13,118 Natural gas transmission and distribution 12 - 67 2,322 — — — — 2,322 — Other buildings and improvements 15 - 100 1,480 477 621 294 322 204 179 Plant – Nonregulated Electric generation, distribution and transmission 1 - 30 3,348 — — — — — — Other buildings and improvements 25 - 35 410 — — — — — — Nuclear fuel 3,194 1,827 1,367 1,367 — — — Equipment 3 - 38 1,736 368 530 398 132 344 173 Construction in process 4,485 1,860 1,827 1,118 709 180 214 Other 5 - 60 4,008 836 1,180 856 319 153 215 Total property, plant and equipment (a)(d) 109,967 39,398 42,666 27,313 15,343 7,750 14,007 Total accumulated depreciation – regulated (b)(c)(d) (35,367 ) (13,521 ) (14,867 ) (10,141 ) (4,720 ) (2,507 ) (4,484 ) Total accumulated depreciation – nonregulated (c)(d) (1,369 ) — — — — — — Generation facilities to be retired, net 548 — 548 548 — — — Total net property, plant and equipment $ 73,779 $ 25,877 $ 28,347 $ 17,720 $ 10,623 $ 5,243 $ 9,523 (a) Includes capitalized leases of $1,465 million , $40 million , $302 million , $144 million , $158 million , $96 million and $39 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily in regulated plant. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $85 million , $7 million and $78 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,621 million , $976 million , $645 million and $645 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $57 million , $11 million , $27 million and $7 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,033 million and accumulated depreciation of consolidated VIEs of $327 million at Duke Energy. The following table presents capitalized interest, which includes the debt component of AFUDC. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 100 $ 98 $ 75 Duke Energy Carolinas 38 38 38 Progress Energy 31 24 11 Duke Energy Progress 17 20 10 Duke Energy Florida 14 4 1 Duke Energy Ohio 8 10 10 Duke Energy Indiana 7 6 6 Operating Leases Duke Energy's Commercial Renewables segment operates various renewable energy projects and sells the generated output to utilities, electric cooperatives, municipalities and commercial and industrial customers through long-term contracts. In certain situations, these long-term contracts and the associated renewable energy projects qualify as operating leases. Rental income from these leases is accounted for as Operating Revenues in the Consolidated Statements of Operations. There are no minimum lease payments as all payments are contingent based on actual electricity generated by the renewable energy projects. Contingent lease payments were $216 million , $172 million and $164 million for the years ended December 31, 2016, 2015 and 2014. As of December 31, 2016, renewable energy projects owned by Duke Energy and accounted for as operating leases had a cost basis of $3,127 million and accumulated depreciation of $347 million . These assets are principally classified as nonregulated electric generation and transmission assets.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS Goodwill The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill at December 31, 2015 $ 15,656 $ 294 $ 122 $ 16,072 Piedmont Acquisition (a) 1,723 1,630 — 3,353 Goodwill at December 31, 2016 $ 17,379 $ 1,924 $ 122 $ 19,425 (a) Refer to Note 2 for more information on the purchase accounting related to the acquisition of Piedmont. Duke Energy Ohio Duke Energy Ohio's Goodwill balance of $920 million , allocated $596 million to Electric Utilities and Infrastructure and $324 million to Gas Utilities and Infrastructure, is presented net of accumulated impairment charges of $216 million on the Consolidated Balance Sheets at December 31, 2016 and 2015. Progress Energy Progress Energy's Goodwill is included in the Electric Utilities and Infrastructure operating segment and there are no accumulated impairment charges. Impairment Testing Duke Energy, Duke Energy Ohio and Progress Energy perform annual goodwill impairment tests each year as of August 31. Duke Energy, Duke Energy Ohio and Progress Energy update their test between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. As the fair value of Duke Energy, Duke Energy Ohio and Progress Energy’s reporting units exceeded their respective carrying values at the date of the annual impairment analysis, no impairment charges were recorded. Intangible Assets The following tables show the carrying amount and accumulated amortization of intangible assets included in Other within Investments and Other Assets on the Consolidated Balance Sheets of the Duke Energy Registrants at December 31, 2016 and 2015 . December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Emission allowances $ 19 $ 1 $ 6 $ 2 $ 4 $ — $ 13 Renewable energy certificates 125 36 84 84 — 4 — Gas, coal and power contracts 24 — — — — — 24 Renewable operating and development projects 97 — — — — — — Other 6 — — — — — — Total gross carrying amounts 271 37 90 86 4 4 37 Accumulated amortization – gas, coal and power contracts (17 ) — — — — — (17 ) Accumulated amortization – renewable operating and development projects (23 ) — — — — — — Accumulated amortization – other (5 ) — — — — — — Total accumulated amortization (45 ) — — — — — (17 ) Total intangible assets, net $ 226 $ 37 $ 90 $ 86 $ 4 $ 4 $ 20 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Emission allowances $ 20 $ 1 $ 6 $ 2 $ 4 $ — $ 14 Renewable energy certificates 116 30 80 80 — 5 — Gas, coal and power contracts 24 — — — — — 24 Renewable operating and development projects 115 — — — — — — Other 2 — — — — — — Total gross carrying amounts 277 31 86 82 4 5 38 Accumulated amortization – gas, coal and power contracts (16 ) — — — — — (16 ) Accumulated amortization – renewable operating and development projects (18 ) — — — — — — Accumulated amortization – other (1 ) — — — — — — Total accumulated amortization (35 ) — — — — — (16 ) Total intangible assets, net $ 242 $ 31 $ 86 $ 82 $ 4 $ 5 $ 22 Amortization Expense The following table presents amortization expense for gas, coal and power contracts, renewable operating projects and other intangible assets. December 31, (in millions) 2016 2015 2014 Duke Energy $ 6 $ 5 $ 6 Duke Energy Ohio — — 2 Duke Energy Indiana 1 1 1 The table below shows the expected amortization expense for the next five years for intangible assets as of December 31, 2016 . The expected amortization expense includes estimates of emission allowances consumption and estimates of consumption of commodities such as gas and coal under existing contracts, as well as estimated amortization related to renewable operating projects. The amortization amounts discussed below are estimates and actual amounts may differ from these estimates due to such factors as changes in consumption patterns, sales or impairments of emission allowances or other intangible assets, delays in the in-service dates of renewable assets, additional intangible acquisitions and other events. (in millions) 2017 2018 2019 2020 2021 Duke Energy $ 5 $ 5 $ 5 $ 5 $ 5 Duke Energy Indiana 2 2 2 2 2

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investment in Unconsolidated Affiliates	INVESTMENTS IN UNCONSOLIDATED AFFILIATES EQUITY METHOD INVESTMENTS Investments in domestic and international affiliates that are not controlled by Duke Energy, but over which it has significant influence, are accounted for using the equity method. As of December 31, 2016 , the carrying amount of investments in affiliates with carrying amounts greater than zero exceeded the underlying investment by $24 million . These differences are attributable to intangibles associated with underlying contracts which are reflected in the investments balance and the equity in earnings reported in the table below. The following table presents Duke Energy’s investments in unconsolidated affiliates accounted for under the equity method, as well as the respective equity in earnings, by segment. Years Ended December 31, 2016 2015 2014 Equity in Equity in Equity in (in millions) Investments earnings Investments earnings earnings Electric Utilities and Infrastructure $ 93 $ 5 $ 57 $ (2 ) $ (1 ) Gas Utilities and Infrastructure 566 19 113 1 — Commercial Renewables 185 (82 ) 265 (6 ) 8 Other 81 43 64 76 123 Total $ 925 $ (15 ) $ 499 $ 69 $ 130 During the years ended December 31, 2016 , 2015 and 2014 , Duke Energy received distributions from equity investments of $31 million , $104 million and $154 million , respectively, which are included in Other assets within Cash Flows from Operating Activities on the Consolidated Statements of Cash Flows. Significant investments in affiliates accounted for under the equity method are discussed below. Electric Utilities and Infrastructure Duke Energy owns a 50 percent interest in Duke-American Transmission Co. (DATC) and in Pioneer Transmission, LLC (Pioneer), which build, own and operate electric transmission facilities in North America. Gas Utilities and Infrastructure The table below outlines Duke Energy's ownership interests in natural gas pipeline companies and natural gas storage facilities. See Notes 4 and 17 for more information. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2016 2015 Pipeline Investments Atlantic Coast Pipeline, LLC 47 % $ 265 $ 52 Sabal Trail Transmission, LLC 7.5 % 140 61 Constitution Pipeline, LLC 24 % 82 — Cardinal Pipeline Company, LLC 21.49 % 16 — Storage Facilities Pine Needle LNG Company, LLC 45 % 16 — Hardy Storage Company, LLC 50 % 47 — Total Investments $ 566 $ 113 For regulatory matters and other information on the ACP, Sabal Trail and Constitution investments, see Notes 4 and 17. Commercial Renewables In 2016, Duke Energy sold its interest in three of the Catamount Sweetwater, LLC wind farm projects. Duke Energy has a 47 percent ownership interest in each of the two other Catamount Sweetwater, LLC wind farm projects and 50 percent interest in DS Cornerstone, LLC, which owns wind farm projects in the U.S. Impairment of Equity Method Investments During the year ended December 31, 2016, Duke Energy recorded an OTTI of certain wind project investments. The $71 million pretax impairment was recorded within Equity in earnings (losses) of unconsolidated affiliates on Duke Energy's Consolidated Statements of Operations. The other-than-temporary decline in value of these investments was primarily attributable to a sustained decline in market pricing where the wind investments are located, projected net losses for the projects and a reduction in the projected cash distribution to the class of investment owned by Duke Energy. Other Duke Energy owns a 25 percent indirect interest in NMC, which owns and operates a methanol and MTBE business in Jubail, Saudi Arabia. Duke Energy's economic ownership interest will decrease to 17.5 percent upon successful startup of NMC's polyacetal production facility, which is expected to occur in the second quarter of 2017. Duke Energy will retain 25 percent of the board representation and voting rights of NMC. The investment in NMC is accounted for under the equity method of accounting.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with the applicable state and federal commission regulations. Refer to the Consolidated Balance Sheets of the Subsidiary Registrants for balances due to or due from related parties. Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. In addition to the amounts presented above, the Subsidiary Registrants record the impact on net income of other affiliate transactions, including rental of office space, participation in a money pool arrangement, other operational transactions and their proportionate share of certain charged expenses. See Note 6 for more information regarding money pool. The net impact of these transactions was not material for the years ended December 31, 2016 , 2015 and 2014 for the Subsidiary Registrants. As discussed in Note 17 , certain trade receivables have been sold by Duke Energy Ohio and Duke Energy Indiana to CRC, an affiliate formed by a subsidiary of Duke Energy. The proceeds obtained from the sales of receivables are largely cash but do include a subordinated note from CRC for a portion of the purchase price. Duke Energy Ohio's nonregulated indirect subsidiary, Duke Energy Commercial Asset Management, LLC (DECAM), owned generating plants included in the Midwest Generation Disposal Group sold to Dynegy on April 2, 2015. On April 1, 2015, Duke Energy Ohio distributed its indirect ownership interest in DECAM to a Duke Energy subsidiary and non-cash settled DECAM's intercompany loan payable of $294 million . Refer to Note 2 for further information on the sale of the Midwest Generation Disposal Group. Intercompany Income Taxes Duke Energy and its subsidiaries file a consolidated federal income tax return and other state and jurisdictional returns. The Subsidiary Registrants have a tax sharing agreement with Duke Energy for the allocation of consolidated tax liabilities and benefits. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging

Derivatives and Hedging	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price risk and interest rate risk. The primary use of commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Interest rate swaps are used to manage interest rate risk associated with borrowings. All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting arrangements is offset against the collateralized derivatives on the Consolidated Balance Sheets. The cash impacts of settled derivatives are recorded as operating activities on the Consolidated Statements of Cash Flows. INTEREST RATE RISK The Duke Energy Registrants are exposed to changes in interest rates as a result of their issuance or anticipated issuance of variable-rate and fixed-rate debt and commercial paper. Interest rate risk is managed by limiting variable-rate exposures to a percentage of total debt and by monitoring changes in interest rates. To manage risk associated with changes in interest rates, the Duke Energy Registrants may enter into interest rate swaps, U.S. Treasury lock agreements and other financial contracts. In anticipation of certain fixed-rate debt issuances, a series of forward-starting interest rate swaps may be executed to lock in components of current market interest rates. These instruments are later terminated prior to or upon the issuance of the corresponding debt. Cash Flow Hedges For a derivative designated as hedging the exposure to variable cash flows of a future transaction, referred to as a cash flow hedge, the effective portion of the derivative's gain or loss is initially reported as a component of other comprehensive income and subsequently reclassified into earnings once the future transaction impacts earnings. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. See the Consolidated Statements of Changes in Equity for gains and losses reclassified out of AOCI for the years ended December 31, 2016 and 2015 . Duke Energy's interest rate derivatives designated as hedges include interest rate swaps used to hedge existing debt within the Commercial Renewables business. Undesignated Contracts Undesignated contracts include contracts not designated as a hedge because they are accounted for under regulatory accounting and contracts that do not qualify for hedge accounting. Duke Energy’s interest rate swaps for its regulated operations employ regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the swaps are deferred as regulatory liabilities or regulatory assets, respectively. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The accrual of interest on the swaps is recorded as Interest Expense. In August 2016, Duke Energy unwound $1.4 billion of forward-starting interest rate swaps associated with the Piedmont acquisition financing described in Note 6. The swaps were considered undesignated as they did not qualify for hedge accounting. Losses on the swaps of $190 million are included within Interest Expense on the Consolidated Statements of Operations for the year ended December 31, 2016. See Note 2 for additional information related to the Piedmont acquisition. The following tables show notional amounts of outstanding derivatives related to interest rate risk. December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 750 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,677 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 497 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,324 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $750 million and $497 million at December 31, 2016 and 2015 , respectively. The December 31, 2016, amount includes interest rate swaps related to solar facilities financing with an outstanding notional amount of $300 million , including $81 million of four-year swaps and $219 million of 18-year swaps. See note 6 for additional information related to the solar facilities financing. COMMODITY PRICE RISK The Duke Energy Registrants are exposed to the impact of changes in the prices of electricity purchased and sold in bulk power markets and coal and natural gas purchases. Exposure to commodity price risk is influenced by a number of factors including the term of contracts, the liquidity of markets and delivery locations. For the Subsidiary Registrants, bulk power electricity and coal and natural gas purchases flow through fuel adjustment clauses, formula based contracts or other cost sharing mechanisms. Differences between the costs included in rates and the incurred costs, including undesignated derivative contracts, are largely deferred as regulatory assets or regulatory liabilities. Piedmont policies allow for the use of financial instruments to hedge commodity price risks, but not for speculative trading. The strategy and objective of these hedging programs are to use the financial instruments to reduce gas cost volatility for customers. Volumes The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 147 — — — — — 147 Natural gas (millions of dekatherms) (a) 890 91 269 118 151 — 1 (a) Amounts at Duke Energy increased 529 million dekatherms due to the acquisition of Piedmont in 2016. December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of dekatherms) 398 66 332 117 215 — — LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED IN THE CONSOLIDATED BALANCE SHEETS The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 108 $ 23 $ 61 $ 35 $ 26 $ 4 $ 16 Noncurrent 32 10 21 10 11 1 — Total Derivative Assets – Commodity Contracts $ 140 $ 33 $ 82 $ 45 $ 37 $ 5 $ 16 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 19 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 3 — 3 1 2 — — Total Derivative Assets – Interest Rate Contracts $ 22 $ — $ 3 $ 1 $ 2 $ — $ — Total Derivative Assets $ 162 $ 33 $ 85 $ 46 $ 39 $ 5 $ 16 Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 43 $ — $ 12 $ — $ 12 $ — $ 2 Noncurrent 166 1 7 1 — — — Total Derivative Liabilities – Commodity Contracts $ 209 $ 1 $ 19 $ 1 $ 12 $ — $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 8 $ — $ — $ — $ — $ — $ — Noncurrent 8 — — — — — — Not Designated as Hedging Instruments Current 1 — — — — 1 — Noncurrent 26 15 6 6 — 5 — Total Derivative Liabilities – Interest Rate Contracts $ 43 $ 15 $ 6 $ 6 $ — $ 6 $ — Total Derivative Liabilities $ 252 $ 16 $ 25 $ 7 $ 12 $ 6 $ 2 Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 3 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 9 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 25 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 9 $ — $ — $ — $ — $ — $ — Noncurrent 13 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 41 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 397 $ 45 $ 322 $ 98 $ 216 $ 7 $ — OFFSETTING ASSETS AND LIABILITIES The following tables present the line items on the Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 111 $ 23 $ 64 $ 36 $ 28 $ 4 $ 16 Gross amounts offset (11 ) — (11 ) — (11 ) — — Net amounts presented in Current Assets: Other $ 100 $ 23 $ 53 $ 36 $ 17 $ 4 $ 16 Noncurrent Gross amounts recognized $ 51 $ 10 $ 21 $ 10 $ 11 $ 1 $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Investments and Other Assets: Other $ 49 $ 9 $ 20 $ 9 $ 11 $ 1 $ — Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 52 $ — $ 12 $ — $ 12 $ 1 $ 2 Gross amounts offset (11 ) — (11 ) — (11 ) — — Net amounts presented in Current Liabilities: Other $ 41 $ — $ 1 $ — $ 1 $ 1 $ 2 Noncurrent Gross amounts recognized $ 200 $ 16 $ 13 $ 7 $ — $ 5 $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 198 $ 15 $ 12 $ 6 $ — $ 5 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 7 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 3 $ — $ — $ — $ — $ — $ — Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 269 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 247 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 128 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 112 $ 13 $ 82 $ 21 $ 56 $ 6 $ — OBJECTIVE CREDIT CONTINGENT FEATURES Certain derivative contracts contain objective credit contingent features. These features include the requirement to post cash collateral or letters of credit if specific events occur, such as a credit rating downgrade below investment grade. The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio and Duke Energy Indiana were not material. December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 34 $ 16 $ 18 $ 6 $ 12 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 34 16 18 6 12 December 31, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement. At December 31, 2015, receivables of $30 million at Duke Energy Florida related to the right to reclaim cash collateral under master netting arrangements were offset against net derivative positions on the Consolidated Balance Sheets of Duke Energy, Progress Energy and Duke Energy Florida.

Investments in Debt and Equity

Investments in Debt and Equity Securities	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES TRADING SECURITIES Investments in debt and equity securities held in rabbi trusts associated with certain deferred compensation plans are classified as trading securities. The fair value of these investments was $5 million at December 31, 2016 . AVAILABLE-FOR-SALE SECURITIES The Duke Energy Registrants classify their investments in debt and equity securities as available-for-sale. Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the NDTF at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to OPEB plans and (iii) Bison. Duke Energy classifies all other investments in debt and equity securities as long-term, unless otherwise noted. Investment Trusts The investments within the NDTF investments and the Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana grantor trusts (Investment Trusts) are managed by independent investment managers with discretion to buy, sell and invest pursuant to the objectives set forth by the trust agreements. The Duke Energy Registrants have limited oversight of the day-to-day management of these investments. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt and equity securities within the Investment Trusts are considered OTTIs and are recognized immediately. Investments within the Investment Trusts generally qualify for regulatory accounting and accordingly realized and unrealized gains and losses are generally deferred as a regulatory asset or liability. Other Available-for-Sale Securities Unrealized gains and losses on all other available-for-sale securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. If an OTTI exists, the unrealized loss is included in earnings based on the criteria discussed below. The Duke Energy Registrants analyze all investment holdings each reporting period to determine whether a decline in fair value should be considered other-than-temporary. Criteria used to evaluate whether an impairment associated with equity securities is other-than-temporary includes, but is not limited to, (i) the length of time over which the market value has been lower than the cost basis of the investment, (ii) the percentage decline compared to the cost of the investment and (iii) management’s intent and ability to retain its investment for a period of time sufficient to allow for any anticipated recovery in market value. If a decline in fair value is determined to be other-than-temporary, the investment is written down to its fair value through a charge to earnings. If the entity does not have an intent to sell a debt security and it is not more likely than not management will be required to sell the debt security before the recovery of its cost basis, the impairment write-down to fair value would be recorded as a component of other comprehensive income, except for when it is determined a credit loss exists. In determining whether a credit loss exists, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than the amortized cost basis, (ii) changes in the financial condition of the issuer of the security, or in the case of an asset backed security, the financial condition of the underlying loan obligors, (iii) consideration of underlying collateral and guarantees of amounts by government entities, (iv) ability of the issuer of the security to make scheduled interest or principal payments and (v) any changes to the rating of the security by rating agencies. If a credit loss exists, the amount of impairment write-down to fair value is split between credit loss and other factors. The amount related to credit loss is recognized in earnings. The amount related to other factors is recognized in other comprehensive income. There were no material credit losses as of December 31, 2016 and 2015 . DUKE ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 111 $ — $ — $ 179 Equity securities 2,092 54 4,106 1,823 58 3,590 Corporate debt securities 10 8 528 7 8 432 Municipal bonds 3 10 331 5 1 185 U.S. government bonds 10 8 984 11 5 1,254 Other debt securities — 3 124 — 4 177 Total NDTF $ 2,115 $ 83 $ 6,184 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 25 $ — $ — $ 29 Equity securities 38 — 104 32 1 95 Corporate debt securities 1 1 66 1 3 92 Municipal bonds 2 1 82 3 1 74 U.S. government bonds — 1 51 — — 45 Other debt securities — 2 42 — 2 62 Total Other Investments (b) $ 41 $ 5 $ 370 $ 36 $ 7 $ 397 Total Investments $ 2,156 $ 88 $ 6,554 $ 1,882 $ 83 $ 6,214 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 94 Due after one through five years 653 Due after five through 10 years 515 Due after 10 years 946 Total $ 2,208 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 246 $ 193 $ 271 Realized losses 187 98 105 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 18 $ — $ — $ 34 Equity securities 1,157 28 2,245 1,021 27 2,094 Corporate debt securities 5 6 354 3 5 292 Municipal bonds 1 2 67 1 — 33 U.S. government bonds 2 5 458 3 3 438 Other debt securities — 3 116 — 4 147 Total NDTF $ 1,165 $ 44 $ 3,258 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (b) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,165 $ 45 $ 3,261 $ 1,028 $ 40 $ 3,041 (a) Substantially all these amounts represent OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 3 Due after one through five years 230 Due after five through 10 years 260 Due after 10 years 505 Total $ 998 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 157 $ 158 $ 109 Realized losses 121 83 93 PROGRESS ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 93 $ — $ — $ 145 Equity securities 935 26 1,861 802 31 1,496 Corporate debt securities 5 2 174 4 3 140 Municipal bonds 2 8 264 4 1 152 U.S. government bonds 8 3 526 8 2 816 Other debt securities — — 8 — — 30 Total NDTF $ 950 $ 39 $ 2,926 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 21 $ — $ — $ 18 Municipal bonds 2 — 44 3 — 45 Total Other Investments (b) $ 2 $ — $ 65 $ 3 $ — $ 63 Total Investments $ 952 $ 39 $ 2,991 $ 821 $ 37 $ 2,842 (a) Substantially all these amounts represent OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 84 Due after one through five years 347 Due after five through 10 years 187 Due after 10 years 398 Total $ 1,016 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 84 $ 33 $ 157 Realized losses 64 13 11 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 45 $ — $ — $ 110 Equity securities 704 21 1,505 596 25 1,178 Corporate debt securities 4 1 120 3 2 96 Municipal bonds 2 8 263 4 1 150 U.S. government bonds 5 2 275 6 2 486 Other debt securities — — 5 — — 18 Total NDTF $ 715 $ 32 $ 2,213 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (b) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 715 $ 32 $ 2,214 $ 609 $ 30 $ 2,039 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 28 Due after one through five years 190 Due after five through 10 years 142 Due after 10 years 303 Total $ 663 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 71 $ 26 $ 19 Realized losses 55 11 5 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 48 $ — $ — $ 35 Equity securities 231 5 356 206 6 318 Corporate debt securities 1 1 54 1 1 44 Municipal bonds — — 1 — — 2 U.S. government bonds 3 1 251 2 — 330 Other debt securities — — 3 — — 12 Total NDTF (b) $ 235 $ 7 $ 713 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 6 Municipal bonds 2 — 44 3 — 45 Total Other Investments (c) $ 2 $ — $ 48 $ 3 $ — $ 51 Total Investments $ 237 $ 7 $ 761 $ 212 $ 7 $ 792 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) The decrease in estimated fair value of the NDTF as of December 31, 2016 , is primarily due to reimbursements from the NDTF for costs related to ongoing decommissioning activity of Crystal River Unit 3. (c) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 56 Due after one through five years 157 Due after five through 10 years 45 Due after 10 years 95 Total $ 353 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 13 $ 7 $ 138 Realized losses 9 2 5 DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value Other Investments Cash and cash equivalents $ — $ — $ — $ — $ — $ 2 Equity securities 33 — 79 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds — 1 28 — 1 26 U.S. government bonds — — 1 — — — Total Other Investments (b) $ 33 $ 1 $ 110 $ 27 $ 1 $ 101 Total Investments $ 33 $ 1 $ 110 $ 27 $ 1 $ 101 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets. The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 3 Due after one through five years 13 Due after five through 10 years 9 Due after 10 years 6 Total $ 31 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were insignificant for the years ended December 31, 2016 , 2015 and 2014 .

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data, or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient. Fair value measurements are classified in three levels based on the fair value hierarchy: Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. An active market is one in which transactions for an asset or liability occur with sufficient frequency and volume to provide ongoing pricing information. Level 2 – A fair value measurement utilizing inputs other than quoted prices included in Level 1 that are observable, either directly or indirectly, for an asset or liability. Inputs include (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active, (iii) and inputs other than quoted market prices that are observable for the asset or liability, such as interest rate curves and yield curves observable at commonly quoted intervals, volatilities and credit spreads. A Level 2 measurement cannot have more than an insignificant portion of its valuation based on unobservable inputs. Instruments in this category include non-exchange-traded derivatives, such as over-the-counter forwards, swaps and options; certain marketable debt securities; and financial instruments traded in less than active markets. Level 3 – Any fair value measurement which includes unobservable inputs for more than an insignificant portion of the valuation. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value. Level 3 measurements may include longer-term instruments that extend into periods in which observable inputs are not available. Not Categorized – Certain investments are not categorized within the Fair Value hierarchy. These investments are measured based on the fair value of the underlying investments but may not be readily redeemable at that fair value. Fair value accounting guidance permits entities to elect to measure certain financial instruments that are not required to be accounted for at fair value, such as equity method investments or the company’s own debt, at fair value. The Duke Energy Registrants have not elected to record any of these items at fair value. Transfers between levels represent assets or liabilities that were previously (i) categorized at a higher level for which the inputs to the estimate became less observable or (ii) classified at a lower level for which the inputs became more observable during the period. The Duke Energy Registrant’s policy is to recognize transfers between levels of the fair value hierarchy at the end of the period. There were no transfers between Levels 1 and 2 during the years ended December 31, 2016 , 2015 and 2014 . Transfers out of Level 3 during the year ended December 31, 2014, were the result of forward commodity prices becoming observable due to the passage of time. Valuation methods of the primary fair value measurements disclosed below are as follows. Investments in equity securities The majority of investments in equity securities are valued using Level 1 measurements. Investments in equity securities are typically valued at the closing price in the principal active market as of the last business day of the quarter. Principal active markets for equity prices include published exchanges such as the New York Stock Exchange (NYSE) and the NASDAQ Stock Market. Foreign equity prices are translated from their trading currency using the currency exchange rate in effect at the close of the principal active market. There was no after-hours market activity that was required to be reflected in the reported fair value measurements. Investments in debt securities Most investments in debt securities are valued using Level 2 measurements because the valuations use interest rate curves and credit spreads applied to the terms of the debt instrument (maturity and coupon interest rate) and consider the counterparty credit rating. If the market for a particular fixed-income security is relatively inactive or illiquid, the measurement is Level 3. Commodity derivatives Commodity derivatives with clearinghouses are classified as Level 1. Other commodity derivatives are primarily valued using internally developed discounted cash flow models which incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or non-performance risk (after reflecting credit enhancements such as collateral) and are discounted to present value. Pricing inputs are derived from published exchange transaction prices and other observable data sources. In the absence of an active market, the last available price may be used. If forward price curves are not observable for the full term of the contract and the unobservable period had more than an insignificant impact on the valuation, the commodity derivative is classified as Level 3. In isolation, increases (decreases) in natural gas forward prices result in favorable (unfavorable) fair value adjustments for gas purchase contracts; and increases (decreases) in electricity forward prices result in unfavorable (favorable) fair value adjustments for electricity sales contracts. Duke Energy regularly evaluates and validates pricing inputs used to estimate the fair value of gas commodity contracts by a market participant price verification procedure. This procedure provides a comparison of internal forward commodity curves to market participant generated curves. Interest rate derivatives Most over-the-counter interest rate contract derivatives are valued using financial models which utilize observable inputs for similar instruments and are classified as Level 2. Inputs include forward interest rate curves, notional amounts, interest rates and credit quality of the counterparties. Other fair value considerations See Note 11 for a discussion of the valuation of goodwill and intangible assets. See Note 2 related to the acquisition of Piedmont in 2016 and the purchase of NCEMPA's ownership interests in certain generating assets in 2015. DUKE ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 4,106 $ 4,029 $ — $ — $ 77 Nuclear decommissioning trust fund debt securities 2,078 632 1,446 — — Other trading and available-for-sale equity securities 104 104 — — — Other trading and available-for-sale debt securities 266 75 186 5 — Derivative assets 162 5 136 21 — Total assets 6,716 4,845 1,768 26 77 Derivative liabilities (252 ) (2 ) (63 ) (187 ) — Net assets (liabilities) $ 6,464 $ 4,843 $ 1,705 $ (161 ) $ 77 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 — Derivative assets 25 — 15 10 — Total assets 6,239 4,260 1,792 15 172 Derivative liabilities (397 ) — (397 ) — — Net assets $ 5,842 $ 4,260 $ 1,395 $ 15 $ 172 The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues. December 31, 2016 Derivatives (in millions) Investments (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Derivative liability resulting from the acquisition of Piedmont — (187 ) (187 ) Purchases, sales, issuances and settlements: Purchases — 33 33 Settlements — (28 ) (28 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities — 6 6 Balance at end of period $ 5 $ (166 ) $ (161 ) December 31, 2015 Derivatives (in millions) Investments (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains (losses) included in earnings — 21 21 Purchases, sales, issuances and settlements: Purchases — 24 24 Sales — (1 ) (1 ) Settlements — (37 ) (37 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities — 4 4 Balance at end of period $ 5 $ 10 $ 15 DUKE ENERGY CAROLINAS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 2,245 $ 2,168 $ — $ — $ 77 Nuclear decommissioning trust fund debt securities 1,013 178 835 — — Other available-for-sale debt securities 3 — — 3 — Derivative assets 33 — 33 — — Total assets 3,294 2,346 868 3 77 Derivative liabilities (16 ) — (16 ) — — Net assets $ 3,278 $ 2,346 $ 852 $ 3 $ 77 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — — Other available-for-sale debt securities 3 — — 3 — Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172 There was no change to the Level 3 balance during the years ended December 31, 2016 and 2015 . PROGRESS ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,861 $ 1,861 $ — Nuclear decommissioning trust fund debt securities 1,065 454 611 Other available-for-sale debt securities 65 21 44 Derivative assets 85 — 85 Total assets 3,076 2,336 740 Derivative liabilities (25 ) — (25 ) Net assets $ 3,051 $ 2,336 $ 715 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591 DUKE ENERGY PROGRESS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,505 $ 1,505 $ — Nuclear decommissioning trust fund debt securities and other 708 207 501 Other available-for-sale debt securities and other 1 1 — Derivative assets 46 — 46 Total assets 2,260 1,713 547 Derivative liabilities (7 ) — (7 ) Net assets $ 2,253 $ 1,713 $ 540 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623 DUKE ENERGY FLORIDA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 356 $ 356 $ — Nuclear decommissioning trust fund debt securities and other 357 247 110 Other available-for-sale debt securities and other 48 4 44 Derivative assets 39 — 39 Total assets 800 607 193 Derivative liabilities (12 ) — (12 ) Net assets $ 788 $ 607 $ 181 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 ) DUKE ENERGY OHIO The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which are disclosed in Note 14 . December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 5 $ — $ — $ 5 Derivative liabilities (6 ) — (6 ) — Net (liabilities) assets $ (1 ) $ — $ (6 ) $ 5 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains (losses) included in earnings — 21 Purchases, sales, issuances and settlements: Purchases 5 5 Settlements (5 ) (5 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities 2 — Balance at end of period $ 5 $ 3 DUKE ENERGY INDIANA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 79 $ 79 $ — $ — Other available-for-sale debt securities and other 31 — 31 — Derivative assets 16 — — 16 Total assets 126 79 31 16 Derivative liabilities (2 ) (2 ) — — Net assets $ 124 $ 77 $ 31 $ 16 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Purchases, sales, issuances and settlements: Purchases 29 19 Settlements (24 ) (30 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities 4 4 Balance at end of period $ 16 $ 7 QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. December 31, 2016 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Natural gas contracts $ (187 ) Discounted cash flow Forward natural gas curves - price per million British thermal unit (MMBtu) $ 2.31 - $ 4.18 Financial Transmission Rights (FTRs) 21 RTO auction pricing FTR price – per megawatt-hour (MWh) (0.83 ) - 9.32 Total Level 3 derivatives $ (166 ) Duke Energy Ohio $ 5 RTO auction pricing FTR price – per MWh $ 0.77 - $ 3.52 Duke Energy Indiana 16 RTO auction pricing FTR price – per MWh (0.83 ) - 9.32 December 31, 2015 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29 OTHER FAIR VALUE DISCLOSURES The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. December 31, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 47,895 $ 49,161 $ 38,868 $ 41,767 Duke Energy Carolinas 9,603 10,494 8,367 9,156 Progress Energy 17,541 19,107 14,464 15,856 Duke Energy Progress 7,011 7,357 6,518 6,757 Duke Energy Florida 6,125 6,728 4,266 4,908 Duke Energy Ohio 1,884 2,020 1,598 1,724 Duke Energy Indiana 3,786 4,260 3,768 4,219 At both December 31, 2016 and December 31, 2015 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper and non-recourse notes payable of VIEs are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2016
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES A VIE is an entity that is evaluated for consolidation using more than a simple analysis of voting control. The analysis to determine whether an entity is a VIE considers contracts with an entity, credit support for an entity, the adequacy of the equity investment of an entity and the relationship of voting power to the amount of equity invested in an entity. This analysis is performed either upon the creation of a legal entity or upon the occurrence of an event requiring reevaluation, such as a significant change in an entity’s assets or activities. A qualitative analysis of control determines the party that consolidates a VIE. This assessment is based on (i) what party has the power to direct the activities of the VIE that most significantly impact its economic performance and (ii) what party has rights to receive benefits or is obligated to absorb losses that could potentially be significant to the VIE. The analysis of the party that consolidates a VIE is a continual reassessment. CONSOLIDATED VIEs The obligations of these VIEs discussed in the following paragraphs are nonrecourse to the Duke Energy Registrants. The registrants have no requirement to provide liquidity to, purchase assets of or guarantee performance of these VIEs unless noted in the following paragraphs. No financial support was provided to any of the consolidated VIEs during the years ended December 31, 2016 , 2015 and 2014 , or is expected to be provided in the future, that was not previously contractually required. Receivables Financing – DERF/DEPR/DEFR Duke Energy Receivables Finance Company, LLC (DERF), Duke Energy Progress Receivables, LLC (DEPR) and Duke Energy Florida Receivables, LLC (DEFR) are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. DERF, DEPR and DEFR are wholly owned limited liability companies with separate legal existence from their parent companies and their assets are not generally available to creditors of their parent companies. On a revolving basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and related services from their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy these receivables. Borrowing availability from the credit facilities is limited to the amount of qualified receivables purchased. The sole source of funds to satisfy the related debt obligations is cash collections from the receivables. Amounts borrowed under the credit facilities are reflected on the Consolidated Balance Sheets as Long-Term Debt. The most significant activity that impacts the economic performance of DERF, DEPR and DEFR are the decisions made to manage delinquent receivables. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida consolidate DERF, DEPR and DEFR, respectively, as they make those decisions. Receivables Financing – CRC CRC is a bankruptcy remote, special purpose entity indirectly owned by Duke Energy. On a revolving basis, CRC buys certain accounts receivable arising from the sale of electricity, natural gas and related services from Duke Energy Ohio and Duke Energy Indiana. CRC borrows amounts under a credit facility to buy the receivables from Duke Energy Ohio and Duke Energy Indiana. Borrowing availability from the credit facility is limited to the amount of qualified receivables sold to CRC. The sole source of funds to satisfy the related debt obligation is cash collections from the receivables. Amounts borrowed under the credit facility are reflected on Duke Energy's Consolidated Balance Sheets as Long-Term Debt. The proceeds Duke Energy Ohio and Duke Energy Indiana receive from the sale of receivables to CRC are typically 75 percent cash and 25 percent in the form of a subordinated note from CRC. The subordinated note is a retained interest in the receivables sold. Depending on collection experience, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million . CRC is considered a VIE because (i) equity capitalization is insufficient to support its operations, (ii) power to direct the activities that most significantly impact the economic performance of the entity are not performed by the equity holder and (iii) deficiencies in net worth of CRC are funded by Duke Energy. The most significant activities that impact the economic performance of CRC are decisions made to manage delinquent receivables. Duke Energy consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC. Receivables Financing – Credit Facilities The following table outlines amounts and expiration dates of the credit facilities described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount (in millions) $ 325 $ 425 $ 300 $ 225 Amounts borrowed at December 31, 2016 325 425 300 225 Amounts borrowed at December 31, 2015 325 425 254 225 Nuclear Asset-Recovery Bonds – DEFPF DEFPF is a bankruptcy remote, wholly owned special purpose subsidiary of Duke Energy Florida. DEFPF was formed in 2016 for the sole purpose of issuing nuclear asset-recovery bonds to finance Duke Energy Florida's unrecovered regulatory asset related to Crystal River Unit 3. In June 2016, DEFPF issued $1,294 million of senior secured bonds and used the proceeds to acquire nuclear asset-recovery property from Duke Energy Florida. The nuclear asset-recovery property acquired includes the right to impose, bill, collect and adjust a non-bypassable nuclear asset-recovery charge from all Duke Energy Florida retail customers until the bonds are paid in full and all financing costs have been recovered. The nuclear asset-recovery bonds are secured by the nuclear asset-recovery property and cash collections from the nuclear asset-recovery charges are the sole source of funds to satisfy the debt obligation. The bondholders have no recourse to Duke Energy Florida. For additional information see Notes 4 and 6 . DEFPF is considered a VIE primarily because the equity capitalization is insufficient to support its operations. Duke Energy Florida has the power to direct the significant activities of the VIE as described above and therefore Duke Energy Florida is considered the primary beneficiary and consolidates DEFPF. The following table summarizes the impact of DEFPF on Duke Energy Florida's Consolidated Balance Sheets. (in millions) December 31, 2016 Receivables of VIEs $ 6 Regulatory Assets: Current 50 Current Assets: Other 53 Regulatory Assets and Deferred Debits: Regulatory assets 1,142 Current Liabilities: Other 17 Current maturities of long-term debt 62 Long-Term Debt 1,217 Commercial Renewables Certain of Duke Energy’s renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Assets are restricted and cannot be pledged as collateral or sold to third parties without prior approval of debt holders. The activities that most significantly impact the economic performance of these renewable energy facilities were decisions associated with siting, negotiating PPAs, engineering, procurement and construction and decisions associated with ongoing operations and maintenance-related activities. Duke Energy consolidates the entities as it is responsible for all of these decisions. The table below presents material balances reported on Duke Energy's Consolidated Balance Sheets related to renewables VIEs. (in millions) December 31, 2016 December 31, 2015 Current Assets: Other $ 223 $ 138 Property, plant and equipment, cost 3,419 2,015 Accumulated depreciation and amortization (453 ) (321 ) Current maturities of long-term debt 198 108 Long-Term Debt 1,097 968 Deferred Credits and Other Liabilities: Deferred income taxes 275 289 Deferred Credits and Other Liabilities: Other 252 33 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Consolidated Balance Sheets. December 31, 2016 Duke Energy Duke Duke Pipeline Commercial Energy Energy (in millions) Investments Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 82 $ 101 Investments in equity method unconsolidated affiliates 487 174 90 751 — — Investments and other assets 12 — — 12 — — Total assets $ 499 $ 174 $ 90 $ 763 $ 82 $ 101 Other current liabilities — — 3 3 — — Deferred credits and other liabilities — — 13 13 — — Total liabilities $ — $ — $ 16 $ 16 $ — $ — Net assets (liabilities) $ 499 $ 174 $ 74 $ 747 $ 82 $ 101 December 31, 2015 Duke Energy Duke Duke Pipeline Commercial Energy Energy (in millions) Investments Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 113 235 39 387 — Total assets $ 113 $ 235 $ 39 $ 387 $ 47 $ 60 Other current liabilities — — 3 3 — — Deferred credits and other liabilities — — 14 14 — — Total liabilities $ — $ — $ 17 $ 17 $ — $ — Net assets $ 113 $ 235 $ 22 $ 370 $ 47 $ 60 The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the power purchase agreement with OVEC, which is discussed below, and various guarantees, some of which are reflected in the table above as Deferred credits and other liabilities. For more information on various guarantees, refer to Note 7 . Pipeline Investments Duke Energy has investments in various joint ventures with pipeline projects currently under construction. These entities are considered VIEs due to having insufficient equity to finance their own activities without subordinated financial support. Duke Energy does not have the power to direct the activities that most significantly impact the economic performance, the obligation to absorb losses or the right to receive benefits of these VIEs and therefore does not consolidate these entities. The table below presents Duke Energy's ownership interest and investment balance in in these joint ventures. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest (a) 2016 2015 ACP 47 % $ 265 $ 52 Sabal Trail 7.5 % 140 61 Constitution 24 % 82 — Total $ 487 $ 113 (a) The percentages presented reflect Duke Energy's ownership interest as of December 31, 2016. The investment amount presented for ACP as of December 31, 2015, reflects 40 percent ownership interest prior to acquiring an additional 7 percent as a result of the Piedmont acquisition. See Notes 2 and 4 for additional information related to the Piedmont acquisition and increased ownership of ACP. Commercial Renewables Duke Energy has investments in various renewable energy project entities. Some of these entities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Duke Energy does not consolidate these VIEs because power to direct and control key activities is shared jointly by Duke Energy and other owners. During the year ended December 31, 2016, Duke Energy recorded a $71 million pretax OTTI of certain wind project investments within Equity in earnings (losses) of unconsolidated affiliates on Duke Energy's Consolidated Statements of Operations. See Note 12 for additional information related to the OTTI. Other Duke Energy holds a 50 percent equity interest in DATC. DATC is considered a VIE due to having insufficient equity to finance their own activities without subordinated financial support. The activities that most significantly impact DATC's economic performance are decisions related to investing in existing and development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner, American Transmission Company, LLC, therefore Duke Energy does not consolidate DATC. Duke Energy holds a 50 percent equity interest in Pioneer. Pioneer is considered a VIE due to having insufficient equity to finance their own activities without subordinated financial support. The activities that most significantly impact Pioneer's economic performance are decisions related to the development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner, American Electric Power, therefore Duke Energy does not consolidate Pioneer. OVEC Duke Energy Ohio’s 9 percent ownership interest in OVEC is considered a non-consolidated VIE due to having insufficient equity to finance their activities without subordinated financial support. As a counterparty to an inter-company power agreement (ICPA), Duke Energy Ohio has a contractual arrangement to buy power from OVEC’s power plants through June 2040 commensurate with its power participation ratio, which is equivalent to Duke Energy Ohio's ownership interest. Costs, including fuel, operating expenses, fixed costs, debt amortization, and interest expense are allocated to counterparties to the ICPA based on their power participation ratio. The value of the ICPA is subject to variability due to fluctuation in power prices and changes in OVEC's cost of business, including costs associated with its 2,256 MW of coal-fired generation capacity. Deterioration in the credit quality, or bankruptcy of one or more parties to the ICPA could increase the costs of OVEC. In addition, certain proposed environmental rulemaking could result in future increased cost allocations. CRC See discussion under Consolidated VIEs for additional information related to CRC. Amounts included in Receivables from affiliated companies in the above table for Duke Energy Ohio and Duke Energy Indiana reflect their retained interest in receivables sold to CRC. These subordinated notes held by Duke Energy Ohio and Duke Energy Indiana are stated at fair value. Carrying values of retained interests are determined by allocating carrying value of the receivables between assets sold and interests retained based on relative fair value. The allocated bases of the subordinated notes are not materially different than their face value because (i) the receivables generally turnover in less than two months, (ii) credit losses are reasonably predictable due to the broad customer base and lack of significant concentration and (iii) the equity in CRC is subordinate to all retained interests and thus would absorb losses first. The hypothetical effect on fair value of the retained interests assuming both a 10 percent and a 20 percent unfavorable variation in credit losses or discount rates is not material due to the short turnover of receivables and historically low credit loss history. Interest accrues to Duke Energy Ohio and Duke Energy Indiana on the retained interests using the acceptable yield method. This method generally approximates the stated rate on the notes since the allocated basis and the face value are nearly equivalent. An impairment charge is recorded against the carrying value of both retained interests and purchased beneficial interest whenever it is determined that an OTTI has occurred. Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2016 2015 2016 2015 Anticipated credit loss ratio 0.5 % 0.6 % 0.3 % 0.3 % Discount rate 1.5 % 1.2 % 1.5 % 1.2 % Receivable turnover rate 13.3 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) 2016 2015 2016 2015 Receivables sold $ 267 $ 233 $ 306 $ 260 Less: Retained interests 82 47 101 60 Net receivables sold $ 185 $ 186 $ 205 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Years Ended December 31, Years Ended December 31, (in millions) 2016 2015 2014 2016 2015 2014 Sales Receivables sold $ 1,926 $ 1,963 $ 2,246 $ 2,635 $ 2,627 $ 2,913 Loss recognized on sale 9 9 11 11 11 11 Cash Flows Cash proceeds from receivables sold 1,882 1,995 2,261 2,583 2,670 2,932 Collection fees received 1 1 1 1 1 1 Return received on retained interests 2 3 4 5 5 6 Cash flows from the sales of receivables are reflected within Cash Flows From Operating Activities on Duke Energy Ohio’s and Duke Energy Indiana’s Consolidated Statements of Cash Flows. Collection fees received in connection with servicing transferred accounts receivable are included in Operation, maintenance and other on Duke Energy Ohio’s and Duke Energy Indiana’s Consolidated Statements of Operations and Comprehensive Income. The loss recognized on sales of receivables is calculated monthly by multiplying receivables sold during the month by the required discount. The required discount is derived monthly utilizing a three-year weighted average formula that considers charge-off history, late charge history and turnover history on the sold receivables, as well as a component for the time value of money. The discount rate, or component for the time value of money, is the prior month-end LIBOR plus a fixed rate of 1.00 percent .

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Common Stock	COMMON STOCK Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common stockholders, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common stock outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common stock outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options, were exercised or settled. Duke Energy’s participating securities are restricted stock units that are entitled to dividends declared on Duke Energy common stock during the restricted stock unit’s vesting periods. The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common stock outstanding to the diluted weighted average number of common stock outstanding. Years Ended December 31, (in millions, except per share amounts) 2016 2015 2014 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 2,567 $ 2,640 $ 2,529 Weighted average shares outstanding – basic 691 694 707 Weighted average shares outstanding – diluted 691 694 707 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 3.71 3.80 3.58 Diluted $ 3.71 3.80 3.58 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 3.36 3.24 3.15 (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met. Stock Issuance In March 2016, Duke Energy marketed an equity offering of 10.6 million shares of common stock. In lieu of issuing equity at the time of the offering, Duke Energy entered into Equity Forwards with Barclays. The Equity Forwards required Duke Energy to either physically settle the transactions by issuing 10.6 million shares, or net settle in whole or in part through the delivery or receipt of cash or shares. On October 5, 2016, following the close of the Piedmont acquisition, Duke Energy physically settled the Equity Forwards in full by delivering 10.6 million shares of common stock in exchange for net cash proceeds of approximately $723 million . The net proceeds were used to finance a portion of the Piedmont acquisition. Accelerated Stock Repurchase Program On April 6, 2015, Duke Energy entered into agreements with each of Goldman, Sachs & Co. and JPMorgan Chase Bank, National Association (the Dealers) to repurchase a total of $1.5 billion of Duke Energy common stock under an accelerated stock repurchase program (the ASR). Duke Energy made payments of $750 million to each of the Dealers and was delivered 16.6 million shares, with a total fair value of $1.275 billion , which represented approximately 85 percent of the total number of shares of Duke Energy common stock expected to be repurchased under the ASR. The company recorded the $1.5 billion payment as a reduction to common stock as of April 6, 2015. In June 2015, the Dealers delivered 3.2 million additional shares to Duke Energy to complete the ASR. Approximately 19.8 million shares, in total, were delivered to Duke Energy and retired under the ASR at an average price of $75.75 per share. The final number of shares repurchased was based upon the average of the daily volume weighted average stock prices of Duke Energy’s common stock during the term of the program, less a discount.

Severance

Severance	12 Months Ended
	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Severance	SEVERANCE As part of strategic planning processes launched in 2015, Duke Energy continued to implement targeted cost savings initiatives during 2016 aimed at reducing operations and maintenance expense. The initiatives included efforts to reduce costs through the standardization of processes and systems, leveraging technology and workforce optimization throughout the company. Also during 2016, Duke Energy and Piedmont announced severance plans covering certain eligible employees whose employment will be involuntarily terminated without cause as a result of Duke Energy's acquisition of Piedmont. These reductions are a part of the synergies expected to be realized with the acquisition. Refer to Note 2 for additional information on the Piedmont acquisition. As part of the cost savings initiatives and the Piedmont integration, voluntary and involuntary severance benefit costs were accrued for a total of approximately 600 employees in 2016 and 900 employees in 2015. The following table presents the direct and allocated severance and related expenses recorded by the Duke Energy Registrants. Amounts are included within Operation, maintenance and other on the Consolidated Statements of Operations. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Year Ended December 31, 2016 $ 118 $ 39 $ 40 $ 23 $ 17 $ 3 $ 7 Year Ended December 31, 2015 142 93 36 28 8 2 6 The table below presents the severance liability for past and ongoing severance plans including the plans described above. Amounts for Duke Energy Indiana and Duke Energy Ohio are not material. Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Balance at December 31, 2015 $ 136 $ 78 $ 23 $ 19 $ 4 Provision/Adjustments 110 18 20 11 9 Cash Reductions (167 ) (83 ) (29 ) (24 ) (5 ) Balance at December 31, 2016 $ 79 $ 13 $ 14 $ 6 $ 8

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Duke Energy Corporation 2015 Long-Term Incentive Plan (the 2015 Plan) provides for the grant of stock-based compensation awards to employees and outside directors. The 2015 Plan reserves 10 million shares of common stock for issuance. Duke Energy has historically issued new shares upon exercising or vesting of share-based awards. However, Duke Energy may use a combination of new share issuances and open market repurchases for share-based awards that are exercised or vest in the future. Duke Energy has not determined with certainty the amount of such new share issuances or open market repurchases. The following table summarizes the total expense recognized by the Duke Energy Registrants, net of tax, for stock-based compensation. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 35 $ 38 $ 38 Duke Energy Carolinas 12 14 12 Progress Energy 12 14 14 Duke Energy Progress 7 9 9 Duke Energy Florida 5 5 5 Duke Energy Ohio 2 2 5 Duke Energy Indiana 3 4 3 Duke Energy's pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Restricted stock unit awards $ 36 $ 38 $ 39 Performance awards 19 23 22 Pretax stock-based compensation cost $ 55 $ 61 $ 61 Tax benefit associated with stock-based compensation expense $ 20 $ 23 $ 23 Stock-based compensation costs capitalized 2 3 4 RESTRICTED STOCK UNIT AWARDS Restricted stock unit awards generally vest over periods from immediate to three years . Fair value amounts are based on the market price of Duke Energy's common stock on the grant date. The following table includes information related to restricted stock unit awards. Years Ended December 31, 2016 2015 2014 Shares awarded (in thousands) 684 524 557 Fair value (in millions) $ 52 $ 41 $ 40 The following table summarizes information about restricted stock unit awards outstanding. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2015 953 $ 75 Piedmont transfers in 113 79 Granted 684 75 Vested (525 ) 73 Forfeited (86 ) 76 Outstanding at December 31, 2016 1,139 76 Restricted stock unit awards expected to vest 1,056 76 The total grant date fair value of shares vested during the years ended December 31, 2016 , 2015 and 2014 was $38 million , $41 million and $52 million , respectively. At December 31, 2016 , Duke Energy had $27 million of unrecognized compensation cost, which is expected to be recognized over a weighted average period of one year, ten months . PERFORMANCE AWARDS Stock-based performance awards generally vest after three years if performance targets are met. Performance awards granted in 2016, 2015 and 2014 contain market conditions based on the total shareholder return (TSR) of Duke Energy stock relative to a predefined peer group (relative TSR). These awards are valued using a path-dependent model that incorporates expected relative TSR into the fair value determination of Duke Energy’s performance-based share awards. The model uses three-year historical volatilities and correlations for all companies in the predefined peer group, including Duke Energy, to simulate Duke Energy’s relative TSR as of the end of the performance period. For each simulation, Duke Energy’s relative TSR associated with the simulated stock price at the end of the performance period plus expected dividends within the period results in a value per share for the award portfolio. The average of these simulations is the expected portfolio value per share. Actual life to date results of Duke Energy’s relative TSR for each grant are incorporated within the model. For performance awards granted in 2016, the model used a risk-free interest rate of 0.9 percent , which reflects the yield on three-year Treasury bonds as of the grant date, and an expected volatility of 16.1 percent based on Duke Energy's historical volatility over three years using daily stock prices. The performance awards granted in 2016 also contain a performance condition based on Duke Energy's cumulative adjusted EPS. The following table includes information related to stock-based performance awards. Years Ended December 31, 2016 2015 2014 Shares awarded (in thousands) 675 642 542 Fair value (in millions) $ 25 $ 26 $ 19 The following table summarizes information about stock-based performance awards outstanding and assumes payout at the maximum level. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2015 1,697 $ 40 Granted 675 38 Vested (544 ) 46 Forfeited (104 ) 38 Outstanding at December 31, 2016 1,724 38 Stock-based performance awards expected to vest 1,199 38 The total grant date fair value of shares vested during the years ended December 31, 2016 , 2015 and 2014 was $25 million , $26 million and $27 million , respectively. At December 31, 2016 , Duke Energy had $24 million of unrecognized compensation cost, which is expected to be recognized over a weighted average period of one year, ten months . STOCK OPTIONS Stock options are granted with a maximum option term of 10 years and with an exercise price not less than the market price of Duke Energy's common stock on the grant date. The following table summarizes information about stock options outstanding. Weighted Average Stock Options Exercise Price (in thousands) (per share) Outstanding at December 31, 2015 103 $ 69 Exercised (103 ) 69 Outstanding at December 31, 2016 — — The following table summarizes additional information related to stock options exercised and granted. Years Ended December 31, (in millions) 2016 2015 2014 Intrinsic value of options exercised $ 1 $ 5 $ 6 Tax benefit related to options exercised — 2 2 Cash received from options exercised 7 17 25

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy or its affiliates maintain, and the Subsidiary Registrants participate in, qualified, non-contributory defined benefit retirement plans. The plans cover most U.S. employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits based upon a percentage of current eligible earnings based on age, or age and years of service and interest credits. Certain employees are covered under plans that use a final average earnings formula. Under these average earnings formulas, a plan participant accumulates a retirement benefit equal to the sum of percentages of their (i) highest three-year, four-year, or five-year average earnings, (ii) highest three-year, four-year, or five-year average earnings in excess of covered compensation per year of participation (maximum of 35 years ), (iii) highest three-year average earnings times years of participation in excess of 35 years . Duke Energy also maintains, and the Subsidiary Registrants participate in, non-qualified, non-contributory defined benefit retirement plans which cover certain executives. As of January 1, 2014, the qualified and non-qualified non-contributory defined benefit plans are closed to new and rehired non-union and certain unionized employees. Piedmont employees hired or rehired after December 31, 2007, cannot participate in the qualified non-contributory defined benefit plans, but are participants in the Money Purchase Pension (MPP) plan, discussed below. Duke Energy uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. Net periodic benefit costs disclosed in the tables below represent the cost of the respective benefit plan for the periods presented. However, portions of the net periodic benefit costs disclosed in the tables below have been capitalized as a component of property, plant and equipment. Amounts presented in the tables below for the Subsidiary Registrants represent the amounts of pension and other post-retirement benefit cost allocated by Duke Energy for employees of the Subsidiary Registrants. Additionally, the Subsidiary Registrants are allocated their proportionate share of pension and post-retirement benefit cost for employees of Duke Energy’s shared services affiliate that provide support to the Subsidiary Registrants. These allocated amounts are included in the governance and shared service costs discussed in Note 13 . Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. The following table includes information related to the Duke Energy Registrants’ contributions to its U.S. qualified defined benefit pension plans. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Anticipated Contributions: 2017 $ 160 $ 45 $ 45 $ 25 $ 20 $ 4 $ 9 Contributions Made: 2016 $ 155 $ 43 $ 43 $ 24 $ 20 $ 5 $ 9 2015 302 91 83 42 40 8 19 2014 — — — — — — — QUALIFIED PENSION PLANS Components of Net Periodic Pension Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 147 $ 48 $ 42 $ 24 $ 19 $ 4 $ 9 Interest cost on projected benefit obligation 335 86 106 49 55 19 28 Expected return on plan assets (519 ) (142 ) (168 ) (82 ) (84 ) (27 ) (42 ) Amortization of actuarial loss 134 33 51 23 29 4 11 Amortization of prior service credit (17 ) (8 ) (3 ) (2 ) (1 ) — (1 ) Settlement charge 3 — — — — — — Other 8 2 3 1 1 1 1 Net periodic pension costs (a)(b) $ 91 $ 19 $ 31 $ 13 $ 19 $ 1 $ 6 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 159 $ 50 $ 44 $ 23 $ 20 $ 4 $ 10 Interest cost on projected benefit obligation 324 83 104 48 54 18 27 Expected return on plan assets (516 ) (139 ) (171 ) (79 ) (87 ) (26 ) (42 ) Amortization of actuarial loss 166 39 65 33 31 7 13 Amortization of prior service (credit) cost (15 ) (7 ) (3 ) (2 ) (1 ) — 1 Other 8 2 3 1 1 — 1 Net periodic pension costs (a)(b) $ 126 $ 28 $ 42 $ 24 $ 18 $ 3 $ 10 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 135 $ 41 $ 40 $ 21 $ 20 $ 4 $ 9 Interest cost on projected benefit obligation 344 85 112 54 57 20 29 Expected return on plan assets (511 ) (132 ) (173 ) (85 ) (85 ) (27 ) (41 ) Amortization of actuarial loss 150 36 68 32 32 4 13 Amortization of prior service credit (15 ) (8 ) (3 ) (2 ) (1 ) — — Other 8 2 3 1 1 — 1 Net periodic pension costs (a)(b) $ 111 $ 24 $ 47 $ 21 $ 24 $ 1 $ 11 (a) Duke Energy amounts exclude $8 million , $9 million and $10 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $4 million , $4 million and $5 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase $ 214 $ 4 $ 34 $ 18 $ 16 $ 2 $ 9 Accumulated other comprehensive loss (income) Deferred income tax expense $ 4 — — — — — — Prior year service credit arising during the year (2 ) — — — — — — Amortization of prior year actuarial losses (7 ) — (1 ) — — — — Net amount recognized in accumulated other comprehensive income $ (5 ) $ — $ (1 ) $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 173 $ 65 $ 18 $ 14 $ 4 $ 14 $ 11 Accumulated other comprehensive (income) loss Deferred income tax expense $ 6 $ — $ 5 $ — $ — $ — $ — Actuarial losses arising during the year 4 — — — — — — Prior year service credit arising during the year 1 — — — — — — Amortization of prior year actuarial losses (11 ) — (4 ) — — — — Transfer with the Midwest Generation Disposal Group 3 — — — — — — Reclassification of actuarial losses to regulatory assets (6 ) — — — — — — Net amount recognized in accumulated other comprehensive income $ (3 ) $ — $ 1 $ — $ — $ — $ — Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 7,727 $ 1,995 $ 2,451 $ 1,143 $ 1,276 $ 453 $ 649 Obligation assumed from acquisition 352 — — — — — — Service cost 147 48 42 24 19 4 9 Interest cost 335 86 106 49 55 19 28 Actuarial loss 307 46 111 52 57 13 41 Transfers — 14 (3 ) (3 ) — (3 ) — Plan amendments (52 ) (3 ) — — — (3 ) (15 ) Benefits paid (679 ) (234 ) (195 ) (107 ) (84 ) (36 ) (54 ) Impact of settlements (6 ) — — — — — — Obligation at measurement date $ 8,131 $ 1,952 $ 2,512 $ 1,158 $ 1,323 $ 447 $ 658 Accumulated Benefit Obligation at measurement date $ 8,006 $ 1,952 $ 2,479 $ 1,158 $ 1,290 $ 436 $ 649 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,136 $ 2,243 $ 2,640 $ 1,284 $ 1,321 $ 433 $ 655 Assets received from acquisition 343 — — — — — — Employer contributions 155 43 43 24 20 5 9 Actual return on plan assets 582 159 190 92 95 29 47 Benefits paid (679 ) (234 ) (195 ) (107 ) (84 ) (36 ) (54 ) Impact of settlements (6 ) — — — — — — Transfers — 14 (3 ) (3 ) — (3 ) — Plan assets at measurement date $ 8,531 $ 2,225 $ 2,675 $ 1,290 $ 1,352 $ 428 $ 657 Funded status of plan $ 400 $ 273 $ 163 $ 132 $ 29 $ (19 ) $ (1 ) Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 8,107 $ 2,053 $ 2,557 $ 1,187 $ 1,335 $ 469 $ 673 Obligation transferred with Midwest Generation Disposal Group (83 ) — — — — — — Service cost 159 50 44 23 20 4 10 Interest cost 324 83 104 48 54 18 27 Actuarial gain (241 ) (53 ) (111 ) (46 ) (62 ) (9 ) (15 ) Transfers — 8 4 7 (3 ) 8 — Plan amendments (6 ) — — — — — (4 ) Benefits paid (533 ) (146 ) (147 ) (76 ) (68 ) (37 ) (42 ) Obligation at measurement date $ 7,727 $ 1,995 $ 2,451 $ 1,143 $ 1,276 $ 453 $ 649 Accumulated Benefit Obligation at measurement date $ 7,606 $ 1,993 $ 2,414 $ 1,143 $ 1,240 $ 442 $ 628 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,498 $ 2,300 $ 2,722 $ 1,321 $ 1,363 $ 456 $ 681 Obligation transferred with Midwest Generation Disposal Group (81 ) — — — — — — Employer contributions 302 91 83 42 40 8 19 Actual return on plan assets (50 ) (10 ) (22 ) (10 ) (11 ) (2 ) (3 ) Benefits paid (533 ) (146 ) (147 ) (76 ) (68 ) (37 ) (42 ) Transfers — 8 4 7 (3 ) 8 — Plan assets at measurement date $ 8,136 $ 2,243 $ 2,640 $ 1,284 $ 1,321 $ 433 $ 655 Funded status of plan $ 409 $ 248 $ 189 $ 141 $ 45 $ (20 ) $ 6 Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Prefunded pension (a) $ 518 $ 273 $ 225 $ 132 $ 91 $ 6 $ — Noncurrent pension liability (b) $ 118 $ — $ 62 $ — $ 62 $ 25 $ 1 Net asset recognized $ 400 $ 273 $ 163 $ 132 $ 29 $ (19 ) $ (1 ) Regulatory assets $ 2,098 $ 476 $ 805 $ 378 $ 426 $ 81 $ 171 Accumulated other comprehensive (income) loss Deferred income tax asset $ (41 ) $ — $ (6 ) $ — $ — $ — $ — Prior service credit (6 ) — — — — — — Net actuarial loss 123 — 16 — — — — Net amounts recognized in accumulated other comprehensive loss $ 76 $ — $ 10 $ — $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 147 $ 31 $ 52 $ 23 $ 29 $ 5 $ 8 Unrecognized prior service credit (24 ) (8 ) (3 ) (2 ) (1 ) — (2 ) December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Prefunded pension (a) $ 474 $ 252 $ 232 $ 145 $ 84 $ 1 $ 6 Noncurrent pension liability (b) $ 65 $ 4 $ 43 $ 4 $ 39 $ 21 $ — Net asset recognized $ 409 $ 248 $ 189 $ 141 $ 45 $ (20 ) $ 6 Regulatory assets $ 1,884 $ 472 $ 771 $ 360 $ 410 $ 79 $ 162 Accumulated other comprehensive (income) loss Deferred income tax asset $ (45 ) $ — $ (6 ) $ — $ — $ — $ — Prior service credit (4 ) — — — — — — Net actuarial loss 130 — 17 — — — — Net amounts recognized in accumulated other comprehensive loss (c) $ 81 $ — $ 11 $ — $ — $ — $ — (a) Included in Other within Investments and Other Assets on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. (c) Excludes accumulated other comprehensive income of $13 million as of December 31, 2015 , net of tax, associated with a Brazilian retirement plan. Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2016 Duke Duke Duke Progress Energy Energy (in millions) Energy Energy Florida Ohio Projected benefit obligation $ 1,299 $ 665 $ 665 $ 311 Accumulated benefit obligation 1,239 633 633 299 Fair value of plan assets 1,182 604 604 286 December 31, 2015 Duke Duke Duke Progress Energy Energy (in millions) Energy Energy Florida Ohio Projected benefit obligation $ 1,216 $ 611 $ 611 $ 307 Accumulated benefit obligation 1,158 575 575 298 Fair value of plan assets 1,151 574 574 289 Assumptions Used for Pension Benefits Accounting The discount rate used to determine the current year pension obligation and following year’s pension expense is based on a bond selection-settlement portfolio approach. This approach develops a discount rate by selecting a portfolio of high quality corporate bonds that generate sufficient cash flow to provide for projected benefit payments of the plan. The selected bond portfolio is derived from a universe of non-callable corporate bonds rated Aa quality or higher. After the bond portfolio is selected, a single interest rate is determined that equates the present value of the plan’s projected benefit payments discounted at this rate with the market value of the bonds selected. The average remaining service period of active covered employees is nine years for Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana. The following tables present the assumptions or range of assumptions used for pension benefit accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10% 4.40% 4.10% Salary increase 4.00 % - 4.50% 4.00 % - 4.40% 4.00 % - 4.40% Net Periodic Benefit Cost Discount rate 4.40% 4.10% 4.70% Salary increase 4.00 % - 4.40% 4.00 % - 4.40% 4.00 % - 4.40% Expected long-term rate of return on plan assets 6.50 % - 6.75% 6.50% 6.75% Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ending December 31, 2017 $ 585 $ 162 $ 159 $ 84 $ 74 $ 35 $ 49 2018 595 171 159 83 75 33 49 2019 613 177 164 86 76 33 48 2020 632 186 171 90 79 34 47 2021 637 181 175 92 81 35 48 2022 – 2026 3,099 867 890 455 425 161 219 NON-QUALIFIED PENSION PLANS Components of Net Periodic Pension Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 14 1 5 1 2 — — Amortization of actuarial loss 8 1 1 1 1 — — Amortization of prior service credit (1 ) — — — — — — Net periodic pension costs $ 23 $ 2 $ 6 $ 2 $ 3 $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ — $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 13 1 4 1 2 — — Amortization of actuarial loss 6 — 2 1 2 — 1 Amortization of prior service credit (1 ) — (1 ) — — — — Net periodic pension costs $ 21 $ 1 $ 6 $ 2 $ 4 $ — $ 1 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ — $ 1 $ 1 $ — $ — $ — Interest cost on projected benefit obligation 14 1 5 1 2 — — Amortization of actuarial loss 3 — 2 — — — — Amortization of prior service credit (1 ) — (1 ) — — — — Net periodic pension costs $ 19 $ 1 $ 7 $ 2 $ 2 $ — $ — Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net (decrease) increase $ (3 ) $ (2 ) $ 2 $ 1 $ 1 $ — $ (1 ) Regulatory liabilities, net increase (decrease) $ — $ — $ — $ — $ — $ — $ — Accumulated other comprehensive (income) loss Deferred income tax benefit $ — $ — $ — $ — $ — $ — $ — Prior service credit arising during the year (1 ) — — — — — — Actuarial loss arising during the year 1 — — — — — — Net amount recognized in accumulated other comprehensive loss (income) $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net (decrease) increase $ (13 ) $ 2 $ (16 ) $ (1 ) $ (15 ) $ — $ (1 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ (7 ) $ — $ (5 ) $ — $ — $ — $ — Amortization of prior service credit 1 — — — — — — Actuarial gains arising during the year 17 — 13 — — — — Net amount recognized in accumulated other comprehensive loss (income) $ 11 $ — $ 8 $ — $ — $ — $ — Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Obligation assumed from acquisition 5 — — — — — — Service cost 2 — — — — — — Interest cost 14 1 5 1 2 — — Actuarial losses (gains) 4 (1 ) 5 2 1 — (2 ) Plan amendments (2 ) — — — — — — Benefits paid (32 ) (2 ) (8 ) (3 ) (3 ) — — Obligation at measurement date $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Accumulated Benefit Obligation at measurement date $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Change in Fair Value of Plan Assets Benefits paid $ (32 ) $ (2 ) $ (8 ) $ (3 ) $ (3 ) $ — $ — Employer contributions 32 2 8 3 3 — — Plan assets at measurement date $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 337 $ 16 $ 116 $ 35 $ 61 $ 4 $ 5 Service cost 3 — 1 — — — — Interest cost 13 1 4 1 2 — — Actuarial losses (gains) 10 1 (1 ) — (14 ) — — Transfers 4 — — — — — — Benefits paid (26 ) (2 ) (8 ) (3 ) (3 ) — — Obligation at measurement date $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Accumulated Benefit Obligation at measurement date $ 336 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Change in Fair Value of Plan Assets Plan assets at prior measurement date — — — — — — — Benefits paid (26 ) (2 ) (8 ) (3 ) (3 ) — — Employer contributions 26 2 8 3 3 — — Plan assets at measurement date $ — $ — $ — $ — $ — $ — $ — Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current pension liability (a) $ 28 $ 2 $ 8 $ 2 $ 3 $ — $ — Noncurrent pension liability (b) 304 12 106 31 43 4 3 Total accrued pension liability $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Regulatory assets $ 73 $ 5 $ 18 $ 7 $ 11 $ 1 $ — Accumulated other comprehensive (income) loss Deferred income tax asset $ (3 ) $ — $ (3 ) $ — $ — $ — $ — Prior service credit (1 ) — — — — — — Net actuarial loss 10 — 9 — — — — Net amounts recognized in accumulated other comprehensive income $ 6 $ — $ 6 $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss $ 7 $ — $ 2 $ 1 $ 1 $ — $ — Unrecognized prior service credit (2 ) — — — — — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current pension liability (a) $ 27 $ 2 $ 8 $ 3 $ 3 $ — $ — Noncurrent pension liability (b) 314 14 104 30 43 4 5 Total accrued pension liability $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Regulatory assets $ 76 $ 7 $ 16 $ 6 $ 10 $ 1 $ 1 Accumulated other comprehensive (income) loss Deferred income tax asset $ (3 ) $ — $ (3 ) $ — $ — $ — $ — Net actuarial loss 9 — 9 — — — — Net amounts recognized in accumulated other comprehensive loss $ 6 $ — $ 6 $ — $ — $ — $ — (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Projected benefit obligation $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Accumulated benefit obligation 332 14 114 33 46 4 3 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Projected benefit obligation $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Accumulated benefit obligation 336 16 112 33 46 4 5 Assumptions Used for Pension Benefits Accounting The discount rate used to determine the current year pension obligation and following year’s pension expense is based on a bond selection-settlement portfolio approach. This approach develops a discount rate by selecting a portfolio of high quality corporate bonds that generate sufficient cash flow to provide for projected benefit payments of the plan. The selected bond portfolio is derived from a universe of non-callable corporate bonds rated Aa quality or higher. After the bond portfolio is selected, a single interest rate is determined that equates the present value of the plan’s projected benefit payments discounted at this rate with the market value of the bonds selected. The average remaining service period of active covered employees is 10 years for Duke Energy, seven years for Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, 14 years for Progress Energy, 12 years for Duke Energy Progress and 15 years for Duke Energy Florida. The following tables present the assumptions used for pension benefit accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10 % 4.40 % 4.10 % Salary increase 4.40 % 4.40 % 4.40 % Net Periodic Benefit Cost Discount rate 4.40 % 4.10 % 4.70 % Salary increase 4.40 % 4.40 % 4.40 % Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ending December 31, 2017 $ 29 $ 2 $ 8 $ 3 $ 3 $ — $ — 2018 25 2 8 3 3 — — 2019 25 2 8 2 3 — — 2020 24 2 8 2 3 — — 2021 24 1 8 2 3 — — 2021 - 2025 111 5 36 11 15 1 1 OTHER POST-RETIREMENT BENEFIT PLANS Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. The health care benefits include medical, dental and prescription drug coverage and are subject to certain limitations, such as deductibles and co-payments. Duke Energy did not make any pre-funding contributions to its other post-retirement benefit plans during the years ended December 31, 2016 , 2015 or 2014 . Components of Net Periodic Other Post-Retirement Benefit Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ 1 $ 1 $ — $ 1 $ — $ — Interest cost on accumulated post-retirement benefit obligation 35 8 15 8 7 1 4 Expected return on plan assets (12 ) (8 ) — — — — (1 ) Amortization of actuarial loss (gain) 6 (3 ) 22 13 9 (2 ) (1 ) Amortization of prior service credit (141 ) (14 ) (103 ) (68 ) (35 ) — (1 ) Net periodic post-retirement benefit costs (a)(b) $ (109 ) $ (16 ) $ (65 ) $ (47 ) $ (18 ) $ (1 ) $ 1 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 6 $ 1 $ 1 $ 1 $ 1 $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 36 9 15 8 7 2 4 Expected return on plan assets (13 ) (8 ) — — — (1 ) (1 ) Amortization of actuarial loss (gain) 16 (2 ) 28 18 10 (2 ) (2 ) Amortization of prior service credit (140 ) (14 ) (102 ) (68 ) (35 ) — — Net periodic post-retirement benefit costs (a)(b) $ (95 ) $ (14 ) $ (58 ) $ (41 ) $ (17 ) $ (1 ) $ 2 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 10 $ 2 $ 4 $ 1 $ 3 $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 49 12 22 11 12 2 5 Expected return on plan assets (13 ) (9 ) — — — — (1 ) Amortization of actuarial loss (gain) 39 3 42 31 10 (2 ) — Amortization of prior service credit (125 ) (11 ) (95 ) (73 ) (21 ) — — Net periodic post-retirement benefit costs (a)(b) $ (40 ) $ (3 ) $ (27 ) $ (30 ) $ 4 $ — $ 5 (a) Duke Energy amounts exclude $8 million , $10 million and $9 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $3 million and $2 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 53 $ — $ 47 $ 38 $ 9 $ — $ (6 ) Regulatory liabilities, net increase (decrease) $ (114 ) $ (22 ) $ (51 ) $ (25 ) $ (26 ) $ (2 ) $ (12 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ (2 ) $ — $ — $ — $ — $ — $ — Actuarial losses arising during the year 3 — — — — — — Amortization of prior year prior service credit 1 — 1 — — — — Net amount recognized in accumulated other comprehensive income $ 2 $ — $ 1 $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 1 $ — $ 1 $ — $ 1 $ — $ (7 ) Regulatory liabilities, net increase (decrease) $ (92 ) $ (8 ) $ (71 ) $ (36 ) $ (35 ) $ 2 $ (8 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ 2 $ — $ (1 ) $ — $ — $ — $ — Actuarial losses (gains) arising during the year (5 ) — 2 — — — — Transfer with the Midwest Generation Disposal Group (3 ) — — — — — — Amortization of prior year prior service credit 3 — (1 ) — — — — Net amount recognized in accumulated other comprehensive income $ (3 ) $ — $ — $ — $ — $ — $ — Reconciliation of Funded Status to Accrued Other Post-Retirement Benefit Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 828 $ 200 $ 354 $ 188 $ 164 $ 35 $ 87 Obligation assumed from acquisition 39 — — — — — — Service cost 3 1 1 — 1 — — Interest cost 35 8 15 8 7 1 4 Plan participants' contributions 19 3 7 4 3 1 2 Actuarial (gains) losses 33 5 16 8 8 — 3 Transfers — 1 — — — — — Plan amendments (1 ) — — — — (1 ) — Benefits paid (88 ) (17 ) (36 ) (17 ) (19 ) (4 ) (13 ) Accumulated post-retirement benefit obligation at measurement date $ 868 $ 201 $ 357 $ 191 $ 164 $ 32 $ 83 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 208 $ 134 $ — $ — $ 1 $ 8 $ 19 Assets received from acquisition 29 — — — — — — Actual return on plan assets 14 8 1 — — 1 2 Benefits paid (88 ) (17 ) (36 ) (17 ) (19 ) (4 ) (13 ) Employer contributions 62 9 29 13 15 1 12 Plan participants' contributions 19 3 7 4 3 1 2 Plan assets at measurement date $ 244 $ 137 $ 1 $ — $ — $ 7 $ 22 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 916 $ 220 $ 379 $ 207 $ 170 $ 39 $ 96 Service cost 6 1 1 1 1 — 1 Interest cost 36 9 15 8 7 2 4 Plan participants' contributions 20 4 7 4 3 1 2 Actuarial (gains) losses (39 ) (18 ) (1 ) (13 ) 11 (3 ) 1 Transfers — 2 — — — — — Plan amendments (9 ) — — — — (1 ) (4 ) Benefits paid (100 ) (18 ) (47 ) (19 ) (28 ) (3 ) (13 ) Obligations transferred with the Midwest Generation Disposal Group (3 ) — — — — — — Accrued retiree drug subsidy 1 — — — — — — Accumulated post-retirement benefit obligation at measurement date $ 828 $ 200 $ 354 $ 188 $ 164 $ 35 $ 87 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 227 $ 145 $ — $ (1 ) $ — $ 8 $ 23 Actual return on plan assets (1 ) (1 ) 1 1 1 — (1 ) Benefits paid (100 ) (18 ) (47 ) (19 ) (28 ) (3 ) (13 ) Employer contributions 62 4 39 15 25 2 8 Plan participants' contributions 20 4 7 4 3 1 2 Plan assets at measurement date $ 208 $ 134 $ — $ — $ 1 $ 8 $ 19 Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current post-retirement liability (a) $ 38 $ — $ 31 $ 17 $ 15 $ 2 $ — Noncurrent post-retirement liability (b) 586 64 325 174 149 23 63 Total accrued post-retirement liability $ 624 $ 64 $ 356 $ 191 $ 164 $ 25 $ 63 Regulatory assets $ 54 $ — $ 48 $ 38 $ 10 $ — $ 51 Regulatory liabilities $ 174 $ 46 $ — $ — $ — $ 19 $ 71 Accumulated other comprehensive (income) loss Deferred income tax liability $ 5 $ — $ — $ — $ — $ — $ — Prior service credit (5 ) — — — — — — Net actuarial gain (10 ) — — — — — — Net amounts recognized in accumulated other comprehensive income $ (10 ) $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss (gain) $ 10 $ (2 ) $ 21 $ 12 $ 9 $ (2 ) $ (6 ) Unrecognized prior service credit (115 ) (10 ) (85 ) (55 ) (30 ) — (1 ) December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current post-retirement liability (a) $ 37 $ — $ 31 $ 16 $ 15 $ 2 $ — Noncurrent post-retirement liability (b) 583 66 323 172 149 25 68 Total accrued post-retirement liability $ 620 $ 66 $ 354 $ 188 $ 164 $ 27 $ 68 Regulatory assets $ 1 $ — $ 1 $ — $ 1 $ — $ 57 Regulatory liabilities $ 288 $ 68 $ 51 $ 25 $ 26 $ 21 $ 83 Accumulated other comprehensive (income) loss Deferred income tax liability $ 7 $ — $ — $ — $ — $ — $ — Prior service credit (6 ) — (1 ) — — — — Net actuarial gain (13 ) — — — — — — Net amounts recognized in accumulated other comprehensive income $ (12 ) $ — $ (1 ) $ — $ — $ — $ — (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. Assumptions Used for Other Post-Retirement Benefits Accounting The discount rate used to determine the current year other post-retirement benefits obligation and following year’s other post-retirement benefits expense is based on a bond selection-settlement portfolio approach. This approach develops a discount rate by selecting a portfolio of high quality corporate bonds that generate sufficient cash flow to provide for projected benefit payments of the plan. The selected bond portfolio is derived from a universe of non-callable corporate bonds rated Aa quality or higher. After the bond portfolio is selected, a single interest rate is determined that equates the present value of the plan’s projected benefit payments discounted at this rate with the market value of the bonds selected. The average remaining service period of active covered employees is nine years for Duke Energy, 11 years for Duke Energy Carolinas, eight years for Duke Energy Ohio, nine years for Duke Energy Indiana and Duke Energy Kentucky, seven years for Progress Energy and Duke Energy Progress and eight years for Duke Energy Florida. The following tables present the assumptions used for other post-retirement benefits accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10 % 4.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income Tax Expense Components of Income Tax Expense Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 139 $ 15 $ (59 ) $ 76 $ (7 ) $ 7 State (15 ) 25 (19 ) (25 ) 22 (13 ) 6 Foreign 2 — — — — — — Total current income taxes (13 ) 164 (4 ) (84 ) 98 (20 ) 13 Deferred income taxes Federal 1,064 430 486 350 199 88 202 State 117 45 50 40 25 11 11 Total deferred income taxes (a) 1,181 475 536 390 224 99 213 Investment tax credit amortization (12 ) (5 ) (5 ) (5 ) — (1 ) (1 ) Income tax expense from continuing operations 1,156 634 527 301 322 78 225 Tax (benefit) expense from discontinued operations (30 ) — 1 — — (36 ) — Total income tax expense included in Consolidated Statements of Operations $ 1,126 $ 634 $ 528 $ 301 $ 322 $ 42 $ 225 (a) Includes benefits of net operating loss (NOL) carryforwards and tax credit carryforwards of $648 million at Duke Energy, $4 million at Duke Energy Carolinas, $190 million at Progress Energy, $60 million at Duke Energy Progress, $49 million at Duke Energy Florida, $26 million at Duke Energy Ohio and $58 million at Duke Energy Indiana. Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 216 $ (193 ) $ (56 ) $ 1 $ (18 ) $ (86 ) State (12 ) 14 1 (4 ) (7 ) (1 ) (12 ) Foreign 4 — — — — — — Total current income taxes (8 ) 230 (192 ) (60 ) (6 ) (19 ) (98 ) Deferred income taxes Federal 1,097 345 694 334 290 96 245 State 181 57 27 27 58 5 17 Total deferred income taxes (a) 1,278 402 721 361 348 101 262 Investment tax credit amortization (14 ) (5 ) (7 ) (7 ) — (1 ) (1 ) Income tax expense from continuing operations 1,256 627 522 294 342 81 163 Tax expense (benefit) from discontinued operations 89 — (1 ) — — 22 — Total income tax expense included in Consolidated Statements of Operations $ 1,345 $ 627 $ 521 $ 294 $ 342 $ 103 $ 163 (a) Includes benefits of NOL carryforwards and utilization of NOL and tax credit carryforwards of $264 million at Duke Energy, $15 million at Duke Energy Carolinas, $119 million at Progress Energy, $21 million at Duke Energy Progress, $84 million at Duke Energy Florida, $3 million at Duke Energy Ohio and $45 million at Duke Energy Indiana. Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 161 $ (466 ) $ (184 ) $ (53 ) $ (73 ) $ (112 ) State 56 51 (8 ) 14 1 3 1 Foreign 6 — — — — — — Total current income taxes 62 212 (474 ) (170 ) (52 ) (70 ) (111 ) Deferred income taxes Federal 1,144 407 938 436 350 113 294 State 35 (25 ) 84 25 52 1 15 Total deferred income taxes (a)(b) 1,179 382 1,022 461 402 114 309 Investment tax credit amortization (16 ) (6 ) (8 ) (6 ) (1 ) (1 ) (1 ) Income tax expense from continuing operations 1,225 588 540 285 349 43 197 Tax expense (benefit) from discontinued operations 149 — (4 ) — — (300 ) — Total income tax expense (benefit) included in Consolidated Statements of Operations $ 1,374 $ 588 $ 536 $ 285 $ 349 $ (257 ) $ 197 (a) There were no benefits of NOL carryforwards. (b) Includes utilization of NOL carryforwards of $1,544 million at Duke Energy, $345 million at Duke Energy Carolinas, $530 million at Progress Energy, $291 million at Duke Energy Progress, $64 million at Duke Energy Florida, $56 million at Duke Energy Ohio and $141 million at Duke Energy Indiana. Duke Energy Income from Continuing Operations before Income Taxes Years Ended December 31, (in millions) 2016 2015 2014 Domestic $ 3,689 $ 3,831 $ 3,637 Foreign 45 79 126 Income from continuing operations before income taxes $ 3,734 $ 3,910 $ 3,763 Taxes on Foreign Earnings During 2014, Duke Energy declared a taxable dividend of foreign earnings in the form of notes payable that was expected to result in the repatriation of approximately $2.7 billion of cash held, and expected to be generated, by International businesses over a period of up to eight years. As a result of the decision to repatriate cumulative historical undistributed foreign earnings, Duke Energy recorded U.S. income tax expense of approximately $373 million in 2014. As of December 31, 2014, Duke Energy's intention was to indefinitely reinvest any future undistributed foreign earnings. In February 2016, Duke Energy announced it had initiated a process to divest the International Disposal Group and, accordingly, no longer intended to indefinitely reinvest post-2014 undistributed foreign earnings. This change in the Company's intent, combined with the extension of bonus depreciation by Congress in late 2015, allowed Duke Energy to more efficiently utilize foreign tax credits and reduce U.S. deferred tax liabilities associated with the historical unremitted foreign earnings by approximately $95 million during the year ended December 31, 2016. Due to the classification of the International Disposal Group as discontinued operations beginning in the fourth quarter of 2016, income tax amounts related to the International Disposal Group's foreign earnings are presented within (Loss) Income from Discontinued Operations, net of tax on the Consolidated Statements of Operations. In December 2016, Duke Energy closed on the sale of the International Disposal Group in two separate transactions to execute the divestiture. See Note 2 for additional information on the sale. Statutory Rate Reconciliation The following tables present a reconciliation of income tax expense at the U.S. federal statutory tax rate to the actual tax expense from continuing operations. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,307 $ 630 $ 548 $ 315 $ 306 $ 95 $ 212 State income tax, net of federal income tax effect 64 46 20 10 30 (2 ) 11 AFUDC equity income (70 ) (36 ) (26 ) (17 ) (9 ) (2 ) (6 ) Renewable energy production tax credits (97 ) — — — — — — Audit adjustment 5 3 — — — — — Tax true-up (14 ) (14 ) (11 ) (3 ) (9 ) (16 ) 2 Other items, net (39 ) 5 (4 ) (4 ) 4 3 6 Income tax expense from continuing operations $ 1,156 $ 634 $ 527 $ 301 $ 322 $ 78 $ 225 Effective tax rate 31.0 % 35.2 % 33.7 % 33.4 % 36.9 % 28.9 % 37.1 % Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,369 $ 598 $ 555 $ 302 $ 330 $ 81 $ 168 State income tax, net of federal income tax effect 109 46 18 15 33 2 2 AFUDC equity income (58 ) (34 ) (19 ) (17 ) (3 ) (1 ) (4 ) Renewable energy production tax credits (72 ) — (1 ) — — — — Audit adjustment (22 ) — (23 ) 1 (24 ) — — Tax true-up 2 2 (3 ) (4 ) 2 (5 ) (9 ) Other items, net (72 ) 15 (5 ) (3 ) 4 4 6 Income tax expense from continuing operations $ 1,256 $ 627 $ 522 $ 294 $ 342 $ 81 $ 163 Effective tax rate 32.1 % 36.7 % 32.9 % 34.2 % 36.3 % 35.2 % 34.0 % Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,317 $ 581 $ 497 $ 263 $ 314 $ 39 $ 195 State income tax, net of federal income tax effect 59 17 49 25 34 3 10 AFUDC equity income (47 ) (32 ) (9 ) (9 ) — (1 ) (5 ) Renewable energy production tax credits (67 ) — — — — — — Other items, net (37 ) 22 3 6 1 2 (3 ) Income tax expense from continuing operations $ 1,225 $ 588 $ 540 $ 285 $ 349 $ 43 $ 197 Effective tax rate 32.6 % 35.4 % 38.0 % 37.9 % 38.9 % 38.9 % 35.5 % Valuation allowances have been established for certain state NOL carryforwards and state income tax credits that reduce deferred tax assets to an amount that will be realized on a more-likely-than-not basis. The net change in the total valuation allowance is included in the State income tax, net of federal income tax effect in the above tables. DEFERRED TAXES Net Deferred Income Tax Liability Components December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Deferred credits and other liabilities $ 382 $ 66 $ 126 $ 40 $ 93 $ 21 $ 4 Capital lease obligations 60 8 — — — — 1 Pension, post-retirement and other employee benefits 561 16 199 91 96 22 37 Progress Energy merger purchase accounting adjustments (a) 918 — — — — — — Tax credits and NOL carryforwards 4,682 192 1,165 222 232 49 278 Investments and other assets — — — — — 3 — Other 205 16 35 8 — 5 9 Valuation allowance (96 ) — (12 ) — — — — Total deferred income tax assets 6,712 298 1,513 361 421 100 329 Investments and other assets (1,892 ) (1,149 ) (597 ) (313 ) (297 ) — (21 ) Accelerated depreciation rates (14,872 ) (4,664 ) (4,490 ) (2,479 ) (2,038 ) (1,404 ) (1,938 ) Regulatory assets and deferred debits, net (4,103 ) (1,029 ) (1,672 ) (892 ) (780 ) (139 ) (270 ) Total deferred income tax liabilities (20,867 ) (6,842 ) (6,759 ) (3,684 ) (3,115 ) (1,543 ) (2,229 ) Net deferred income tax liabilities $ (14,155 ) $ (6,544 ) $ (5,246 ) $ (3,323 ) $ (2,694 ) $ (1,443 ) $ (1,900 ) (a) Primarily related to capital lease obligations and debt fair value adjustments. The following table presents the expiration of tax credits and NOL carryforwards. December 31, 2016 (in millions) Amount Expiration Year Investment tax credits $ 1,143 2027 — 2036 Alternative minimum tax credits 1,151 Indefinite Federal NOL carryforwards 1,267 2020 — 2036 State NOL carryforwards and credits (a) 248 2017 — 2036 Foreign NOL carryforwards (b) 12 2026 — 2036 Foreign Tax Credits 859 2024 — 2026 Charitable Carryforwards 2 2017 — 2019 Total tax credits and NOL carryforwards $ 4,682 (a) A valuation allowance of $84 million has been recorded on the state NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (b) A valuation allowance of $12 million has been recorded on the foreign NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Deferred credits and other liabilities $ 201 $ 38 $ 115 $ 25 $ 66 $ 29 $ 5 Capital lease obligations 63 9 — — — — 2 Pension, post-retirement and other employee benefits 580 46 186 92 82 24 40 Progress Energy merger purchase accounting adjustments (a) 1,009 — — — — — — Tax credits and NOL carryforwards 3,631 170 997 163 177 25 215 Investments and other assets — — — — — 3 — Other 206 20 48 2 46 37 20 Valuation allowance (93 ) — (38 ) — — — — Total deferred income tax assets 5,597 283 1,308 282 371 118 282 Investments and other assets (1,573 ) (1,057 ) (412 ) (228 ) (201 ) — (7 ) Accelerated depreciation rates (12,939 ) (4,429 ) (4,169 ) (2,325 ) (1,868 ) (1,356 ) (1,797 ) Regulatory assets and deferred debits, net (3,633 ) (943 ) (1,517 ) (756 ) (762 ) (169 ) (135 ) Total deferred income tax liabilities (18,145 ) (6,429 ) (6,098 ) (3,309 ) (2,831 ) (1,525 ) (1,939 ) Net deferred income tax liabilities $ (12,548 ) $ (6,146 ) $ (4,790 ) $ (3,027 ) $ (2,460 ) $ (1,407 ) $ (1,657 ) (a) Primarily related to capital lease obligations and debt fair value adjustments. On August 6, 2015, pursuant to N.C. Gen. Stat. 105-130.3C, the North Carolina Department of Revenue announced the North Carolina corporate income tax rate would be reduced from a statutory rate of 5.0 percent to 4.0 percent beginning January 1, 2016. Duke Energy recorded a net reduction of approximately $95 million to its North Carolina deferred tax liability in the third quarter of 2015. The significant majority of this deferred tax liability reduction was offset by recording a regulatory liability pending NCUC determination of the disposition of amounts related to Duke Energy Carolinas and Duke Energy Progress. The impact did not have a significant impact on the financial position, results of operation, or cash flows of Duke Energy, Duke Energy Carolinas, Progress Energy or Duke Energy Progress. On August 4, 2016, pursuant to N.C. Gen. Stat. 105-130.3C, the North Carolina Department of Revenue announced the North Carolina corporate income tax rate would be reduced from a statutory rate of 4.0 percent to 3.0 percent beginning January 1, 2017. Duke Energy recorded a net reduction of approximately $80 million to its North Carolina deferred tax liability in the third quarter of 2016. The significant majority of this deferred tax liability reduction was offset by recording a regulatory liability pending NCUC determination of the disposition of amounts related to Duke Energy Carolinas and Duke Energy Progress. The impact did not have a significant impact on the financial position, results of operation, or cash flows of Duke Energy, Duke Energy Carolinas, Progress Energy or Duke Energy Progress. UNRECOGNIZED TAX BENEFITS The following tables present changes to unrecognized tax benefits. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Ohio Indiana Unrecognized tax benefits – January 1 $ 88 $ 72 $ 1 $ 3 $ — $ 1 Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods — — — — 4 — Gross decreases – tax positions in prior periods (4 ) (4 ) (1 ) (1 ) — — Decreases due to settlements (68 ) (67 ) — — — (1 ) Reduction due to lapse of statute of limitations 1 — 2 — — — Total changes (71 ) (71 ) 1 (1 ) 4 (1 ) Unrecognized tax benefits – December 31 $ 17 $ 1 $ 2 $ 2 $ 4 $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Unrecognized tax benefits – January 1 $ 213 $ 160 $ 32 $ 23 $ 8 $ 1 Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods — — 1 1 — — Gross decreases – tax positions in prior periods (48 ) (45 ) — — — — Decreases due to settlements (45 ) (43 ) — — — — Reduction due to lapse of statute of limitations (32 ) — (32 ) (21 ) (8 ) — Total changes (125 ) (88 ) (31 ) (20 ) (8 ) — Unrecognized tax benefits – December 31 $ 88 $ 72 $ 1 $ 3 $ — $ 1 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Unrecognized tax benefits – January 1 $ 230 $ 171 $ 32 $ 22 $ 8 $ 1 Unrecognized tax benefits increases (decreases) Gross increases — tax positions in prior periods — — 1 1 — — Gross decreases – tax positions in prior periods (2 ) — — — — — Decreases due to settlements (15 ) (11 ) (1 ) — — — Total changes (17 ) (11 ) — 1 — — Unrecognized tax benefits – December 31 $ 213 $ 160 $ 32 $ 23 $ 8 $ 1 The following table includes additional information regarding the Duke Energy Registrants' unrecognized tax benefits. It is reasonably possible that Duke Energy could reflect an approximate $8 million reduction and Duke Energy Carolinas could reflect an approximate $1 million reduction in unrecognized tax benefits within the next 12 months. All other Duke Energy Registrants do not anticipate a material increase or decrease in unrecognized tax benefits within the next 12 months. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Amount that if recognized, would affect the effective tax rate or regulatory liability (a) $ 8 $ 1 $ 2 $ 2 $ — $ — $ — Amount that if recognized, would be recorded as a component of discontinued operations 5 — — — — 2 — (a) Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana are unable to estimate the specific amounts that would affect the effective tax rate versus the regulatory liability. OTHER TAX MATTERS The following tables include interest recognized in the Consolidated Statements of Operations and the Consolidated Balance Sheets. Year Ended December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Net interest income recognized related to income taxes $ — $ — $ 1 $ — $ 2 Net interest expense recognized related to income taxes — 7 — — — Interest payable related to income taxes 4 23 1 1 — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Net interest income recognized related to income taxes $ 12 $ — $ 2 $ 2 $ 1 $ 1 Net interest expense recognized related to income taxes — 1 — — — — Interest receivable related to income taxes 3 — — — — 3 Interest payable related to income taxes — 14 — 1 — — Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Net interest income recognized related to income taxes $ 6 $ — $ 3 $ — $ 1 $ 4 $ 4 Net interest expense recognized related to income taxes — 1 — 1 — — — Interest receivable related to income taxes — — — — — — 2 Interest payable related to income taxes 13 13 5 3 5 — — Duke Energy and its subsidiaries are no longer subject to U.S. federal examination for years before 2015. With few exceptions, Duke Energy and its subsidiaries are no longer subject to state, local or non-U.S. income tax examinations by tax authorities for years before 2004.

Other Income and Expenses, Net

Other Income and Expenses, Net	12 Months Ended
	Dec. 31, 2016
Other Income and Expenses [Abstract]
Other Income and Expenses, Net	OTHER INCOME AND EXPENSES, NET The components of Other income and expenses, net on the Consolidated Statements of Operations are as follows. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 21 $ 4 $ 4 $ 3 $ 2 $ 5 $ 6 AFUDC equity 200 102 76 50 26 6 16 Post in-service equity returns 67 55 12 12 — — — Nonoperating income (expense), other 36 1 22 6 16 (2 ) — Other income and expense, net $ 324 $ 162 $ 114 $ 71 $ 44 $ 9 $ 22 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 20 $ 2 $ 4 $ 2 $ 2 $ 4 $ 6 AFUDC equity 164 96 54 47 7 3 11 Post in-service equity returns 73 60 13 13 — — — Nonoperating income (expense), other 33 2 26 9 15 (1 ) (6 ) Other income and expense, net $ 290 $ 160 $ 97 $ 71 $ 24 $ 6 $ 11 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 16 $ 4 $ 3 $ — $ 2 $ 8 $ 6 AFUDC equity 135 91 26 25 — 4 14 Post in-service equity returns 89 71 17 17 — — — Nonoperating income (expense), other 80 6 31 9 18 (2 ) 2 Other income and expense, net $ 320 $ 172 $ 77 $ 51 $ 20 $ 10 $ 22

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to regulatory matters, commitments and contingencies, and debt and credit facilities see Notes 4, 5 and 6, respectively.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	QUARTERLY FINANCIAL DATA (UNAUDITED) DUKE ENERGY Quarterly EPS amounts may not sum to the full-year total due to changes in the weighted average number of common shares outstanding and rounding. First Second Third Fourth (in millions, except per share data) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 5,377 $ 5,213 $ 6,576 $ 5,577 $ 22,743 Operating income 1,240 1,259 1,954 888 5,341 Income from continuing operations 577 624 1,001 376 2,578 Income (loss) from discontinued operations, net of tax 122 (112 ) 180 (598 ) (408 ) Net income (loss) 699 512 1,181 (222 ) 2,170 Net income (loss) attributable to Duke Energy Corporation 694 509 1,176 (227 ) 2,152 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic $ 0.83 $ 0.90 $ 1.44 $ 0.53 $ 3.71 Diluted $ 0.83 $ 0.90 $ 1.44 $ 0.53 $ 3.71 Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders Basic $ 0.18 $ (0.16 ) $ 0.26 $ (0.86 ) $ (0.60 ) Diluted $ 0.18 $ (0.16 ) $ 0.26 $ (0.86 ) $ (0.60 ) Net income (loss) attributable to Duke Energy Corporation common stockholders Basic $ 1.01 $ 0.74 $ 1.70 $ (0.33 ) $ 3.11 Diluted $ 1.01 $ 0.74 $ 1.70 $ (0.33 ) $ 3.11 2015 Operating revenues $ 5,792 $ 5,302 $ 6,202 $ 5,075 $ 22,371 Operating income 1,390 1,192 1,606 890 5,078 Income from continuing operations 755 576 890 433 2,654 Income (Loss) from discontinued operations, net of tax 112 (29 ) 45 49 177 Net income 867 547 935 482 2,831 Net income attributable to Duke Energy Corporation 864 543 932 477 2,816 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic $ 1.06 $ 0.83 $ 1.29 $ 0.62 $ 3.80 Diluted $ 1.06 $ 0.83 $ 1.29 $ 0.62 $ 3.80 Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders Basic $ 0.16 $ (0.05 ) $ 0.06 $ 0.07 $ 0.25 Diluted $ 0.16 $ (0.05 ) $ 0.06 $ 0.07 $ 0.25 Net income attributable to Duke Energy Corporation common stockholders Basic $ 1.22 $ 0.78 $ 1.35 $ 0.69 $ 4.05 Diluted $ 1.22 $ 0.78 $ 1.35 $ 0.69 $ 4.05 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers (see Note 2) $ (120 ) $ (111 ) $ (84 ) $ (208 ) $ (523 ) Commercial Renewables Impairment (see Note 12) — — (71 ) — (71 ) Loss on Sale of International Disposal Group (see Note 2) — — — (514 ) (514 ) Impairment of Assets in Central America (see Note 2) — (194 ) — — (194 ) Cost Savings Initiatives (see Note 19) (20 ) (24 ) (19 ) (29 ) (92 ) Total $ (140 ) $ (329 ) $ (174 ) $ (751 ) $ (1,394 ) 2015 Costs to Achieve Mergers $ (21 ) $ (22 ) $ (24 ) $ (30 ) $ (97 ) Edwardsport Settlement (see Note 4) — — (90 ) (3 ) (93 ) Ash Basin Settlement and Penalties (see Note 5) — — (7 ) (7 ) (14 ) State Tax Adjustment related to Midwest Generation Sale — (41 ) — — (41 ) Cost Savings Initiatives (see Note 19) — — — (142 ) (142 ) Total $ (21 ) $ (63 ) $ (121 ) $ (182 ) $ (387 ) DUKE ENERGY CAROLINAS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,740 $ 1,675 $ 2,226 $ 1,681 $ 7,322 Operating income 481 464 815 302 2,062 Net income 271 261 494 140 1,166 2015 Operating revenues $ 1,901 $ 1,707 $ 2,061 $ 1,560 $ 7,229 Operating income 515 483 666 296 1,960 Net income 292 265 383 141 1,081 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (11 ) $ (12 ) $ (13 ) $ (68 ) $ (104 ) Cost Savings Initiatives (see Note 19) (10 ) (10 ) (8 ) (11 ) (39 ) Total $ (21 ) $ (22 ) $ (21 ) $ (79 ) $ (143 ) 2015 Costs to Achieve Mergers $ (9 ) $ (11 ) $ (11 ) $ (16 ) $ (47 ) Ash Basin Settlement and Penalties (see Note 5) — — (1 ) (7 ) (8 ) Cost Savings Initiatives (see Note 19) — — — (93 ) (93 ) Total $ (9 ) $ (11 ) $ (12 ) $ (116 ) $ (148 ) PROGRESS ENERGY First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 2,332 $ 2,348 $ 2,965 $ 2,208 $ 9,853 Operating income 475 560 814 292 2,141 Income from continuing operations 212 274 449 104 1,039 Net income 212 274 449 106 1,041 Net income attributable to Parent 209 272 446 104 1,031 2015 Operating revenues $ 2,536 $ 2,476 $ 2,929 $ 2,336 $ 10,277 Operating income 549 504 756 351 2,160 Income from continuing operations 264 217 452 132 1,065 Net income 263 217 451 131 1,062 Net income attributable to Parent 260 215 448 128 1,051 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (7 ) $ (8 ) $ (10 ) $ (44 ) $ (69 ) Cost Savings Initiatives (see Note 19) (8 ) (8 ) (10 ) (14 ) (40 ) Total $ (15 ) $ (16 ) $ (20 ) $ (58 ) $ (109 ) 2015 Costs to Achieve Mergers $ (8 ) $ (8 ) $ (8 ) $ (10 ) $ (34 ) Ash Basin Settlement and Penalties (see Note 5) — — (6 ) — (6 ) Cost Savings Initiatives (see Note 19) — — — (36 ) (36 ) Total $ (8 ) $ (8 ) $ (14 ) $ (46 ) $ (76 ) DUKE ENERGY PROGRESS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,307 $ 1,213 $ 1,583 $ 1,174 $ 5,277 Operating income 258 255 438 135 1,086 Net income 137 131 271 60 599 2015 Operating revenues $ 1,449 $ 1,193 $ 1,488 $ 1,160 $ 5,290 Operating income 316 184 394 130 1,024 Net income 183 85 229 69 566 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (5 ) $ (5 ) $ (6 ) $ (40 ) $ (56 ) Cost Savings Initiatives (see Note 19) (5 ) (5 ) (7 ) (6 ) (23 ) Total $ (10 ) $ (10 ) $ (13 ) $ (46 ) $ (79 ) 2015 Costs to Achieve Mergers $ (5 ) $ (5 ) $ (6 ) $ (6 ) $ (22 ) Ash Basin Settlement and Penalties (see Note 5) — — (6 ) — (6 ) Cost Savings Initiatives (see Note 19) — — — (28 ) (28 ) Total $ (5 ) $ (5 ) $ (12 ) $ (34 ) $ (56 ) DUKE ENERGY FLORIDA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,024 $ 1,133 $ 1,381 $ 1,030 $ 4,568 Operating income 213 300 373 155 1,041 Net income 110 171 206 64 551 2015 Operating revenues $ 1,086 $ 1,281 $ 1,436 $ 1,174 $ 4,977 Operating income 227 315 357 216 1,115 Net income 113 165 216 105 599 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (2 ) $ (3 ) $ (4 ) $ (4 ) $ (13 ) Cost Savings Initiatives (see Note 19) (2 ) (3 ) (3 ) (9 ) (17 ) Total $ (4 ) $ (6 ) $ (7 ) $ (13 ) $ (30 ) 2015 Costs to Achieve Mergers $ (3 ) $ (3 ) $ (3 ) $ (4 ) $ (13 ) Cost Savings Initiatives (see Note 19) — — — (8 ) (8 ) Total $ (3 ) $ (3 ) $ (3 ) $ (12 ) $ (21 ) DUKE ENERGY OHIO First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 516 $ 428 $ 489 $ 511 $ 1,944 Operating income 96 55 106 90 347 Income from discontinued operations, net of tax 2 — 34 — 36 Net income 59 23 89 57 228 2015 Operating revenues $ 586 $ 405 $ 462 $ 452 $ 1,905 Operating income 111 43 76 73 303 Income (Loss) from discontinued operations, net of tax 90 (65 ) (2 ) — 23 Net income (loss) 149 (52 ) 32 43 172 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (1 ) $ (1 ) $ (2 ) $ (2 ) $ (6 ) Cost Savings Initiatives (see Note 19) (1 ) (1 ) — (1 ) (3 ) Total $ (2 ) $ (2 ) $ (2 ) $ (3 ) $ (9 ) 2015 Costs to Achieve Mergers $ (1 ) $ (1 ) $ (1 ) $ (1 ) $ (4 ) Cost Savings Initiatives (see Note 19) — — — (2 ) (2 ) Total $ (1 ) $ (1 ) $ (1 ) $ (3 ) $ (6 ) DUKE ENERGY INDIANA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 714 $ 702 $ 809 $ 733 $ 2,958 Operating income 176 174 239 176 765 Net income 95 85 129 72 381 2015 Operating revenues $ 788 $ 686 $ 749 $ 667 $ 2,890 Operating income 210 146 117 171 644 Net income 108 68 46 94 316 The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (1 ) $ (2 ) $ (3 ) $ (3 ) $ (9 ) Cost Savings Initiatives (see Note 19) (1 ) (4 ) (1 ) (1 ) (7 ) Total $ (2 ) $ (6 ) $ (4 ) $ (4 ) $ (16 ) 2015 Costs to Achieve Mergers $ (2 ) $ (1 ) $ (2 ) $ (2 ) $ (7 ) Edwardsport Settlement (see Note 4) — — (90 ) (3 ) (93 ) Cost Savings Initiatives (see Note 19) — — — (6 ) (6 ) Total $ (2 ) $ (1 ) $ (92 ) $ (11 ) $ (106 )

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2016
Policy Text Block [Line Items]
Nature of Operations and Basis of Consolidation	Nature of Operations and Basis of Consolidation Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) primarily through its direct and indirect subsidiaries. Certain Duke Energy subsidiaries are also subsidiary registrants, including Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, LLC (Duke Energy Progress); Duke Energy Florida, LLC (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio); and Duke Energy Indiana, LLC (Duke Energy Indiana). On October 3, 2016, Duke Energy acquired Piedmont Natural Gas Company, Inc. (Piedmont) which also became a wholly owned subsidiary and subsidiary registrant of Duke Energy. Duke Energy's consolidated financial statements include Piedmont's results of operations and cash flow activity subsequent to the acquisition. See Note 2 for additional information regarding the acquisition. When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its seven separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants). In October 2016, Duke Energy completed the acquisition of Piedmont, an energy services company whose principal business is the distribution of natural gas, for a total cash purchase price of $5.0 billion . The acquisition provides a foundation for establishing a broader strategic natural gas infrastructure platform within Duke Energy to complement the existing natural gas pipeline investments and the natural gas business located in the Midwest. For additional information on the details of this transaction including purchase price allocation and acquisition financing, see Note 2 . Piedmont continues to maintain reporting requirements as a Securities and Exchange Commission (SEC) registrant. In December 2016, Duke Energy completed an exit of the Latin American market to focus on its domestic regulated business, which was further bolstered by the acquisition of Piedmont. The sale of the International Energy business segment, excluding an equity method investment in National Methanol Company (NMC), was completed through two transactions including a sale of assets in Brazil to China Three Gorges (Luxembourg) Energy S.à.r.l. (CTG) and a sale of Duke Energy's remaining Latin American assets in Peru, Chile, Ecuador, Guatemala, El Salvador and Argentina to ISQ Enerlam Aggregator, L.P. and Enerlam (UK) Holding Ltd. (I Squared) (collectively, the International Disposal Group). For additional information on the sale of International Energy see Note 2 . The information in these combined notes relates to each of the Duke Energy Registrants, excluding Piedmont, as noted in the Index to Combined Notes to Consolidated Financial Statements. However, none of the registrants make any representation as to information related solely to Duke Energy or the Subsidiary Registrants of Duke Energy other than itself. These Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), Public Service Commission of South Carolina (PSCSC), U.S. Nuclear Regulatory Commission (NRC) and FERC. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting. Progress Energy is a public utility holding company headquartered in Raleigh, North Carolina, subject to regulation by the FERC. Progress Energy conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Substantially all of Progress Energy’s operations qualify for regulatory accounting. Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the Florida Public Service Commission (FPSC), NRC and FERC. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio also conducts competitive auctions for retail electricity supply in Ohio whereby recovery of the energy price is from retail customers and recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). For further information about the sale of the Midwest Generation business, refer to Note 2 "Acquisitions and Dispositions." Substantially all of Duke Energy Ohio's operations that remain after the sale qualify for regulatory accounting. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and FERC. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company. Piedmont is a regulated public utility primarily engaged in the distribution of natural gas in portions of North Carolina, South Carolina and Tennessee. Piedmont is invested in joint venture businesses including regulated interstate natural gas transportation and storage and intrastate natural gas transportation businesses. Piedmont is subject to the regulatory provisions of the NCUC, PSCSC, Tennessee Regulatory Authority (TRA) and FERC. Substantially all of Piedmont's operations qualify for regulatory accounting. Certain prior year amounts have been reclassified to conform to the current year presentation.
Discontinued Operations	Discontinued Operations The results of operations of the International Disposal Group and Duke Energy Ohio's nonregulated Midwest Generation business and Duke Energy Retail Sales, LLC (collectively, Midwest Generation Disposal Group) have been classified as Discontinued Operations on Duke Energy's Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these consolidated financial statements exclude amounts related to discontinued operations for all periods presented and assets held for sale (AHFS) and liabilities associated with AHFS as of December 31, 2015. See Note 2 for additional information.
Use of Estimates	Use of Estimates In preparing financial statements that conform to generally accepted accounting principles (GAAP) in the U.S., the Duke Energy Registrants must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Regulatory Accounting	Regulatory Accounting The majority of the Duke Energy Registrants’ operations are subject to price regulation for the sale of electricity and natural gas by state utility commissions or FERC. When prices are set on the basis of specific costs of the regulated operations and an effective franchise is in place such that sufficient natural gas or electric services can be sold to recover those costs, the Duke Energy Registrants apply regulatory accounting. Regulatory accounting changes the timing of the recognition of costs or revenues relative to a company that does not apply regulatory accounting. As a result, Regulatory assets and Regulatory liabilities are recognized on the Consolidated Balance Sheets. Regulatory assets and liabilities are amortized consistent with the treatment of the related cost in the ratemaking process. See Note 4 for further information. Regulatory accounting rules also require recognition of a disallowance (also called "impairment") loss if it becomes probable that part of the cost of a plant under construction (or a recently completed plant or an abandoned plant) will be disallowed for ratemaking purposes and a reasonable estimate of the amount of the disallowance can be made. Other disallowances can require judgments on allowed future rate recovery. When it becomes probable that regulated generation, transmission or distribution assets will be abandoned, the cost of the asset is removed from plant in service. The value that may be retained as a regulatory asset on the balance sheet for the abandoned property is dependent upon amounts that may be recovered through regulated rates, including any return. As such, an impairment charge could be partially or fully offset by the establishment of a regulatory asset if rate recovery is probable. The impairment for a disallowance of costs for regulated plants under construction, recently completed or abandoned is based on discounted cash flows.
Regulated Fuel Costs and Purchased Power	Regulated Fuel and Purchased Gas Adjustment Clauses The Duke Energy Registrants utilize cost-tracking mechanisms, commonly referred to as fuel adjustment clauses or purchased gas adjustment clauses (PGA). These clauses allow for the recovery of fuel and fuel-related costs, portions of purchased power, natural gas costs and hedging costs through surcharges on customer rates. The difference between the costs incurred and the surcharge revenues is recorded either as an adjustment to Operating Revenues, Operating Expenses – Fuel used in electric generation or Operating Expenses – Cost of natural gas on the Consolidated Statements of Operations, with an off-setting impact on regulatory assets or liabilities
Cash and Cash Equivalents	Cash and Cash Equivalents All highly liquid investments with maturities of three months or less at the date of acquisition are considered cash equivalents.
Restricted Cash	Restricted Cash The Duke Energy Registrants have restricted cash related primarily to collateral assets, escrow deposits and variable interest entities (VIEs). Restricted cash balances are reflected in Other within Current Assets and in Other within Investments and Other Assets on the Consolidated Balance Sheets. At December 31, 2016 and 2015 , Duke Energy had restricted cash totaling $137 million and $98 million , respectively.
Inventory	Inventory Inventory is used for operations and is recorded primarily using the average cost method. Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Materials and supplies are recorded as inventory when purchased and subsequently charged to expense or capitalized to property, plant and equipment when installed. Reserves are established for excess and obsolete inventory. Inventory reserves were not material at December 31, 2016 and 2015 . The components of inventory are presented in the tables below.
Investments in Debt and Equity Securities	Investments in Debt and Equity Securities The Duke Energy Registrants classify investments into two categories – trading and available-for-sale. Both categories are recorded at fair value on the Consolidated Balance Sheets. Realized and unrealized gains and losses on trading securities are included in earnings. For certain investments of regulated operations, such as the Nuclear Decommissioning Trust Fund (NDTF), realized and unrealized gains and losses (including any other-than-temporary impairments (OTTIs)) on available-for-sale securities are recorded as a regulatory asset or liability. Otherwise, unrealized gains and losses are included in Accumulated Other Comprehensive Income (AOCI), unless other-than-temporarily impaired. OTTIs for equity securities and the credit loss portion of debt securities of nonregulated operations are included in earnings. Investments in debt and equity securities are classified as either current or noncurrent based on management’s intent and ability to sell these securities, taking into consideration current market liquidity. See Note 15 for further information.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Duke Energy, Progress Energy and Duke Energy Ohio perform annual goodwill impairment tests as of August 31 each year at the reporting unit level, which is determined to be an operating segment or one level below. Duke Energy, Progress Energy and Duke Energy Ohio update these tests between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. Intangible Assets Intangible assets are included in Other in Investments and Other Assets on the Consolidated Balance Sheets. Generally, intangible assets are amortized using an amortization method that reflects the pattern in which the economic benefits of the intangible asset are consumed or on a straight-line basis if that pattern is not readily determinable. Amortization of intangibles is reflected in Depreciation and amortization on the Consolidated Statements of Operations. Intangible assets are subject to impairment testing and if impaired, the carrying value is accordingly reduced. Emission allowances permit the holder of the allowance to emit certain gaseous byproducts of fossil fuel combustion, including sulfur dioxide (SO 2 ) and nitrogen oxide. Allowances are issued by the U.S. Environmental Protection Agency (EPA) at zero cost and may also be bought and sold via third-party transactions. Allowances allocated to or acquired by the Duke Energy Registrants are held primarily for consumption. Carrying amounts for emission allowances are based on the cost to acquire the allowances or, in the case of a business combination, on the fair value assigned in the allocation of the purchase price of the acquired business. Emission allowances are expensed to Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Renewable energy certificates are used to measure compliance with renewable energy standards and are held primarily for consumption. See Note 11 for further information.
Long-Lived Asset Impairments	Long-Lived Asset Impairments The Duke Energy Registrants evaluate long-lived assets, excluding goodwill, for impairment when circumstances indicate the carrying value of those assets may not be recoverable. An impairment exists when a long-lived asset’s carrying value exceeds the estimated undiscounted cash flows expected to result from the use and eventual disposition of the asset. The estimated cash flows may be based on alternative expected outcomes that are probability weighted. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, the carrying value of the asset is written-down to its then-current estimated fair value and an impairment charge is recognized. The Duke Energy Registrants assess fair value of long-lived assets using various methods, including recent comparable third-party sales, internally developed discounted cash flow analysis and analysis from outside advisors. Significant changes in commodity prices, the condition of an asset or management’s interest in selling the asset are generally viewed as triggering events to reassess cash flows.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at the lower of depreciated historical cost net of any disallowances or fair value, if impaired. The Duke Energy Registrants capitalize all construction-related direct labor and material costs, as well as indirect construction costs such as general engineering, taxes and financing costs. See “Allowance for Funds Used During Construction (AFUDC) and Interest Capitalized” for information on capitalized financing costs. Costs of renewals and betterments that extend the useful life of property, plant and equipment are also capitalized. The cost of repairs, replacements and major maintenance projects, which do not extend the useful life or increase the expected output of the asset, are expensed as incurred. Depreciation is generally computed over the estimated useful life of the asset using the composite straight-line method. Depreciation studies are conducted periodically to update composite rates and are approved by state utility commissions and/or the FERC when required. The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. In general, when the Duke Energy Registrants retire regulated property, plant and equipment, the original cost plus the cost of retirement, less salvage value, is charged to accumulated depreciation. However, when it becomes probable the asset will be retired substantially in advance of its original expected useful life or is abandoned, the cost of the asset and the corresponding accumulated depreciation is recognized as a separate asset. If the asset is still in operation, the net amount is classified as Generation facilities to be retired, net on the Consolidated Balance Sheets. If the asset is no longer operating, the net amount is classified in Regulatory Assets on the Consolidated Balance Sheets. When it becomes probable that meters or other regulated mass utility assets will be abandoned, the cost of the asset and accumulated depreciation is reclassified to regulatory assets for amounts recoverable in rates. The carrying value of the asset is based on historical cost if the Duke Energy Registrants are allowed to recover the remaining net book value and a return equal to at least the incremental borrowing rate. If not, an impairment is recognized to the extent the net book value of the asset exceeds the present value of future revenues discounted at the incremental borrowing rate. When the Duke Energy Registrants sell entire regulated operating units, or retire or sell nonregulated properties, the original cost and accumulated depreciation and amortization balances are removed from Property, Plant and Equipment on the Consolidated Balance Sheets. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body. See Note 10 for further information.
Nuclear Fuel	Nuclear Fuel Nuclear fuel is classified as Property, Plant and Equipment on the Consolidated Balance Sheets, except for Duke Energy Florida. Nuclear fuel amounts at Duke Energy Florida were reclassified to Regulatory assets pursuant to a settlement among Duke Energy Florida, the Florida Office of Public Counsel (Florida OPC) and other customer advocates (the 2013 Settlement). Portions of the nuclear fuel balances that were under contract for sale were subsequently moved to Other within Current Assets and Other within Investments and Other Assets on the Consolidated Balance Sheets. Nuclear fuel in the front-end fuel processing phase is considered work in progress and not amortized until placed in service. Amortization of nuclear fuel is included within Fuel used in electric generation and purchased power on the Consolidated Statements of Operations. Amortization is recorded using the units-of-production method.
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalized	Allowance for Funds Used During Construction and Interest Capitalized For regulated operations, the debt and equity costs of financing the construction of property, plant and equipment are reflected as AFUDC and capitalized as a component of the cost of property, plant and equipment. AFUDC equity is reported on the Consolidated Statements of Operations as non-cash income in Other income and expenses, net. AFUDC debt is reported as a non-cash offset to Interest Expense. After construction is completed, the Duke Energy Registrants are permitted to recover these costs through their inclusion in rate base and the corresponding subsequent depreciation or amortization of those regulated assets. AFUDC equity, a permanent difference for income taxes, reduces the effective tax rate (ETR) when capitalized and increases the ETR when depreciated or amortized. See Note 22 for additional information. For nonregulated operations, interest is capitalized during the construction phase with an offsetting non-cash credit to Interest Expense on the Consolidated Statements of Operations.
Asset Retirement Obligations	Asset Retirement Obligations Asset retirement obligations (AROs) are recognized for legal obligations associated with the retirement of property, plant and equipment. Substantially all AROs are related to regulated operations. When recording an ARO, the present value of the projected liability is recognized in the period in which it is incurred, if a reasonable estimate of fair value can be made. The liability is accreted over time. For operating plants, the present value of the liability is added to the cost of the associated asset and depreciated over the remaining life of the asset. For retired plants, the present value of the liability is recorded as a regulatory asset unless determined not to be recoverable. The present value of the initial obligation and subsequent updates are based on discounted cash flows, which include estimates regarding timing of future cash flows, selection of discount rates and cost escalation rates, among other factors. These estimates are subject to change. Depreciation expense is adjusted prospectively for any changes to the carrying amount of the associated asset. The Duke Energy Registrants receive amounts to fund the cost of the ARO for regulated operations through a combination of regulated revenues and earnings on the NDTF. As a result, amounts recovered in regulated revenues, earnings on the NDTF, accretion expense and depreciation of the associated asset are netted and deferred as a regulatory asset or liability. Obligations for nuclear decommissioning are based on site-specific cost studies. Duke Energy Carolinas and Duke Energy Progress assume prompt dismantlement of the nuclear facilities after operations are ceased. Duke Energy Florida assumes Crystal River Unit 3 Nuclear Plant (Crystal River Unit 3) will be placed into a safe storage configuration until eventual dismantlement is completed by 2074. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida also assume that spent fuel will be stored on-site until such time that it can be transferred to a yet to be built U.S. Department of Energy (DOE) facility. Obligations for closure of ash basins are based upon discounted cash flows of estimated costs for site-specific plans, if known, or probability weightings of the potential closure methods if the closure plans are under development and multiple closure options are being considered and evaluated on a site-by-site basis. See Note 9 for additional information
Revenue Recognition and Unbilled Revenue	Revenue Recognition and Unbilled Revenue Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy or natural gas delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills and meter reading schedules. Unbilled revenues are included within Receivables and Restricted receivables of VIEs on the Consolidated Balance Sheets as shown in the following table.
Derivatives and Hedging	Derivatives and Hedging Derivative and non-derivative instruments may be used in connection with commodity price and interest rate activities, including swaps, futures, forwards and options. All derivative instruments, except those that qualify for the normal purchase/normal sale (NPNS) exception, are recorded on the Consolidated Balance Sheets at fair value. Qualifying derivative instruments may be designated as either cash flow hedges or fair value hedges. Other derivative instruments (undesignated contracts) either have not been designated or do not qualify as hedges. The effective portion of the change in the fair value of cash flow hedges is recorded in AOCI. The effective portion of the change in the fair value of a fair value hedge is offset in net income by changes in the hedged item. For activity subject to regulatory accounting, gains and losses on derivative contracts are reflected as regulatory assets or liabilities and not as other comprehensive income or current period income. As a result, changes in fair value of these derivatives have no immediate earnings impact. Formal documentation, including transaction type and risk management strategy, is maintained for all contracts accounted for as a hedge. At inception and at least every three months thereafter, the hedge contract is assessed to see if it is highly effective in offsetting changes in cash flows or fair values of hedged items. See Note 14 for further information.
Captive Insurance Reserves	Captive Insurance Reserves Duke Energy has captive insurance subsidiaries that provide coverage, on an indemnity basis, to the Subsidiary Registrants as well as certain third parties, on a limited basis, for various business risks and losses, such as property, workers’ compensation and general liability. Liabilities include provisions for estimated losses incurred but not yet reported (IBNR), as well as estimated provisions for known claims. IBNR reserve estimates are primarily based upon historical loss experience, industry data and other actuarial assumptions. Reserve estimates are adjusted in future periods as actual losses differ from experience. Duke Energy, through its captive insurance entities, also has reinsurance coverage with third parties for certain losses above a per occurrence and/or aggregate retention. Receivables for reinsurance coverage are recognized when realization is deemed probable.
Unamortized Debt Premium, Discount and Expense	Unamortized Debt Premium, Discount and Expense Premiums, discounts and expenses incurred with the issuance of outstanding long-term debt are amortized over the term of the debt issue. The gain or loss on extinguishment associated with refinancing higher-cost debt obligations in the regulated operations is amortized. Amortization expense is recorded as Interest Expense in the Consolidated Statements of Operations and is reflected as Depreciation, amortization and accretion within Net cash provided by operating activities on the Consolidated Statements of Cash Flows. Premiums, discounts and expenses are presented as an adjustment to the carrying value of the debt amount and included in Long-Term Debt on the Consolidated Balance Sheets presented.
Loss Contingencies and Environmental Liabilities	Loss Contingencies and Environmental Liabilities Contingent losses are recorded when it is probable a loss has occurred and can be reasonably estimated. When a range of the probable loss exists and no amount within the range is a better estimate than any other amount, the minimum amount in the range is recorded. Unless otherwise required by GAAP, legal fees are expensed as incurred. Environmental liabilities are recorded on an undiscounted basis when environmental remediation or other liabilities become probable and can be reasonably estimated. Environmental expenditures related to past operations that do not generate current or future revenues are expensed. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Certain environmental expenditures receive regulatory accounting treatment and are recorded as regulatory assets. See Notes 4 and 5 for further information.
Pension and Other Post-Retirement Benefit Plans	Pension and Other Post-Retirement Benefit Plans Duke Energy maintains qualified, non-qualified and other post-retirement benefit plans. Eligible employees of the Subsidiary Registrants participate in the respective qualified, non-qualified and other post-retirement benefit plans and the Subsidiary Registrants are allocated their proportionate share of benefit costs. See Note 21 for further information, including significant accounting policies associated with these plans.
Severance and Special Termination Benefits	Severance and Special Termination Benefits Duke Energy has a severance plan under which, in general, the longer a terminated employee worked prior to termination the greater the amount of severance benefits. A liability for involuntary severance is recorded once an involuntary severance plan is committed to by management if involuntary severances are probable and can be reasonably estimated. For involuntary severance benefits incremental to its ongoing severance plan benefits, the fair value of the obligation is expensed at the communication date if there are no future service requirements or over the required future service period. From time to time, Duke Energy offers special termination benefits under voluntary severance programs. Special termination benefits are recorded immediately upon employee acceptance absent a significant retention period. Otherwise, the cost is recorded over the remaining service period. Employee acceptance of voluntary severance benefits is determined by management based on the facts and circumstances of the benefits being offered. See Note 19 for further information.
Guarantees	Guarantees Liabilities are recognized at the time of issuance or material modification of a guarantee for the estimated fair value of the obligation it assumes. Fair value is estimated using a probability-weighted approach. The obligation is reduced over the term of the guarantee or related contract in a systematic and rational method as risk is reduced. Any additional contingent loss for guarantee contracts subsequent to the initial recognition of a liability is accounted for and recognized at the time a loss is probable and can be reasonably estimated. See Note 7 for further information.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation represents costs related to stock-based awards granted to employees and Duke Energy Board of Directors (Board of Directors) members. Duke Energy recognizes stock-based compensation based upon the estimated fair value of awards, net of estimated forfeitures at the date of issuance. The recognition period for these costs begins at either the applicable service inception date or grant date and continues throughout the requisite service period. Compensation cost is recognized as expense or capitalized as a component of property, plant and equipment. See Note 20 for further information.
Income Taxes	Income Taxes Duke Energy and its subsidiaries file a consolidated federal income tax return and other state and foreign jurisdictional returns. The Subsidiary Registrants entered into a tax-sharing agreement with Duke Energy. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. Deferred income taxes have been provided for temporary differences between GAAP and tax bases of assets and liabilities because the differences create taxable or tax-deductible amounts for future periods. Investment tax credits (ITCs) associated with regulated operations are deferred and amortized as a reduction of income tax expense over the estimated useful lives of the related properties. Positions taken or expected to be taken on tax returns, including the decision to exclude certain income or transactions from a return, are recognized in the financial statements when it is more likely than not the tax position can be sustained based solely on the technical merits of the position. The largest amount of tax benefit that is greater than 50 percent likely of being effectively settled is recorded. Management considers a tax position effectively settled when: (i) the taxing authority has completed its examination procedures, including all appeals and administrative reviews; (ii) the Duke Energy Registrants do not intend to appeal or litigate the tax position included in the completed examination; and (iii) it is remote that the taxing authority would examine or re-examine the tax position. The amount of a tax return position that is not recognized in the financial statements is disclosed as an unrecognized tax benefit. If these unrecognized tax benefits are later recognized, then there will be a decrease in income tax expense or a reclassification between deferred and current taxes payable. If the portion of tax benefits that has been recognized changes and those tax benefits are subsequently unrecognized, then the previously recognized tax benefits may impact the financial statements through increasing income tax expense or a reclassification between deferred and current taxes payable. Changes in assumptions on tax benefits may also impact interest expense or interest income and may result in the recognition of tax penalties. Tax-related interest and penalties are recorded in Interest Expense and Other Income and Expenses, net in the Consolidated Statements of Operations. See Note 22 for further information.
Accounting for Renewable Energy Tax Credits and Cash Grants	Accounting for Renewable Energy Tax Credits and Cash Grants When Duke Energy receives ITCs or cash grants on wind or solar facilities, it reduces the basis of the property recorded on the Consolidated Balance Sheets by the amount of the ITC or cash grant and, therefore, the ITC or grant benefit is ultimately recognized in the statement of operations through reduced depreciation expense. Additionally, certain tax credits and government grants result in an initial tax depreciable base in excess of the book carrying value by an amount equal to one half of the ITC or government grant. Deferred tax benefits are recorded as a reduction to income tax expense in the period that the basis difference is created.
Excise Taxes	Excise Taxes Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Otherwise, the taxes are accounted for net. Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes in the Consolidated Statements of Operations were as follows.
Dividend Restrictions and Unappropriated Retained Earnings	Dividend Restrictions and Unappropriated Retained Earnings Duke Energy does not have any legal, regulatory or other restrictions on paying common stock dividends to shareholders. However, as further described in Note 4 , due to conditions established by regulators in conjunction with merger transaction approvals, Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio, Duke Energy Indiana and Piedmont have restrictions on paying dividends or otherwise advancing funds to Duke Energy. At December 31, 2016 and 2015 , an insignificant amount of Duke Energy’s consolidated Retained earnings balance represents undistributed earnings of equity method investments.
New Accounting Standards	New Accounting Standards The following new accounting standards have been issued, but have not yet been adopted by the Duke Energy Registrants, as of December 31, 2016 . Goodwill Impairment. In January 2017, the Financial Accounting Standards Board (FASB) issued revised guidance for subsequent measurement of goodwill. Under the updated guidance, a company will recognize an impairment to goodwill for the amount by which a reporting unit's carrying value exceeds the reporting unit's fair value, not to exceed the amount of goodwill allocated to that reporting unit. Duke Energy is unable to determine the future impact of adopting this guidance. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2020, but may be early adopted for interim or annual goodwill tests performed on testing dates after January 1, 2017. The guidance will be applied on a prospective basis. Revenue from Contracts with Customers . In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Most of Duke Energy’s revenue is expected to be in scope of the new guidance. The majority of our sales, including energy provided to residential customers, are from tariff offerings that provide natural gas or electricity without a defined contractual term (‘at-will’). For such arrangements, Duke Energy expects that the revenue from contracts with customers will be equivalent to the electricity or natural gas supplied and billed in that period (including estimated billings). As such, Duke Energy does not expect that there will be a significant shift in the timing or pattern of revenue recognition for such sales. The evaluation of other revenue streams is ongoing, including long-term contracts with industrial customers and long-term purchase power agreements (PPA). Duke Energy continues to evaluate what information would be most useful for users of the financial statements, including information already provided in disclosures outside of the financial statement footnotes. These additional disclosures could include the disaggregation of revenues by geographic location, type of service, customer class or by duration of contract (‘at-will’ versus contracted revenue). Revenues from contracts with customers, revenue recognized under regulated operations accounting and revenue from lease accounting will also be disclosed. Duke Energy intends to use the modified retrospective method of adoption effective January 1, 2018. This method results in a cumulative change effect that will be recorded as an adjustment to retained earnings as of January 1, 2018, as if the standard had always been in effect. Disclosures for 2018 will include a comparison to what would have been reported for 2018 under the current revenue recognition rules in order to assist financial statement users in understanding how revenue recognition has changed as a result of this standard and to facilitate comparability with prior year reported results, which are not restated under the modified retrospective approach. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2019, although it can be early adopted. The guidance is applied using a modified retrospective approach. Duke Energy is currently evaluating the financial statement impact of adopting this standard. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Significant system enhancements may be required to facilitate the identification, tracking and reporting of potential leases based upon requirements of the new lease standard. Stock-Based Compensation and Income Taxes. In March 2016, the FASB issued revised accounting guidance for stock-based compensation and the associated income taxes. This standard changes certain aspects of accounting for stock-based payment awards to employees including the accounting for income taxes, statutory tax withholding requirements, as well as classification on the Consolidated Statements of Cash Flows. The primary future impact to the Duke Energy Registrants is expected to be a small increase in the volatility of income tax expense. This guidance will be adopted prospectively, retrospectively, or using a modified retrospective approach depending on the item changed for the period beginning January 1, 2017. Statement of Cash Flows. In November 2016, the FASB issued revised accounting guidance to reduce diversity in practice for the presentation and classification of restricted cash on the statement of cash flows. Under the updated guidance, restricted cash and restricted cash equivalents will be included within beginning-of-period and end-of-period cash and cash equivalents on the statement of cash flows. For Duke Energy, this guidance is effective for the interim and annual periods beginning January 1, 2018, although it can be early adopted. The guidance will be applied using a retrospective transition method to each period presented. Upon adoption by Duke Energy, the revised guidance will result in a change in total cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents explained when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Prior to adoption, the Duke Energy Registrants reflect changes in restricted cash within Cash Flows from Investing Activities on the Consolidated Statement of Cash Flows. Financial Instruments Classification and Measurement. In January 2016, the FASB issued revised accounting guidance for the classification and measurement of financial instruments. Changes in the fair value of all equity securities will be required to be recorded in net income. Current GAAP allows some changes in fair value for available-for-sale equity securities to be recorded in AOCI. Additional disclosures will be required to present separately the financial assets and financial liabilities by measurement category and form of financial asset. An entity's equity investments that are accounted for under the equity method of accounting are not included within the scope of the new guidance. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, by recording a cumulative change effect that will be recorded as an adjustment to retained earnings as of January 1, 2018. This guidance is expected to have minimal impact on the Duke Energy Registrant's Consolidated Statements of Operations and Comprehensive Income as changes in the fair value of most of the Duke Energy Registrants' available-for-sale equity securities are deferred as regulatory assets or liabilities pursuant to accounting guidance for regulated operations.
Duke Energy Ohio [Member]
Policy Text Block [Line Items]
Revenue Recognition and Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company LLC (CRC) and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 17 for further information.
Duke Energy Indiana [Member]
Policy Text Block [Line Items]
Revenue Recognition and Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company LLC (CRC) and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 17 for further information.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Organization And Basis Of Presentation [Line Items]
Schedule of Current and Noncurrent Assets and Liabilities	The following table provides a description of amounts included in Other within Current Assets or Current Liabilities that exceed 5 percent of total Current Assets or Current Liabilities on the Duke Energy Registrants' Consolidated Balance Sheets at either December 31, 2016 or 2015 . December 31, (in millions) Location 2016 2015 Duke Energy Accrued compensation Current Liabilities $ 765 $ 619 Duke Energy Carolinas Accrued compensation Current Liabilities $ 248 $ 213 Collateral liabilities Current Liabilities 155 141 Progress Energy Income taxes receivable Current Assets $ 19 $ 129 Customer deposits Current Liabilities 363 373 Derivative liabilities Current Liabilities 1 201 Duke Energy Progress Income taxes receivable Current Assets $ 16 $ 111 Customer deposits Current Liabilities 141 141 Accrued compensation Current Liabilities 135 108 Derivative liabilities Current Liabilities — 76 Duke Energy Florida Customer deposits Current Liabilities $ 222 $ 232 Derivative liabilities Current Liabilities 1 125 Duke Energy Ohio Income taxes receivable Current Assets $ 16 $ 59 Other receivable Current Assets — 33 Accrued litigation reserve Current Liabilities 4 80 Collateral liabilities Current Liabilities 62 48 Duke Energy Indiana Collateral liabilities Current Liabilities $ 44 $ 44
Schedule of Net Income Amounts Attributable to Controlling Interests	The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations. Year ended December 31, (in millions) 2016 2015 2014 Income from Continuing Operations $ 2,578 $ 2,654 $ 2,538 Income from Continuing Operations Attributable to Noncontrolling Interests 7 9 5 Income from Continuing Operations Attributable to Duke Energy Corporation $ 2,571 $ 2,645 $ 2,533 (Loss) Income From Discontinued Operations, net of tax $ (408 ) $ 177 $ (649 ) Income from Discontinued Operations Attributable to Noncontrolling Interests, net of tax 11 6 1 (Loss) Income From Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ (419 ) $ 171 $ (650 ) Net Income $ 2,170 $ 2,831 $ 1,889 Net Income Attributable to Noncontrolling Interests 18 15 6 Net Income Attributable to Duke Energy Corporation $ 2,152 $ 2,816 $ 1,883
Components Of Inventory	The components of inventory are presented in the tables below. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,374 $ 767 $ 1,167 $ 813 $ 354 $ 84 $ 312 Coal 774 251 314 148 166 19 190 Natural gas, oil and other 374 37 236 115 121 34 2 Total inventory $ 3,522 $ 1,055 $ 1,717 $ 1,076 $ 641 $ 137 $ 504 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,343 $ 785 $ 1,133 $ 776 $ 357 $ 81 $ 301 Coal 1,105 451 370 192 178 16 267 Natural gas, oil and other 298 40 248 120 128 8 2 Total inventory $ 3,746 $ 1,276 $ 1,751 $ 1,088 $ 663 $ 105 $ 570
Schedule Of Property, Plant And Equipment	The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2016 2015 2014 Duke Energy 2.8 % 2.9 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.7 % Progress Energy 2.7 % 2.6 % 2.5 % Duke Energy Progress 2.6 % 2.6 % 2.5 % Duke Energy Florida 2.8 % 2.7 % 2.7 % Duke Energy Ohio 2.6 % 2.7 % 2.3 % Duke Energy Indiana 3.1 % 3.0 % 3.0 % The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2016 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,501 $ 432 $ 735 $ 393 $ 342 $ 150 $ 106 Plant – Regulated Electric generation, distribution and transmission 8 - 100 89,864 34,515 37,596 23,683 13,913 4,593 13,160 Natural gas transmission and distribution 12 - 67 7,738 — — — — 2,456 — Other buildings and improvements 15 - 100 1,692 502 634 293 341 211 197 Plant – Nonregulated Electric generation, distribution and transmission 5 - 30 4,298 — — — — — — Other buildings and improvements 25 - 35 421 — — — — — — Nuclear fuel 3,572 2,092 1,480 1,480 — — — Equipment 3 - 38 1,941 358 505 378 127 338 156 Construction in process 6,186 2,324 2,708 1,329 1,379 206 396 Other 5 - 40 4,184 904 1,206 863 332 172 226 Total property, plant and equipment (a)(d) 121,397 41,127 44,864 28,419 16,434 8,126 14,241 Total accumulated depreciation – regulated (b)(c)(d) (37,831 ) (14,365 ) (15,212 ) (10,561 ) (4,644 ) (2,579 ) (4,317 ) Total accumulated depreciation – nonregulated (c)(d) (1,575 ) — — — — — — Generation facilities to be retired, net 529 — 529 529 — — — Total net property, plant and equipment $ 82,520 $ 26,762 $ 30,181 $ 18,387 $ 11,790 $ 5,547 $ 9,924 (a) Includes capitalized leases of $1,355 million , $40 million , $288 million , $142 million , $146 million , $81 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $99 million , $9 million and $90 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,922 million , $1,192 million , $730 million and $730 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $50 million , $9 million , $19 million and $8 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,591 million and accumulated depreciation of consolidated VIEs of $411 million at Duke Energy. December 31, 2015 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,391 $ 407 $ 719 $ 392 $ 327 $ 118 $ 108 Plant – Regulated Electric generation, distribution and transmission 8 - 100 87,593 33,623 36,422 22,888 13,534 4,429 13,118 Natural gas transmission and distribution 12 - 67 2,322 — — — — 2,322 — Other buildings and improvements 15 - 100 1,480 477 621 294 322 204 179 Plant – Nonregulated Electric generation, distribution and transmission 1 - 30 3,348 — — — — — — Other buildings and improvements 25 - 35 410 — — — — — — Nuclear fuel 3,194 1,827 1,367 1,367 — — — Equipment 3 - 38 1,736 368 530 398 132 344 173 Construction in process 4,485 1,860 1,827 1,118 709 180 214 Other 5 - 60 4,008 836 1,180 856 319 153 215 Total property, plant and equipment (a)(d) 109,967 39,398 42,666 27,313 15,343 7,750 14,007 Total accumulated depreciation – regulated (b)(c)(d) (35,367 ) (13,521 ) (14,867 ) (10,141 ) (4,720 ) (2,507 ) (4,484 ) Total accumulated depreciation – nonregulated (c)(d) (1,369 ) — — — — — — Generation facilities to be retired, net 548 — 548 548 — — — Total net property, plant and equipment $ 73,779 $ 25,877 $ 28,347 $ 17,720 $ 10,623 $ 5,243 $ 9,523 (a) Includes capitalized leases of $1,465 million , $40 million , $302 million , $144 million , $158 million , $96 million and $39 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily in regulated plant. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $85 million , $7 million and $78 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,621 million , $976 million , $645 million and $645 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $57 million , $11 million , $27 million and $7 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,033 million and accumulated depreciation of consolidated VIEs of $327 million at Duke Energy.
Schedule of Allowance for Doubtful Accounts	Allowances for doubtful accounts are presented in the following table. December 31, (in millions) 2016 2015 2014 Allowance for Doubtful Accounts Duke Energy $ 14 $ 12 $ 14 Duke Energy Carolinas 2 3 3 Progress Energy 6 6 8 Duke Energy Progress 4 4 7 Duke Energy Florida 2 2 2 Duke Energy Ohio 2 2 2 Duke Energy Indiana 1 1 1 Allowance for Doubtful Accounts – VIEs Duke Energy $ 54 $ 53 $ 51 Duke Energy Carolinas 7 7 6 Progress Energy 7 8 8 Duke Energy Progress 5 5 5 Duke Energy Florida 2 3 3
Schedule of Excise Taxes	Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes in the Consolidated Statements of Operations were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 362 $ 396 $ 498 Duke Energy Carolinas 31 31 94 Progress Energy 213 229 263 Duke Energy Progress 18 16 56 Duke Energy Florida 195 213 207 Duke Energy Ohio 100 102 103 Duke Energy Indiana 17 34 38
Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues Within Receivables and Restricted Receivables	Unbilled revenues are included within Receivables and Restricted receivables of VIEs on the Consolidated Balance Sheets as shown in the following table. December 31, (in millions) 2016 2015 Duke Energy $ 831 $ 677 Duke Energy Carolinas 313 283 Progress Energy 161 172 Duke Energy Progress 102 102 Duke Energy Florida 59 70 Duke Energy Ohio 2 3 Duke Energy Indiana 32 31 Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company LLC (CRC) and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 17 for further information. These receivables for unbilled revenues are shown in the table below. December 31, (in millions) 2016 2015 Duke Energy Ohio $ 97 $ 71 Duke Energy Indiana 123 97

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired	The preliminary purchase price allocation of the Piedmont acquisition is estimated as follows: (in millions) Current assets $ 497 Property, plant and equipment, net 4,714 Goodwill 3,353 Other long-term assets 804 Total assets 9,368 Current liabilities, including current maturities of long-term debt 576 Long-term liabilities 1,790 Long-term debt 2,002 Total liabilities 4,368 Total purchase price $ 5,000 The assets acquired are presented in the following table. (in millions) Inventory $ 56 Net property, plant and equipment 845 Total assets 901 Acquisition adjustment, recorded within property, plant and equipment 350 Total purchase price $ 1,251
Business Acquisition, Pro Forma Information	This information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Duke Energy. Years Ended December 31, (in millions) 2016 2015 Operating Revenues $ 23,504 $ 23,570 Net Income Attributable to Duke Energy Corporation 2,442 2,877
Disposal Groups, Including Discontinued Operations	The following table presents the results of the International Disposal Group which are included in (Loss) Income from Discontinued Operations, net of tax in Duke Energy's Consolidated Statements of Operations. Years Ended December 31, (in millions) 2016 2015 2014 Operating Revenues $ 988 $ 1,088 $ 1,417 Fuel used in electric generation and purchased power 227 306 486 Cost of natural gas 43 53 63 Operation, maintenance and other 341 334 352 Depreciation and amortization (a) 62 92 97 Property and other taxes 15 7 9 Impairment charges (b) 194 13 — (Loss) Gains on Sales of Other Assets and Other, net (3 ) 6 6 Other Income and Expenses, net 58 23 47 Interest Expense 82 85 93 Pretax loss on disposal (c) (514 ) — — (Loss) Income before income taxes (d) (435 ) 227 370 Income tax expense (e)(f) 99 70 443 (Loss) Income from discontinued operations of the International Disposal Group $ (534 ) $ 157 $ (73 ) (a) Upon meeting the criteria for assets held for sale, beginning in the fourth quarter of 2016 depreciation expense was ceased. (b) In conjunction with the advancements of marketing efforts during 2016, Duke Energy performed recoverability tests of the long-lived asset groups of International Energy. As a result, Duke Energy determined the carrying value of certain assets in Central America was not fully recoverable and recorded a pretax impairment charge of $194 million . The charge represents the excess of carrying value over the estimated fair value of the assets, which was based on a Level 3 Fair Value measurement that was primarily determined from the income approach using discounted cash flows but also considered market information obtained in 2016. (c) The pretax loss on disposal includes the recognition of cumulative foreign currency translation losses of $620 million as of the disposal date. See the Consolidated Statements of Changes in Equity for additional information. (d) Pretax (Loss) Income attributable to Duke Energy Corporation was $(445) million , $221 million and $360 million for the years ended December 31, 2016, 2015 and 2014, respectively. (e) 2016 amount includes $126 million of income tax expense on the disposal, which primarily reflects in-country taxes incurred as a result of the sale. The after-tax loss on disposal was $640 million . (f) 2016 amount includes an income tax benefit of $95 million and 2014 amount includes an income tax charge of $373 million related to historical undistributed foreign earnings. See Note 22, "Income Taxes," for additional information. The following table summarizes the (Loss) Income from Discontinued Operations, net of tax recorded on Duke Energy's Consolidated Statements of Operations: Years Ended December 31, (in millions) 2016 2015 2014 International Energy Disposal Group $ (534 ) $ 157 $ (73 ) Midwest Generation Disposal Group 36 33 (524 ) Other (a) 90 (13 ) (52 ) (Loss) Income from Discontinued Operations, net of tax $ (408 ) $ 177 $ (649 ) (a) Relates to previously sold businesses not related to the Disposal Groups. The amount for 2016 represents an income tax benefit resulting from immaterial out of period deferred tax liability adjustments. The amounts for 2015 and 2014 include indemnifications provided for certain legal, tax and environmental matters and foreign currency translation adjustments. The following table summarizes the Midwest Generation Disposal Group activity recorded within discontinued operations. Duke Energy Duke Energy Ohio Years Ended December 31, Years Ended December 31, (in millions) 2016 2015 2014 2016 2015 2014 Operating Revenues $ — $ 543 $ 1,748 $ — $ 412 $ 1,299 Pretax Loss on disposal (a) — (45 ) (929 ) — (52 ) (959 ) Income (loss) before income taxes (b) $ — $ 59 $ (818 ) $ — $ 44 $ (863 ) Income tax (benefit) expense (c) (36 ) 26 (294 ) (36 ) 21 (300 ) Income (loss) from discontinued operations $ 36 $ 33 $ (524 ) $ 36 $ 23 $ (563 ) (a) The Loss on disposal includes impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) 2015 amounts include the impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information about the lawsuit. (c) 2016 amounts result from immaterial out of period deferred tax liability adjustments.
Disclosure of Long Lived Assets Held-for-sale	The following table presents the carrying values of the major classes of Assets held for sale and Liabilities associated with assets held for sale included in the Consolidated Balance Sheets. As a result of Duke Energy closing both transactions in December 2016, there are no Assets held for sale or Liabilities associated with assets held for sale as of December 31, 2016. (in millions) December 31, 2015 Current assets held for sale Cash and cash equivalents $ 474 Receivables, net 188 Inventory 65 Other 19 Total current assets held for sale 746 Noncurrent assets held for sale Property, Plant and Equipment Cost 2,859 Accumulated depreciation and amortization (930 ) Net property, plant and equipment 1,929 Goodwill 271 Other 213 Total noncurrent assets held for sale 2,413 Total assets held for sale $ 3,159 Current liabilities associated with assets held for sale Accounts payable $ 51 Taxes accrued 60 Current maturities of long-term debt 48 Other 120 Total current liabilities associated with assets held for sale 279 Noncurrent liabilities associated with assets held for sale Long-Term Debt 653 Deferred income taxes 157 Other 90 Total noncurrent liabilities associated with assets held for sale 900 Total liabilities associated with assets held for sale $ 1,179 The value of goodwill increased by $7 million from December 31, 2015 through the date of sale as a result of changes in foreign currency exchanges rates. At the time of the disposition, the International Disposal Group included goodwill of $278 million .
Schedule of Cash Flow, Supplemental Disclosures	The following table summarizes Duke Energy's cash flows from discontinued operations related to the International Disposal Group. Years Ended December 31, (in millions) 2016 2015 2014 Cash flows provided by (used in): Operating activities $ 204 $ 248 $ 339 Investing activities (434 ) 177 111

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting Information [Line Items]
Business Segment Data	The following table summarizes the net loss for Other for each of these entities. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas $ (104 ) $ (95 ) $ (79 ) Progress Energy (200 ) (159 ) (190 ) Duke Energy Progress (56 ) (32 ) (31 ) Duke Energy Florida (23 ) (16 ) (19 ) Duke Energy Indiana (13 ) (10 ) (11 ) Year Ended December 31, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,336 $ 875 $ 484 $ 22,695 $ 48 $ — $ 22,743 Intersegment Revenues 30 26 — 56 69 (125 ) — Total Revenues $ 21,366 $ 901 $ 484 $ 22,751 $ 117 $ (125 ) $ 22,743 Interest Expense $ 1,136 $ 46 $ 53 $ 1,235 $ 693 $ (12 ) $ 1,916 Depreciation and amortization 2,897 115 130 3,142 152 — 3,294 Equity in earnings (losses) of unconsolidated affiliates (a) 5 19 (82 ) (58 ) 43 — (15 ) Income tax expense (benefit) 1,672 90 (160 ) 1,602 (446 ) — 1,156 Segment income (loss) (b)(c) 3,040 152 23 3,215 (645 ) 1 2,571 Add back noncontrolling interest component 7 Loss from discontinued operations, net of tax (d) (408 ) Net income $ 2,170 Capital investments expenditures and acquisitions (e) $ 6,649 $ 5,519 $ 857 $ 13,025 $ 190 $ — $ 13,215 Segment assets 114,993 10,760 4,377 130,130 2,443 188 132,761 (a) Commercial Renewables includes a pretax impairment charge of $71 million . See Note 12 for additional information. (b) Other includes $329 million of after-tax costs to achieve mergers. Refer to Note 2 for additional information on costs related to the Piedmont merger. (c) Other includes after-tax charges of $57 million related to cost savings initiatives. Refer to Note 19 for further information. (d) Includes a loss on sale of the International Disposal Group. Refer to Note 2 for further information. (e) Other includes $26 million of capital investments expenditures related to the International Disposal Group. Gas Utilities and Infrastructure includes the Piedmont acquisition of $5 billion . Refer to Note 2 for more information on the Piedmont acquisition. Year Ended December 31, 2015 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,489 $ 536 $ 286 $ 22,311 $ 60 $ — $ 22,371 Intersegment Revenues 32 5 — 37 75 (112 ) — Total Revenues $ 21,521 $ 541 $ 286 $ 22,348 $ 135 $ (112 ) $ 22,371 Interest Expense $ 1,074 $ 25 $ 44 $ 1,143 $ 393 $ (9 ) $ 1,527 Depreciation and amortization 2,735 79 104 2,918 135 — 3,053 Equity in earnings (losses) of unconsolidated affiliates (2 ) 1 (6 ) (7 ) 76 — 69 Income tax expense (benefit) 1,602 44 (128 ) 1,518 (262 ) — 1,256 Segment income (loss) (a)(b)(c) 2,819 73 52 2,944 (299 ) — 2,645 Add back noncontrolling interest component 9 Income from discontinued operations, net of tax (d) 177 Net income $ 2,831 Capital investments expenditures and acquisitions (e) $ 6,852 $ 234 $ 1,019 $ 8,105 $ 258 $ — $ 8,363 Segment assets (f) 109,097 2,637 3,861 115,595 5,373 188 121,156 (a) Electric Utilities and Infrastructure includes an after-tax charge of $58 million related to the Edwardsport settlement. Refer to Note 4 for further information. (b) Other includes $60 million of after-tax costs to achieve mergers. (c) Other includes after-tax charges of $77 million related to cost savings initiatives. Refer to Note 19 for further information. (d) Includes the impact of a settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information related to the lawsuit and Note 2 for further information on discontinued operations. (e) Other includes capital investment expenditures of $45 million related to the International Disposal Group. (f) Other includes Assets Held for Sale balances related to the International Disposal Group. Refer to Note 2 for further information. Year Ended December 31, 2014 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Total Unaffiliated Revenues $ 21,655 $ 573 $ 235 $ 22,463 $ 46 $ — $ 22,509 Intersegment Revenues 36 5 1 42 70 (112 ) — Total Revenues $ 21,691 $ 578 $ 236 $ 22,505 $ 116 $ (112 ) $ 22,509 Interest Expense $ 1,057 $ 37 $ 50 $ 1,144 $ 409 $ (24 ) $ 1,529 Depreciation and amortization 2,686 73 90 2,849 120 — 2,969 Equity in earnings (losses) of unconsolidated affiliates (1 ) — 8 7 123 — 130 Income tax expense (benefit) 1,582 45 (88 ) 1,539 (314 ) — 1,225 Segment income (loss) (a)(b) 2,714 80 53 2,847 (332 ) 18 2,533 Add back noncontrolling interest component 5 Loss from discontinued operations, net of tax (c) (649 ) Net income $ 1,889 Capital investments expenditures and acquisitions (d) $ 4,642 $ 121 $ 514 $ 5,277 $ 251 $ — $ 5,528 Segment assets (e) 104,119 2,512 2,981 109,612 10,755 190 120,557 (a) Other includes a $94 million pretax impairment charge related to Ohio Valley Electric Corporation (OVEC) and costs to achieve mergers. (b) Electric Utilities and Infrastructure includes pretax charges of $102 million related to the criminal investigation of the Dan River coal ash spill. See Note 5 for additional information. (c) Includes an impairment of the Midwest Generation Disposal Group. Refer to Note 2 for further information. (d) Other includes $67 million of capital investments expenditures and acquisitions of the International Disposal Group. (e) Other includes Assets Held for Sale balances related to the International Disposal Group and Midwest Generation Disposal Group. Refer to Note 2 for further information.
Schedule of Revenue, By Products and Services	Products and Services The following table summarizes revenues of the reportable segments by type. Retail Wholesale Retail Total (in millions) Electric Electric Natural Gas Other Revenues 2016 Electric Utilities and Infrastructure $ 18,338 $ 2,095 $ — $ 933 $ 21,366 Gas Utilities and Infrastructure — — 871 30 901 Commercial Renewables — 303 — 181 484 Total Reportable Segments $ 18,338 $ 2,398 $ 871 $ 1,144 $ 22,751 2015 Electric Utilities and Infrastructure $ 18,695 $ 2,014 $ — $ 812 $ 21,521 Gas Utilities and Infrastructure — — 546 (5 ) 541 Commercial Renewables — 245 — 41 286 Total Reportable Segments $ 18,695 $ 2,259 $ 546 $ 848 $ 22,348 2014 Electric Utilities and Infrastructure $ 19,007 $ 1,879 $ — $ 805 $ 21,691 Gas Utilities and Infrastructure — — 571 7 578 Commercial Renewables — 236 — — 236 Total Reportable Segments $ 19,007 $ 2,115 $ 571 $ 812 $ 22,505
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	Year Ended December 31, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,410 $ 503 $ 1,913 $ 31 $ — $ 1,944 Interest expense $ 58 $ 27 $ 85 $ 1 $ — $ 86 Depreciation and amortization 151 80 231 2 — 233 Income tax expense (benefit) 55 44 99 (21 ) — 78 Segment income (loss) 154 77 231 (39 ) — 192 Income from discontinued operations, net of tax 36 Net income $ 228 Capital expenditures $ 322 $ 154 $ 476 $ — $ — $ 476 Segment assets 4,782 2,696 7,478 62 (12 ) 7,528 Year Ended December 31, 2015 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,331 $ 541 $ 1,872 $ 33 $ — $ 1,905 Interest expense $ 53 $ 25 $ 78 $ 1 $ — $ 79 Depreciation and amortization 147 79 226 1 — 227 Income tax expense (benefit) 59 45 104 (23 ) — 81 Segment income (loss) 118 73 191 (41 ) (1 ) 149 Income from discontinued operations, net of tax 23 Net income $ 172 Capital expenditures $ 264 $ 135 $ 399 $ — $ — $ 399 Segment assets 4,534 2,516 7,050 56 (9 ) 7,097 Year Ended December 31, 2014 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Eliminations Total Total revenues $ 1,317 $ 578 $ 1,895 $ 19 $ (1 ) $ 1,913 Interest expense $ 43 $ 37 $ 80 $ 5 $ 1 $ 86 Depreciation and amortization 138 73 211 3 — 214 Income tax expense (benefit) 71 45 116 (73 ) — 43 Segment income (loss) (a) 122 80 202 (133 ) (1 ) 68 Loss from discontinued operations, net of tax (b) (563 ) Net loss $ (495 ) Capital expenditures $ 193 $ 107 $ 300 $ 22 $ — $ 322 Segment assets (c) 4,428 2,487 6,915 3,321 (243 ) 9,993 (a) Other includes a $94 million pretax impairment charge related to OVEC. (b) Includes an impairment of the Midwest Generation Disposal Group. Refer to Note 2 for further information. (c) Other includes Assets Held for Sale balances related to the Midwest Generation Disposal Group. Refer to Note 2 for further information.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Assets AROs – coal ash $ 2,555 $ 1,120 $ 1,394 $ 1,386 $ 8 $ 4 $ 37 AROs – nuclear and other 838 104 487 195 292 — — Accrued pension and OPEB 2,151 479 807 366 441 139 220 Retired generation facilities 509 49 409 179 230 — 51 Debt fair value adjustment 1,191 — — — — — — Net regulatory asset related to income taxes 1,075 564 318 106 212 55 120 Nuclear asset securitizable balance, net 1,237 — 1,237 — 1,237 — — Hedge costs and other deferrals 571 127 410 171 239 7 27 DSM/EE 340 80 250 237 13 10 — Grid Modernization 68 — — — — 68 — Vacation accrual 192 79 38 38 — 5 10 Deferred fuel and purchased power 151 21 129 93 36 1 — Nuclear deferral 245 107 138 62 76 — — Post-in-service carrying costs and deferred operating expenses 383 97 38 38 — 21 227 Gasification services agreement buyout 32 — — — — — 32 Transmission expansion obligation 72 — — — — 72 — MGP 104 — — — — 104 — NCEMPA deferrals 21 — 21 21 — — — East Bend deferrals 16 — — — — 16 — Other 499 244 121 82 39 31 94 Total regulatory assets 12,250 3,071 5,797 2,974 2,823 533 818 Less: current portion 877 305 362 264 98 36 102 Total noncurrent regulatory assets $ 11,373 $ 2,766 $ 5,435 $ 2,710 $ 2,725 $ 497 $ 716 The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Assets AROs – coal ash $ 3,761 $ 1,536 $ 1,830 $ 1,822 $ 8 $ 12 $ 276 AROs – nuclear and other 684 9 569 275 294 — — Accrued pension and OPEB 2,387 481 882 423 458 135 222 Retired generation facilities 534 39 422 165 257 — 73 Debt fair value adjustment 1,313 — — — — — — Net regulatory asset related to income taxes 894 484 231 7 224 63 119 Storm cost deferrals 153 — 148 148 — 5 — Nuclear asset securitized balance, net 1,193 — 1,193 — 1,193 — — Hedge costs and other deferrals 217 93 91 66 25 7 26 Derivatives – gas supply contracts 187 — — — — — — Demand side management (DSM)/Energy efficiency (EE) 407 122 278 263 15 6 — Grid Modernization 65 — — — — 65 — Vacation accrual 196 76 38 38 — 4 10 Deferred fuel and purchased power 156 — 111 24 87 5 40 Nuclear deferral 226 92 134 38 96 — — Post-in-service carrying costs and deferred operating expenses 413 70 42 42 — 20 281 Gasification services agreement buyout 8 — — — — — 8 Transmission expansion obligation 71 — — — — 71 — Manufactured gas plant (MGP) 99 — — — — 99 — Advanced metering infrastructure 218 172 — — — — 46 NCEMPA deferrals 51 — 51 51 — — — East Bend deferrals 32 — — — — 32 — Other 636 223 103 69 36 33 121 Total regulatory assets 13,901 3,397 6,123 3,431 2,693 557 1,222 Less: current portion 1,023 238 401 188 213 37 149 Total noncurrent regulatory assets $ 12,878 $ 3,159 $ 5,722 $ 3,243 $ 2,480 $ 520 $ 1,073
Schedule Of Regulatory Liabilities	December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Liabilities Costs of removal $ 6,074 $ 2,476 $ 2,198 $ 1,840 $ 358 $ 212 $ 660 Amounts to be refunded to customers 45 — — — — — 45 Storm reserve 83 22 60 — 60 1 — Accrued pension and OPEB 174 46 — — — 19 72 Deferred fuel and purchased power 192 105 81 64 17 6 — Other 722 352 245 200 44 19 11 Total regulatory liabilities 7,290 3,001 2,584 2,104 479 257 788 Less: current portion 409 161 189 158 31 21 40 Total noncurrent regulatory liabilities $ 6,881 $ 2,840 $ 2,395 $ 1,946 $ 448 $ 236 $ 748 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory Liabilities Costs of removal $ 5,329 $ 2,413 $ 2,078 $ 1,725 $ 353 $ 222 $ 616 Amounts to be refunded to customers 71 — — — — — 71 Storm reserve 150 24 125 — 125 1 — Accrued pension and OPEB 288 68 51 25 26 21 83 Deferred fuel and purchased power 311 55 255 58 197 1 — Other 506 281 164 155 8 12 46 Total regulatory liabilities 6,655 2,841 2,673 1,963 709 257 816 Less: current portion 400 39 286 85 200 12 62 Total noncurrent regulatory liabilities $ 6,255 $ 2,802 $ 2,387 $ 1,878 $ 509 $ 245 $ 754
Schedule of Potential Plant Retirements	The table below contains the net carrying value of generating facilities planned for retirement or included in recent IRPs as evaluated for potential retirement due to a lack of requisite environmental control equipment. Dollar amounts in the table below are included in Net property, plant and equipment on the Consolidated Balance Sheets as of December 31, 2016 and exclude capitalized asset retirement costs. Remaining Net Capacity Book Value (in MW) (in millions) Duke Energy Carolinas Allen Steam Station Units 1-3 (a) 585 $ 168 Progress Energy and Duke Energy Florida Crystal River Units 1 and 2 873 120 Duke Energy Indiana (b) Gallagher Units 2 and 4 (c) 280 136 Total Duke Energy 1,738 $ 424 (a) Duke Energy Carolinas will retire Allen Steam Station Units 1 through 3 by December 31, 2024, as part of the resolution of a lawsuit involving alleged New Source Review violations. (b) Duke Energy Indiana retired Wabash River Units 2 through 6 in 2016. (c) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the settlement of Edwardsport IGCC matters.
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Schedule of MISO Exit Fee Obligations	The following table provides a reconciliation of the beginning and ending balance of Duke Energy Ohio’s recorded liability for its exit obligation and share of MTEP costs, excluding MVP, recorded within Other in Current liabilities and Other in Deferred credits and other liabilities on the Consolidated Balance Sheets. The retail portions of MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. As of December 31, 2016 and 2015, $71 million and $72 million are recorded in Regulatory assets on Duke Energy Ohio's Consolidated Balance Sheets, respectively. Provisions/ Cash (in millions) December 31, 2015 Adjustments Reductions December 31, 2016 Duke Energy Ohio $ 92 $ 3 $ (5 ) $ 90

Commitments and Contingencies (

Commitments and Contingencies (Table)	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Additional Possible Losses in Excess of Recorded Environmental Reserves	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 69 Duke Energy Carolinas 22 Duke Energy Ohio 36 Duke Energy Indiana 7
Schedule of Legal Reserves	The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves and the exit obligation discussed above related to the termination of an EPC contract. Reserves are classified on the Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. December 31, (in millions) 2016 2015 Reserves for Legal Matters Duke Energy $ 98 $ 156 Duke Energy Carolinas 23 11 Progress Energy 59 54 Duke Energy Progress 14 6 Duke Energy Florida 28 31 Duke Energy Ohio 4 80
Schedule of Purchase Power Obligations	The following table presents executory purchased power contracts with terms exceeding one year, excluding contracts classified as leases. Minimum Purchase Amount at December 31, 2016 Contract (in millions) Expiration 2017 2018 2019 2020 2021 Thereafter Total Duke Energy Progress (a) 2019-2031 $ 66 $ 67 $ 67 $ 50 $ 51 $ 267 $ 568 Duke Energy Florida (b) 2021-2043 341 357 377 394 376 1,211 3,056 Duke Energy Ohio (c)(d) 2018 203 89 — — — — 292 (a) Contracts represent between 15 percent and 100 percent of net plant output. (b) Contracts represent between 81 percent and 100 percent of net plant output. (c) Contracts represent between 1 percent and 11 percent of net plant output. (d) Excludes PPA with OVEC. See Note 17 for additional information.
Schedule of Natural Gas Supply Contract Commitments [Table Text Block]	The following table presents future unconditional purchase obligations under natural gas supply and capacity contracts as of December 31, 2016. (in millions) Duke Energy Duke Energy Ohio 2017 $ 371 $ 52 2018 308 35 2019 286 26 2020 269 22 2021 267 22 Thereafter 1,595 7 Total $ 3,096 $ 164
Schedule of Operating Lease Rent Expense	The following table presents rental expense for operating leases. These amounts are included in Operation, maintenance and other on the Consolidated Statements of Operations. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 242 $ 313 $ 350 Duke Energy Carolinas 45 41 41 Progress Energy 140 230 257 Duke Energy Progress 68 149 161 Duke Energy Florida 72 81 96 Duke Energy Ohio 16 13 17 Duke Energy Indiana 23 20 21
Schedule of Future Minimum Rental Payments for Operating Leases	The following table presents future minimum lease payments under operating leases, which at inception had a non-cancelable term of more than one year. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2017 $ 218 $ 41 $ 129 $ 75 $ 54 $ 12 $ 20 2018 205 35 126 73 53 11 17 2019 181 27 120 68 52 7 11 2020 164 23 109 58 51 6 10 2021 134 17 91 43 48 4 6 Thereafter 948 52 602 379 223 7 9 Total $ 1,850 $ 195 $ 1,177 $ 696 $ 481 $ 47 $ 73
Schedule of Future Minimum Lease Payments for Capital Leases	The following table presents future minimum lease payments under capital leases. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 2017 $ 148 $ 6 $ 46 $ 21 $ 25 $ 4 $ 1 2018 154 6 46 21 25 3 2 2019 154 6 45 20 25 1 1 2020 159 5 46 22 25 — 1 2021 163 1 45 20 25 — 1 Thereafter 784 30 322 250 71 — 41 Minimum annual payments 1,562 54 550 354 196 8 47 Less: amount representing interest (462 ) (32 ) (265 ) (212 ) (53 ) (1 ) (36 ) Total $ 1,100 $ 22 $ 285 $ 142 $ 143 $ 7 $ 11
Reserve for Environmental Costs [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Legal Reserves	The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Other within Deferred Credits and Other Liabilities on the Consolidated Balance Sheets. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2013 $ 74 $ 11 $ 27 $ 8 $ 19 $ 27 $ 7 Provisions/adjustments 32 (1 ) 1 4 (3 ) 28 4 Cash reductions (14 ) — (11 ) (7 ) (4 ) (1 ) (1 ) Balance at December 31, 2014 92 10 17 5 12 54 10 Provisions/adjustments 11 1 4 — 4 1 5 Cash reductions (9 ) (1 ) (4 ) (2 ) (2 ) (1 ) (3 ) Balance at December 31, 2015 94 10 17 3 14 54 12 Provisions/adjustments 19 4 7 2 4 7 1 Cash reductions (15 ) (4 ) (6 ) (2 ) (4 ) (2 ) (3 ) Balance at December 31, 2016 $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Debt	The following table shows the significant components of Current maturities of Long-Term Debt on the Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate December 31, 2016 Unsecured Debt Duke Energy (Parent) April 2017 1.226 % $ 400 Duke Energy (Parent) August 2017 1.625 % 700 Piedmont Natural Gas September 2017 8.510 % 35 First Mortgage Bonds Duke Energy Progress March 2017 1.146 % 250 Duke Energy Florida September 2017 5.800 % 250 Duke Energy Progress November 2017 1.111 % 200 Secured Duke Energy June 2017 2.365 % 45 Duke Energy June 2017 2.260 % 34 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Duke Energy Carolinas February 2017 0.810 % 10 Duke Energy Carolinas February 2017 0.790 % 25 Other (a) 293 Current maturities of long-term debt $ 2,319 (a) Includes capital lease obligations, amortizing debt and small bullet maturities. The following tables show short-term obligations classified as long-term debt. December 31, 2016 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 347 $ 35 $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 972 $ 335 $ 150 $ 52 $ 435 December 31, 2015 Duke Duke Duke Duke Duke Energy Energy Energy Energy (in millions) Energy Carolinas Progress Ohio Indiana Tax-exempt bonds $ 347 $ 35 $ — $ 27 $ 285 Commercial paper (a) 625 300 150 25 150 Total $ 972 $ 335 $ 150 $ 52 $ 435 (a) Progress Energy amounts are equal to Duke Energy Progress amounts. The following tables summarize outstanding debt. December 31, 2016 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Unsecured debt, maturing 2017 - 2073 4.30 % $ 17,812 $ 1,150 $ 3,551 $ — $ 150 $ 810 $ 415 Secured debt, maturing 2017 - 2037 2.60 % 3,909 425 1,819 300 1,519 — — First mortgage bonds, maturing 2017 - 2046 (a) 4.61 % 21,879 7,410 10,800 6,425 4,375 1,000 2,669 Capital leases, maturing 2018 - 2051 (b) 4.48 % 1,100 22 285 142 143 7 11 Tax-exempt bonds, maturing 2017 - 2041 (c) 2.84 % 1,053 355 48 48 — 77 572 Notes payable and commercial paper (d) 1.01 % 3,112 — — — — — — Money pool/intercompany borrowings (e) — 300 1,902 150 297 41 150 Fair value hedge carrying value adjustment 6 6 — — — — — Unamortized debt discount and premium, net (f) 1,753 (20 ) (31 ) (16 ) (10 ) (28 ) (9 ) Unamortized debt issuance costs (g) (242 ) (45 ) (104 ) (38 ) (52 ) (7 ) (22 ) Total debt 4.07 % $ 50,382 $ 9,603 $ 18,270 $ 7,011 $ 6,422 $ 1,900 $ 3,786 Short-term notes payable and commercial paper (2,487 ) — — — — — — Short-term money pool/intercompany borrowings — — (729 ) — (297 ) (16 ) — Current maturities of long-term debt (h) (2,319 ) (116 ) (778 ) (452 ) (326 ) (1 ) (3 ) Total long-term debt (h) $ 45,576 $ 9,487 $ 16,763 $ 6,559 $ 5,799 $ 1,883 $ 3,783 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $98 million and $670 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for Duke Energy and Piedmont's commercial paper programs were 14 days and eight days, respectively. (e) Progress Energy amount includes a $1 billion intercompany loan related to the sale of the International Disposal Group. See Note 2 for further discussion of the sale. (f) Duke Energy includes $1,653 million and $197 million in purchase accounting adjustments related to Progress Energy and Piedmont, respectively. (g) Duke Energy includes $53 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (h) Refer to Note 17 for additional information on amounts from consolidated VIEs. December 31, 2015 Weighted Average Duke Duke Duke Duke Duke Interest Duke Energy Progress Energy Energy Energy Energy (in millions) Rate Energy Carolinas Energy Progress Florida Ohio Indiana Unsecured debt, maturing 2016 - 2073 4.68 % $ 12,960 $ 1,152 $ 3,850 $ — $ 150 $ 765 $ 740 Secured debt, maturing 2016 - 2037 2.37 % 2,361 425 479 254 225 — — First mortgage bonds, maturing 2016 - 2045 (a) 4.74 % 18,980 6,161 9,750 5,975 3,775 750 2,319 Capital leases, maturing 2016 - 2051 (b) 5.39 % 1,335 24 300 144 156 13 14 Tax-exempt bonds, maturing 2017 - 2041 (c) 2.59 % 1,053 355 48 48 — 77 572 Notes payable and commercial paper (d) 0.88 % 4,258 — — — — — — Money pool/intercompany borrowings — 300 1,458 359 813 128 150 Fair value hedge carrying value adjustment 6 6 — — — — — Unamortized debt discount and premium, net (e) 1,712 (17 ) (28 ) (16 ) (8 ) (28 ) (8 ) Unamortized debt issuance costs (f) (164 ) (39 ) (85 ) (37 ) (32 ) (4 ) (19 ) Total debt 4.15 % $ 42,501 $ 8,367 $ 15,772 $ 6,727 $ 5,079 $ 1,701 $ 3,768 Short-term notes payable and commercial paper (3,633 ) — — — — — — Short-term money pool/intercompany borrowings — — (1,308 ) (209 ) (813 ) (103 ) — Current maturities of long-term debt (g) (2,026 ) (356 ) (315 ) (2 ) (13 ) (106 ) (547 ) Total long-term debt (g) $ 36,842 $ 8,011 $ 14,149 $ 6,516 $ 4,253 $ 1,492 $ 3,221 (a) Substantially all electric utility property is mortgaged under mortgage bond indentures. (b) Duke Energy includes $114 million and $731 million of capital lease purchase accounting adjustments related to Duke Energy Progress and Duke Energy Florida, respectively, related to power purchase agreements that are not accounted for as capital leases in their respective financial statements because of grandfathering provisions in GAAP. (c) Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit. (d) Includes $625 million that was classified as Long-Term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that backstop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted average days to maturity for commercial paper was 15 days. (e) Duke Energy includes $1,798 million in purchase accounting adjustments related to the merger with Progress Energy. (f) Duke Energy includes $59 million in purchase accounting adjustments primarily related to the merger with Progress Energy. (g) Refer to Note 17 for additional information on amounts from consolidated VIEs.
Schedule of Maturities of Long-term Debt	The following table shows the annual maturities of long-term debt for the next five years and thereafter. Amounts presented exclude short-term notes payable and commercial paper and money pool borrowings for the Subsidiary Registrants. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy (a) Carolinas Energy Progress Florida Ohio Indiana 2017 $ 2,319 $ 116 $ 778 $ 452 $ 326 $ 1 $ 3 2018 3,466 1,629 559 — 561 3 3 2019 3,316 5 1,992 902 292 551 63 2020 2,112 755 469 152 319 25 653 2021 3,699 501 1,473 602 372 49 70 Thereafter 31,090 6,597 12,270 4,903 4,255 1,255 2,994 Total long-term debt, including current maturities $ 46,002 $ 9,603 $ 17,541 $ 7,011 $ 6,125 $ 1,884 $ 3,786 (a) Excludes $1,893 million in purchase accounting adjustments related to the Progress Energy merger and the Piedmont acquisition.
Schedule of Long-term Debt Instruments	The following tables summarize significant debt issuances (in millions). Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Unsecured Debt April 2016 (a) April 2023 2.875 % $ 350 $ 350 $ — $ — $ — $ — $ — August 2016 September 2021 1.800 % 750 750 — — — — — August 2016 September 2026 2.650 % 1,500 1,500 — — — — — August 2016 September 2046 3.750 % 1,500 1,500 — — — — — Secured Debt June 2016 (b) March 2020 1.196 % 183 — — — 183 — — June 2016 (b) September 2022 1.731 % 150 — — — 150 — — June 2016 (b) September 2029 2.538 % 436 — — — 436 — — June 2016 (b) March 2033 2.858 % 250 — — — 250 — — June 2016 (b) September 2036 3.112 % 275 — — — 275 — — August 2016 June 2034 2.747 % 228 — — — — — — August 2016 June 2020 2.747 % 105 — — — — — — First Mortgage Bonds March 2016 (c) March 2023 2.500 % 500 — 500 — — — — March 2016 (c) March 2046 3.875 % 500 — 500 — — — — May 2016 (d) May 2046 3.750 % 500 — — — — — 500 June 2016 (c) June 2046 3.700 % 250 — — — — 250 — September 2016 (e) October 2046 3.400 % 600 — — — 600 — — September 2016 (c) October 2046 3.700 % 450 — — 450 — — — November 2016 (f) December 2026 2.950 % 600 — 600 — — — — Total issuances $ 9,127 $ 4,100 $ 1,600 $ 450 $ 1,894 $ 250 $ 500 (a) Proceeds were used to pay down outstanding commercial paper and for general corporate purposes. (b) The nuclear asset recovery bonds are sequential pay amortizing bonds. The maturity date above represents the scheduled final maturity date for the bonds. (c) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. (d) Proceeds were used to repay $325 million of unsecured debt due June 2016, $150 million of first mortgage bonds due July 2016 and for general corporate purposes. (e) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance, to repay short-term borrowings under the intercompany money pool borrowing arrangement and for general corporate purposes. (f) Proceeds were used to repay at maturity $350 million aggregate principal amount of certain bonds due December 2016, as well as to fund capital expenditures for ongoing construction and capital maintenance and for general corporate purposes. Year Ended December 31, 2015 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Unsecured Debt November 2015 (a)(b) April 2024 3.750 % $ 400 $ 400 $ — $ — November 2015 (a)(b) December 2045 4.800 % 600 600 — — First Mortgage Bonds March 2015 (c) June 2045 3.750 % 500 — 500 — August 2015 (a)(d) August 2025 3.250 % 500 — — 500 August 2015 (a)(d) August 2045 4.200 % 700 — — 700 Total issuances $ 2,700 $ 1,000 $ 500 $ 1,200 (a) Proceeds were used to repay short-term money pool and commercial paper borrowing issued to fund a portion of the NCEMPA acquisition, see Note 2 for further information. (b) Proceeds were used to refinance at maturity $300 million of unsecured notes at Progress Energy due January 2016. (c) Proceeds were used to redeem at maturity $500 million of first mortgage bonds due October 2015. (d) Proceeds were used to refinance at maturity $400 million of first mortgage bonds due December 2015.
Schedule Of Line Of Credit Facilities	December 31, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (a) (Parent) Carolinas Progress Florida Ohio Indiana Facility size (b) $ 8,350 $ 3,400 $ 1,100 $ 1,000 $ 950 $ 450 $ 600 Reduction to backstop issuances Commercial paper (c) (2,022 ) (977 ) (300 ) (150 ) (84 ) (31 ) (150 ) Outstanding letters of credit (78 ) (69 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 5,634 $ 2,354 $ 511 $ 598 $ 865 $ 419 $ 369 (a) Includes amounts related to Piedmont's $850 million credit facility. (b) Represents the sublimit of each borrower. (c) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Consolidated Balance Sheets.

Guarantees and Indemnificatio42

Guarantees and Indemnifications (Tables)	12 Months Ended
	Dec. 31, 2016
Guarantor Obligations [Line Items]
Schedule of Guarantor Obligations	The following table includes the liabilities recognized for the guarantees discussed above. These amounts are primarily recorded in Other within Deferred Credits and other Liabilities on the Consolidated Balance Sheets. As current estimates change, additional losses related to guarantees and indemnifications to third parties, which could be material, may be recorded by the Duke Energy Registrants in the future. December 31, (in millions) 2016 2015 Duke Energy $ 13 $ 21 Progress Energy — 7 Duke Energy Florida — 7

Joint Ownership of Generating43

Joint Ownership of Generating and Transmission Facilities (Tables)	12 Months Ended
	Dec. 31, 2016
Jointly Owned Utility Plant Interests [Line Items]
Schedule Joint Ownership of Generating and Transmission Facilities	The following table presents the Duke Energy Registrants' interest of jointly owned plant or facilities and amounts included on the Consolidated Balance Sheets. All facilities are operated by the Duke Energy Registrants and are included in the Electric Utilities and Infrastructure segment. December 31, 2016 Construction Ownership Property, Plant Accumulated Work in (in millions except for ownership interest) Interest and Equipment Depreciation Progress Duke Energy Carolinas Catawba Nuclear Station (units 1 and 2) (a) 19.25 % $ 954 $ 612 $ 12 Duke Energy Ohio Transmission facilities (b) Various 90 60 1 Duke Energy Indiana Gibson Station (unit 5) (c) 50.05 % 333 157 11 Vermillion Generating Station (d) 62.5 % 154 111 — Transmission and local facilities (c) Various 4,315 1,715 — (a) Jointly owned with North Carolina Municipal Power Agency Number 1, NCEMC and Piedmont Municipal Power Agency. (b) Jointly owned with America Electric Power Generation Resources and The Dayton Power and Light Company. (c) Jointly owned with Wabash Valley Power Association, Inc. (WVPA) and Indiana Municipal Power Agency. (d) Jointly owned with WVPA.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2016
Asset Retirement Obligation [Abstract]
Schedule of Asset Retirement Obligations by Category	The following table presents the AROs recorded on the Consolidated Balance Sheets. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Decommissioning of Nuclear Power Facilities (a) $ 5,204 $ 1,834 $ 3,172 $ 2,454 $ 717 $ — $ — Closure of Ash Impoundments 5,150 2,032 2,228 2,209 19 43 847 Other (b) 257 29 75 34 42 34 19 Total asset retirement obligation $ 10,611 $ 3,895 $ 5,475 $ 4,697 $ 778 $ 77 $ 866 Less: current portion 411 222 189 189 — — — Total noncurrent asset retirement obligation $ 10,200 $ 3,673 $ 5,286 $ 4,508 $ 778 $ 77 $ 866 (a) The Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy. (b) Primarily includes obligations related to asbestos removal and the closure of certain landfills at fossil generation facilities. Duke Energy Ohio also includes AROs related to the retirement of natural gas mains and services. Duke Energy includes AROs related to the removal of renewable energy generation assets and Piedmont's underground natural gas mains and services.
Public Utilities General Disclosures	The following table presents the fair value of NDTF assets legally restricted for purposes of settling AROs associated with nuclear decommissioning. Duke Energy Florida is actively decommissioning Crystal River Unit 3 and was granted an exemption from the NRC which allows for use of the NDTF for all aspects of nuclear decommissioning. Therefore, the entire balance of Duke Energy Florida's NDTF may be applied toward license termination, spent fuel and site restoration costs incurred to decommission Crystal River Unit 3. December 31, (in millions) 2016 2015 Duke Energy $ 5,099 $ 4,670 Duke Energy Carolinas 2,882 2,686 Duke Energy Progress 2,217 1,984 The following table summarizes information about the most recent site-specific nuclear decommissioning cost studies. Decommissioning costs in the table below are presented in dollars of the year of the cost study and include costs to decommission plant components not subject to radioactive contamination. Annual Funding Decommissioning (in millions) Requirement (a) Costs (a)(b) Year of Cost Study Duke Energy $ 14 $ 8,150 2013 and 2014 Duke Energy Carolinas — 3,420 2013 Duke Energy Progress 14 3,550 2014 Duke Energy Florida — 1,180 2013 (a) Amounts for Progress Energy equal the sum of Duke Energy Progress and Duke Energy Florida. (b) Amounts include the Subsidiary Registrant's ownership interest in jointly owned reactors. Other joint owners are responsible for decommissioning costs related to their interest in the reactors. The following table includes the current expiration of nuclear operating licenses. Unit Year of Expiration Duke Energy Carolinas Catawba Units 1 and 2 2043 McGuire Unit 1 2041 McGuire Unit 2 2043 Oconee Units 1 and 2 2033 Oconee Unit 3 2034 Duke Energy Progress Brunswick Unit 1 2036 Brunswick Unit 2 2034 Harris 2046 Robinson 2030
Rollforward Schedule of Asset Retirement Obligations	The following table presents changes in the liability associated with AROs. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2014 $ 8,464 $ 3,428 $ 4,711 $ 3,905 $ 806 $ 27 $ 32 Acquisitions (a) 226 — 226 204 23 — — Accretion expense (b) 380 165 203 169 34 4 15 Liabilities settled (c) (422 ) (200 ) (195 ) (125 ) (70 ) (4 ) (23 ) Liabilities incurred in the current year (d) 1,016 178 282 282 — 116 418 Revisions in estimates of cash flows 585 347 142 132 9 (18 ) 83 Balance at December 31, 2015 10,249 3,918 5,369 4,567 802 125 525 Acquisitions 22 — 2 — 2 — — Accretion expense (b) 400 187 230 194 35 5 24 Liabilities settled (c) (613 ) (287 ) (272 ) (212 ) (60 ) (5 ) (49 ) Liabilities incurred in the current year 51 — 3 3 — — 29 Revisions in estimates of cash flows 502 77 143 145 (1 ) (48 ) 337 Balance at December 31, 2016 $ 10,611 $ 3,895 $ 5,475 $ 4,697 $ 778 $ 77 $ 866 (a) Duke Energy Progress amount relates to the NCEMPA acquisition. See Note 2 for additional information. (b) Substantially all accretion expense for the years ended December 31, 2016 and 2015 relates to Duke Energy’s regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (c) Amounts primarily relate to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3. (d) Amounts primarily relate to AROs recorded as a result of the EPA's rule for disposal of CCR.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Public Utility, Property, Plant and Equipment [Line Items]
Schedule Of Property, Plant And Equipment	The composite weighted average depreciation rates, excluding nuclear fuel, are included in the table that follows. Years Ended December 31, 2016 2015 2014 Duke Energy 2.8 % 2.9 % 2.8 % Duke Energy Carolinas 2.8 % 2.8 % 2.7 % Progress Energy 2.7 % 2.6 % 2.5 % Duke Energy Progress 2.6 % 2.6 % 2.5 % Duke Energy Florida 2.8 % 2.7 % 2.7 % Duke Energy Ohio 2.6 % 2.7 % 2.3 % Duke Energy Indiana 3.1 % 3.0 % 3.0 % The following tables summarize the property, plant and equipment for Duke Energy and its subsidiary registrants. December 31, 2016 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,501 $ 432 $ 735 $ 393 $ 342 $ 150 $ 106 Plant – Regulated Electric generation, distribution and transmission 8 - 100 89,864 34,515 37,596 23,683 13,913 4,593 13,160 Natural gas transmission and distribution 12 - 67 7,738 — — — — 2,456 — Other buildings and improvements 15 - 100 1,692 502 634 293 341 211 197 Plant – Nonregulated Electric generation, distribution and transmission 5 - 30 4,298 — — — — — — Other buildings and improvements 25 - 35 421 — — — — — — Nuclear fuel 3,572 2,092 1,480 1,480 — — — Equipment 3 - 38 1,941 358 505 378 127 338 156 Construction in process 6,186 2,324 2,708 1,329 1,379 206 396 Other 5 - 40 4,184 904 1,206 863 332 172 226 Total property, plant and equipment (a)(d) 121,397 41,127 44,864 28,419 16,434 8,126 14,241 Total accumulated depreciation – regulated (b)(c)(d) (37,831 ) (14,365 ) (15,212 ) (10,561 ) (4,644 ) (2,579 ) (4,317 ) Total accumulated depreciation – nonregulated (c)(d) (1,575 ) — — — — — — Generation facilities to be retired, net 529 — 529 529 — — — Total net property, plant and equipment $ 82,520 $ 26,762 $ 30,181 $ 18,387 $ 11,790 $ 5,547 $ 9,924 (a) Includes capitalized leases of $1,355 million , $40 million , $288 million , $142 million , $146 million , $81 million and $35 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily within Plant – Regulated. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $99 million , $9 million and $90 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,922 million , $1,192 million , $730 million and $730 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $50 million , $9 million , $19 million and $8 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,591 million and accumulated depreciation of consolidated VIEs of $411 million at Duke Energy. December 31, 2015 Estimated Useful Duke Duke Duke Duke Duke Life Duke Energy Progress Energy Energy Energy Energy (in millions) (Years) Energy Carolinas Energy Progress Florida Ohio Indiana Land $ 1,391 $ 407 $ 719 $ 392 $ 327 $ 118 $ 108 Plant – Regulated Electric generation, distribution and transmission 8 - 100 87,593 33,623 36,422 22,888 13,534 4,429 13,118 Natural gas transmission and distribution 12 - 67 2,322 — — — — 2,322 — Other buildings and improvements 15 - 100 1,480 477 621 294 322 204 179 Plant – Nonregulated Electric generation, distribution and transmission 1 - 30 3,348 — — — — — — Other buildings and improvements 25 - 35 410 — — — — — — Nuclear fuel 3,194 1,827 1,367 1,367 — — — Equipment 3 - 38 1,736 368 530 398 132 344 173 Construction in process 4,485 1,860 1,827 1,118 709 180 214 Other 5 - 60 4,008 836 1,180 856 319 153 215 Total property, plant and equipment (a)(d) 109,967 39,398 42,666 27,313 15,343 7,750 14,007 Total accumulated depreciation – regulated (b)(c)(d) (35,367 ) (13,521 ) (14,867 ) (10,141 ) (4,720 ) (2,507 ) (4,484 ) Total accumulated depreciation – nonregulated (c)(d) (1,369 ) — — — — — — Generation facilities to be retired, net 548 — 548 548 — — — Total net property, plant and equipment $ 73,779 $ 25,877 $ 28,347 $ 17,720 $ 10,623 $ 5,243 $ 9,523 (a) Includes capitalized leases of $1,465 million , $40 million , $302 million , $144 million , $158 million , $96 million and $39 million at Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana, respectively, primarily in regulated plant. The Progress Energy, Duke Energy Progress and Duke Energy Florida amounts are net of $85 million , $7 million and $78 million , respectively, of accumulated amortization of capitalized leases. (b) Includes $1,621 million , $976 million , $645 million and $645 million of accumulated amortization of nuclear fuel at Duke Energy, Duke Energy Carolinas, Progress Energy and Duke Energy Progress, respectively. (c) Includes accumulated amortization of capitalized leases of $57 million , $11 million , $27 million and $7 million at Duke Energy, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana, respectively. (d) Includes gross property, plant and equipment cost of consolidated VIEs of $2,033 million and accumulated depreciation of consolidated VIEs of $327 million at Duke Energy.
Schedule Of Capitalized Interest	The following table presents capitalized interest, which includes the debt component of AFUDC. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 100 $ 98 $ 75 Duke Energy Carolinas 38 38 38 Progress Energy 31 24 11 Duke Energy Progress 17 20 10 Duke Energy Florida 14 4 1 Duke Energy Ohio 8 10 10 Duke Energy Indiana 7 6 6

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill [Line Items]
Goodwill By Reportable Operating Segment	The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill at December 31, 2015 $ 15,656 $ 294 $ 122 $ 16,072 Piedmont Acquisition (a) 1,723 1,630 — 3,353 Goodwill at December 31, 2016 $ 17,379 $ 1,924 $ 122 $ 19,425 (a) Refer to Note 2 for more information on the purchase accounting related to the acquisition of Piedmont.
Schedule of Intangible Assets	The following tables show the carrying amount and accumulated amortization of intangible assets included in Other within Investments and Other Assets on the Consolidated Balance Sheets of the Duke Energy Registrants at December 31, 2016 and 2015 . December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Emission allowances $ 19 $ 1 $ 6 $ 2 $ 4 $ — $ 13 Renewable energy certificates 125 36 84 84 — 4 — Gas, coal and power contracts 24 — — — — — 24 Renewable operating and development projects 97 — — — — — — Other 6 — — — — — — Total gross carrying amounts 271 37 90 86 4 4 37 Accumulated amortization – gas, coal and power contracts (17 ) — — — — — (17 ) Accumulated amortization – renewable operating and development projects (23 ) — — — — — — Accumulated amortization – other (5 ) — — — — — — Total accumulated amortization (45 ) — — — — — (17 ) Total intangible assets, net $ 226 $ 37 $ 90 $ 86 $ 4 $ 4 $ 20 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Emission allowances $ 20 $ 1 $ 6 $ 2 $ 4 $ — $ 14 Renewable energy certificates 116 30 80 80 — 5 — Gas, coal and power contracts 24 — — — — — 24 Renewable operating and development projects 115 — — — — — — Other 2 — — — — — — Total gross carrying amounts 277 31 86 82 4 5 38 Accumulated amortization – gas, coal and power contracts (16 ) — — — — — (16 ) Accumulated amortization – renewable operating and development projects (18 ) — — — — — — Accumulated amortization – other (1 ) — — — — — — Total accumulated amortization (35 ) — — — — — (16 ) Total intangible assets, net $ 242 $ 31 $ 86 $ 82 $ 4 $ 5 $ 22
Schedule of Amortization Expense	The following table presents amortization expense for gas, coal and power contracts, renewable operating projects and other intangible assets. December 31, (in millions) 2016 2015 2014 Duke Energy $ 6 $ 5 $ 6 Duke Energy Ohio — — 2 Duke Energy Indiana 1 1 1
Schedule of Expected Amortization Expense	The amortization amounts discussed below are estimates and actual amounts may differ from these estimates due to such factors as changes in consumption patterns, sales or impairments of emission allowances or other intangible assets, delays in the in-service dates of renewable assets, additional intangible acquisitions and other events. (in millions) 2017 2018 2019 2020 2021 Duke Energy $ 5 $ 5 $ 5 $ 5 $ 5 Duke Energy Indiana 2 2 2 2 2

Investments in Unconsolidated47

Investments in Unconsolidated Affiliates (Tables)	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investments in Equity Method Unconsolidated Affiliates	The table below outlines Duke Energy's ownership interests in natural gas pipeline companies and natural gas storage facilities. See Notes 4 and 17 for more information. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest 2016 2015 Pipeline Investments Atlantic Coast Pipeline, LLC 47 % $ 265 $ 52 Sabal Trail Transmission, LLC 7.5 % 140 61 Constitution Pipeline, LLC 24 % 82 — Cardinal Pipeline Company, LLC 21.49 % 16 — Storage Facilities Pine Needle LNG Company, LLC 45 % 16 — Hardy Storage Company, LLC 50 % 47 — Total Investments $ 566 $ 113 The following table presents Duke Energy’s investments in unconsolidated affiliates accounted for under the equity method, as well as the respective equity in earnings, by segment. Years Ended December 31, 2016 2015 2014 Equity in Equity in Equity in (in millions) Investments earnings Investments earnings earnings Electric Utilities and Infrastructure $ 93 $ 5 $ 57 $ (2 ) $ (1 ) Gas Utilities and Infrastructure 566 19 113 1 — Commercial Renewables 185 (82 ) 265 (6 ) 8 Other 81 43 64 76 123 Total $ 925 $ (15 ) $ 499 $ 69 $ 130

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Progress Energy [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 831 $ 914 $ 851 Indemnification coverages (b) 22 24 21 JDA revenue (c) 38 51 133 JDA expense (c) 156 183 198 Progress Energy Corporate governance and shared service expenses (a) $ 710 $ 712 $ 732 Indemnification coverages (b) 35 38 33 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Progress Corporate governance and shared service expenses (a) $ 397 $ 403 $ 386 Indemnification coverages (b) 14 16 17 JDA revenue (c) 156 183 198 JDA expense (c) 38 51 133 Intercompany natural gas purchases (d) 19 — — Duke Energy Florida Corporate governance and shared service expenses (a) $ 313 $ 309 $ 346 Indemnification coverages (b) 21 22 16 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 356 $ 342 $ 316 Indemnification coverages (b) 5 6 13 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 366 $ 349 $ 384 Indemnification coverages (b) 8 9 11 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income. (d) Duke Energy Progress purchases natural gas from Piedmont to supply electric generation facilities. These expenses are recorded in Fuel used in electric generation and purchased power on the Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable	Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables for the subsidiary registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — Intercompany income tax payable — 37 90 — 1 3 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The following tables show notional amounts of outstanding derivatives related to interest rate risk. December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 750 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,677 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 497 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,324 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $750 million and $497 million at December 31, 2016 and 2015 , respectively. The December 31, 2016, amount includes interest rate swaps related to solar facilities financing with an outstanding notional amount of $300 million , including $81 million of four-year swaps and $219 million of 18-year swaps. See note 6 for additional information related to the solar facilities financing. The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 147 — — — — — 147 Natural gas (millions of dekatherms) (a) 890 91 269 118 151 — 1 (a) Amounts at Duke Energy increased 529 million dekatherms due to the acquisition of Piedmont in 2016. December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of dekatherms) 398 66 332 117 215 — —
Location and Fair Value of Derivatives Recognized in the Consolidated Balance Sheets	The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 108 $ 23 $ 61 $ 35 $ 26 $ 4 $ 16 Noncurrent 32 10 21 10 11 1 — Total Derivative Assets – Commodity Contracts $ 140 $ 33 $ 82 $ 45 $ 37 $ 5 $ 16 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 19 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 3 — 3 1 2 — — Total Derivative Assets – Interest Rate Contracts $ 22 $ — $ 3 $ 1 $ 2 $ — $ — Total Derivative Assets $ 162 $ 33 $ 85 $ 46 $ 39 $ 5 $ 16 Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 43 $ — $ 12 $ — $ 12 $ — $ 2 Noncurrent 166 1 7 1 — — — Total Derivative Liabilities – Commodity Contracts $ 209 $ 1 $ 19 $ 1 $ 12 $ — $ 2 Interest Rate Contracts Designated as Hedging Instruments Current $ 8 $ — $ — $ — $ — $ — $ — Noncurrent 8 — — — — — — Not Designated as Hedging Instruments Current 1 — — — — 1 — Noncurrent 26 15 6 6 — 5 — Total Derivative Liabilities – Interest Rate Contracts $ 43 $ 15 $ 6 $ 6 $ — $ 6 $ — Total Derivative Liabilities $ 252 $ 16 $ 25 $ 7 $ 12 $ 6 $ 2 Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 3 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 9 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 25 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 9 $ — $ — $ — $ — $ — $ — Noncurrent 13 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 41 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 397 $ 45 $ 322 $ 98 $ 216 $ 7 $ —
Offsetting Assets	The following tables present the line items on the Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 111 $ 23 $ 64 $ 36 $ 28 $ 4 $ 16 Gross amounts offset (11 ) — (11 ) — (11 ) — — Net amounts presented in Current Assets: Other $ 100 $ 23 $ 53 $ 36 $ 17 $ 4 $ 16 Noncurrent Gross amounts recognized $ 51 $ 10 $ 21 $ 10 $ 11 $ 1 $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Investments and Other Assets: Other $ 49 $ 9 $ 20 $ 9 $ 11 $ 1 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 7 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 3 $ — $ — $ — $ — $ — $ —
Offsetting Liabilities	Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 269 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 247 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 128 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 112 $ 13 $ 82 $ 21 $ 56 $ 6 $ — Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 52 $ — $ 12 $ — $ 12 $ 1 $ 2 Gross amounts offset (11 ) — (11 ) — (11 ) — — Net amounts presented in Current Liabilities: Other $ 41 $ — $ 1 $ — $ 1 $ 1 $ 2 Noncurrent Gross amounts recognized $ 200 $ 16 $ 13 $ 7 $ — $ 5 $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 198 $ 15 $ 12 $ 6 $ — $ 5 $ —
Derivative Contracts with Contingent Credit Features	The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio and Duke Energy Indiana were not material. December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 34 $ 16 $ 18 $ 6 $ 12 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 34 16 18 6 12 December 31, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement. At December 31, 2015, receivables of $30 million at Duke Energy Florida related to the right to reclaim cash collateral under master netting arrangements were offset against net derivative positions on the Consolidated Balance Sheets of Duke Energy, Progress Energy and Duke Energy Florida.

Investments in Debt and Equit50

Investments in Debt and Equity Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 111 $ — $ — $ 179 Equity securities 2,092 54 4,106 1,823 58 3,590 Corporate debt securities 10 8 528 7 8 432 Municipal bonds 3 10 331 5 1 185 U.S. government bonds 10 8 984 11 5 1,254 Other debt securities — 3 124 — 4 177 Total NDTF $ 2,115 $ 83 $ 6,184 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 25 $ — $ — $ 29 Equity securities 38 — 104 32 1 95 Corporate debt securities 1 1 66 1 3 92 Municipal bonds 2 1 82 3 1 74 U.S. government bonds — 1 51 — — 45 Other debt securities — 2 42 — 2 62 Total Other Investments (b) $ 41 $ 5 $ 370 $ 36 $ 7 $ 397 Total Investments $ 2,156 $ 88 $ 6,554 $ 1,882 $ 83 $ 6,214 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 94 Due after one through five years 653 Due after five through 10 years 515 Due after 10 years 946 Total $ 2,208
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 246 $ 193 $ 271 Realized losses 187 98 105
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 18 $ — $ — $ 34 Equity securities 1,157 28 2,245 1,021 27 2,094 Corporate debt securities 5 6 354 3 5 292 Municipal bonds 1 2 67 1 — 33 U.S. government bonds 2 5 458 3 3 438 Other debt securities — 3 116 — 4 147 Total NDTF $ 1,165 $ 44 $ 3,258 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (b) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,165 $ 45 $ 3,261 $ 1,028 $ 40 $ 3,041 (a) Substantially all these amounts represent OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 3 Due after one through five years 230 Due after five through 10 years 260 Due after 10 years 505 Total $ 998
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 157 $ 158 $ 109 Realized losses 121 83 93
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 93 $ — $ — $ 145 Equity securities 935 26 1,861 802 31 1,496 Corporate debt securities 5 2 174 4 3 140 Municipal bonds 2 8 264 4 1 152 U.S. government bonds 8 3 526 8 2 816 Other debt securities — — 8 — — 30 Total NDTF $ 950 $ 39 $ 2,926 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 21 $ — $ — $ 18 Municipal bonds 2 — 44 3 — 45 Total Other Investments (b) $ 2 $ — $ 65 $ 3 $ — $ 63 Total Investments $ 952 $ 39 $ 2,991 $ 821 $ 37 $ 2,842 (a) Substantially all these amounts represent OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 84 Due after one through five years 347 Due after five through 10 years 187 Due after 10 years 398 Total $ 1,016
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 84 $ 33 $ 157 Realized losses 64 13 11
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 45 $ — $ — $ 110 Equity securities 704 21 1,505 596 25 1,178 Corporate debt securities 4 1 120 3 2 96 Municipal bonds 2 8 263 4 1 150 U.S. government bonds 5 2 275 6 2 486 Other debt securities — — 5 — — 18 Total NDTF $ 715 $ 32 $ 2,213 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (b) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 715 $ 32 $ 2,214 $ 609 $ 30 $ 2,039 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 28 Due after one through five years 190 Due after five through 10 years 142 Due after 10 years 303 Total $ 663
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 71 $ 26 $ 19 Realized losses 55 11 5
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value NDTF Cash and cash equivalents $ — $ — $ 48 $ — $ — $ 35 Equity securities 231 5 356 206 6 318 Corporate debt securities 1 1 54 1 1 44 Municipal bonds — — 1 — — 2 U.S. government bonds 3 1 251 2 — 330 Other debt securities — — 3 — — 12 Total NDTF (b) $ 235 $ 7 $ 713 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 4 $ — $ — $ 6 Municipal bonds 2 — 44 3 — 45 Total Other Investments (c) $ 2 $ — $ 48 $ 3 $ — $ 51 Total Investments $ 237 $ 7 $ 761 $ 212 $ 7 $ 792 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) The decrease in estimated fair value of the NDTF as of December 31, 2016 , is primarily due to reimbursements from the NDTF for costs related to ongoing decommissioning activity of Crystal River Unit 3. (c) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 56 Due after one through five years 157 Due after five through 10 years 45 Due after 10 years 95 Total $ 353
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Years Ended December 31, (in millions) 2016 2015 2014 Realized gains $ 13 $ 7 $ 138 Realized losses 9 2 5
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Investments	The following table presents the estimated fair value of investments in available-for-sale securities. December 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Unrealized Unrealized Holding Holding Estimated Holding Holding Estimated (in millions) Gains Losses (a) Fair Value Gains Losses (a) Fair Value Other Investments Cash and cash equivalents $ — $ — $ — $ — $ — $ 2 Equity securities 33 — 79 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds — 1 28 — 1 26 U.S. government bonds — — 1 — — — Total Other Investments (b) $ 33 $ 1 $ 110 $ 27 $ 1 $ 101 Total Investments $ 33 $ 1 $ 110 $ 27 $ 1 $ 101 (a) Substantially all these amounts are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (b) These amounts are recorded in Other within Investments and Other Assets on the Consolidated Balance Sheets.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) December 31, 2016 Due in one year or less $ 3 Due after one through five years 13 Due after five through 10 years 9 Due after 10 years 6 Total $ 31

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 4,106 $ 4,029 $ — $ — $ 77 Nuclear decommissioning trust fund debt securities 2,078 632 1,446 — — Other trading and available-for-sale equity securities 104 104 — — — Other trading and available-for-sale debt securities 266 75 186 5 — Derivative assets 162 5 136 21 — Total assets 6,716 4,845 1,768 26 77 Derivative liabilities (252 ) (2 ) (63 ) (187 ) — Net assets (liabilities) $ 6,464 $ 4,843 $ 1,705 $ (161 ) $ 77 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 — Derivative assets 25 — 15 10 — Total assets 6,239 4,260 1,792 15 172 Derivative liabilities (397 ) — (397 ) — — Net assets $ 5,842 $ 4,260 $ 1,395 $ 15 $ 172
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues. December 31, 2016 Derivatives (in millions) Investments (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Derivative liability resulting from the acquisition of Piedmont — (187 ) (187 ) Purchases, sales, issuances and settlements: Purchases — 33 33 Settlements — (28 ) (28 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities — 6 6 Balance at end of period $ 5 $ (166 ) $ (161 ) December 31, 2015 Derivatives (in millions) Investments (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains (losses) included in earnings — 21 21 Purchases, sales, issuances and settlements: Purchases — 24 24 Sales — (1 ) (1 ) Settlements — (37 ) (37 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities — 4 4 Balance at end of period $ 5 $ 10 $ 15
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. December 31, 2016 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Natural gas contracts $ (187 ) Discounted cash flow Forward natural gas curves - price per million British thermal unit (MMBtu) $ 2.31 - $ 4.18 Financial Transmission Rights (FTRs) 21 RTO auction pricing FTR price – per megawatt-hour (MWh) (0.83 ) - 9.32 Total Level 3 derivatives $ (166 ) Duke Energy Ohio $ 5 RTO auction pricing FTR price – per MWh $ 0.77 - $ 3.52 Duke Energy Indiana 16 RTO auction pricing FTR price – per MWh (0.83 ) - 9.32 December 31, 2015 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29
Schedule of Long-term debt, including current	The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. December 31, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 47,895 $ 49,161 $ 38,868 $ 41,767 Duke Energy Carolinas 9,603 10,494 8,367 9,156 Progress Energy 17,541 19,107 14,464 15,856 Duke Energy Progress 7,011 7,357 6,518 6,757 Duke Energy Florida 6,125 6,728 4,266 4,908 Duke Energy Ohio 1,884 2,020 1,598 1,724 Duke Energy Indiana 3,786 4,260 3,768 4,219
Duke Energy Carolinas [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 2,245 $ 2,168 $ — $ — $ 77 Nuclear decommissioning trust fund debt securities 1,013 178 835 — — Other available-for-sale debt securities 3 — — 3 — Derivative assets 33 — 33 — — Total assets 3,294 2,346 868 3 77 Derivative liabilities (16 ) — (16 ) — — Net assets $ 3,278 $ 2,346 $ 852 $ 3 $ 77 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not Categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — — Other available-for-sale debt securities 3 — — 3 — Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172
Progress Energy [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,861 $ 1,861 $ — Nuclear decommissioning trust fund debt securities 1,065 454 611 Other available-for-sale debt securities 65 21 44 Derivative assets 85 — 85 Total assets 3,076 2,336 740 Derivative liabilities (25 ) — (25 ) Net assets $ 3,051 $ 2,336 $ 715 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591
Duke Energy Progress [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,505 $ 1,505 $ — Nuclear decommissioning trust fund debt securities and other 708 207 501 Other available-for-sale debt securities and other 1 1 — Derivative assets 46 — 46 Total assets 2,260 1,713 547 Derivative liabilities (7 ) — (7 ) Net assets $ 2,253 $ 1,713 $ 540 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623
Duke Energy Florida [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 356 $ 356 $ — Nuclear decommissioning trust fund debt securities and other 357 247 110 Other available-for-sale debt securities and other 48 4 44 Derivative assets 39 — 39 Total assets 800 607 193 Derivative liabilities (12 ) — (12 ) Net assets $ 788 $ 607 $ 181 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 )
Duke Energy Ohio [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which are disclosed in Note 14 . December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 5 $ — $ — $ 5 Derivative liabilities (6 ) — (6 ) — Net (liabilities) assets $ (1 ) $ — $ (6 ) $ 5 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains (losses) included in earnings — 21 Purchases, sales, issuances and settlements: Purchases 5 5 Settlements (5 ) (5 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities 2 — Balance at end of period $ 5 $ 3
Duke Energy Indiana [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 14 . See Note 15 for additional information related to investments by major security type. December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 79 $ 79 $ — $ — Other available-for-sale debt securities and other 31 — 31 — Derivative assets 16 — — 16 Total assets 126 79 31 16 Derivative liabilities (2 ) (2 ) — — Net assets $ 124 $ 77 $ 31 $ 16 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Years Ended December 31, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Purchases, sales, issuances and settlements: Purchases 29 19 Settlements (24 ) (30 ) Total gains included on the Consolidated Balance Sheet as regulatory assets or liabilities 4 4 Balance at end of period $ 16 $ 7

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2016
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following table outlines amounts and expiration dates of the credit facilities described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount (in millions) $ 325 $ 425 $ 300 $ 225 Amounts borrowed at December 31, 2016 325 425 300 225 Amounts borrowed at December 31, 2015 325 425 254 225
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following tables summarize the impact of non-consolidated VIEs on the Consolidated Balance Sheets. December 31, 2016 Duke Energy Duke Duke Pipeline Commercial Energy Energy (in millions) Investments Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 82 $ 101 Investments in equity method unconsolidated affiliates 487 174 90 751 — — Investments and other assets 12 — — 12 — — Total assets $ 499 $ 174 $ 90 $ 763 $ 82 $ 101 Other current liabilities — — 3 3 — — Deferred credits and other liabilities — — 13 13 — — Total liabilities $ — $ — $ 16 $ 16 $ — $ — Net assets (liabilities) $ 499 $ 174 $ 74 $ 747 $ 82 $ 101 December 31, 2015 Duke Energy Duke Duke Pipeline Commercial Energy Energy (in millions) Investments Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 113 235 39 387 — Total assets $ 113 $ 235 $ 39 $ 387 $ 47 $ 60 Other current liabilities — — 3 3 — — Deferred credits and other liabilities — — 14 14 — — Total liabilities $ — $ — $ 17 $ 17 $ — $ — Net assets $ 113 $ 235 $ 22 $ 370 $ 47 $ 60
Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2016 2015 2016 2015 Anticipated credit loss ratio 0.5 % 0.6 % 0.3 % 0.3 % Discount rate 1.5 % 1.2 % 1.5 % 1.2 % Receivable turnover rate 13.3 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) 2016 2015 2016 2015 Receivables sold $ 267 $ 233 $ 306 $ 260 Less: Retained interests 82 47 101 60 Net receivables sold $ 185 $ 186 $ 205 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Years Ended December 31, Years Ended December 31, (in millions) 2016 2015 2014 2016 2015 2014 Sales Receivables sold $ 1,926 $ 1,963 $ 2,246 $ 2,635 $ 2,627 $ 2,913 Loss recognized on sale 9 9 11 11 11 11 Cash Flows Cash proceeds from receivables sold 1,882 1,995 2,261 2,583 2,670 2,932 Collection fees received 1 1 1 1 1 1 Return received on retained interests 2 3 4 5 5 6
DEFPF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the impact of DEFPF on Duke Energy Florida's Consolidated Balance Sheets. (in millions) December 31, 2016 Receivables of VIEs $ 6 Regulatory Assets: Current 50 Current Assets: Other 53 Regulatory Assets and Deferred Debits: Regulatory assets 1,142 Current Liabilities: Other 17 Current maturities of long-term debt 62 Long-Term Debt 1,217
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	Duke Energy consolidates the entities as it is responsible for all of these decisions. The table below presents material balances reported on Duke Energy's Consolidated Balance Sheets related to renewables VIEs. (in millions) December 31, 2016 December 31, 2015 Current Assets: Other $ 223 $ 138 Property, plant and equipment, cost 3,419 2,015 Accumulated depreciation and amortization (453 ) (321 ) Current maturities of long-term debt 198 108 Long-Term Debt 1,097 968 Deferred Credits and Other Liabilities: Deferred income taxes 275 289 Deferred Credits and Other Liabilities: Other 252 33
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule Of Variable Interest Entities	The table below presents Duke Energy's ownership interest and investment balance in in these joint ventures. Investment Amount (in millions) Ownership December 31, December 31, Entity Name Interest (a) 2016 2015 ACP 47 % $ 265 $ 52 Sabal Trail 7.5 % 140 61 Constitution 24 % 82 — Total $ 487 $ 113 (a) The percentages presented reflect Duke Energy's ownership interest as of December 31, 2016. The investment amount presented for ACP as of December 31, 2015, reflects 40 percent ownership interest prior to acquiring an additional 7 percent as a result of the Piedmont acquisition. See Notes 2 and 4 for additional information related to the Piedmont acquisition and increased ownership of ACP.

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common stock outstanding to the diluted weighted average number of common stock outstanding. Years Ended December 31, (in millions, except per share amounts) 2016 2015 2014 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 2,567 $ 2,640 $ 2,529 Weighted average shares outstanding – basic 691 694 707 Weighted average shares outstanding – diluted 691 694 707 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 3.71 3.80 3.58 Diluted $ 3.71 3.80 3.58 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 3.36 3.24 3.15 (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met.

Severance (Tables)

Severance (Tables)	12 Months Ended
	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Schedule of Severance Expense	The following table presents the direct and allocated severance and related expenses recorded by the Duke Energy Registrants. Amounts are included within Operation, maintenance and other on the Consolidated Statements of Operations. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Year Ended December 31, 2016 $ 118 $ 39 $ 40 $ 23 $ 17 $ 3 $ 7 Year Ended December 31, 2015 142 93 36 28 8 2 6
Schedule of Severance Liability	The table below presents the severance liability for past and ongoing severance plans including the plans described above. Amounts for Duke Energy Indiana and Duke Energy Ohio are not material. Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Balance at December 31, 2015 $ 136 $ 78 $ 23 $ 19 $ 4 Provision/Adjustments 110 18 20 11 9 Cash Reductions (167 ) (83 ) (29 ) (24 ) (5 ) Balance at December 31, 2016 $ 79 $ 13 $ 14 $ 6 $ 8

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule Of Total Stock-Based Compensation Expense, net of tax	The following table summarizes the total expense recognized by the Duke Energy Registrants, net of tax, for stock-based compensation. Years Ended December 31, (in millions) 2016 2015 2014 Duke Energy $ 35 $ 38 $ 38 Duke Energy Carolinas 12 14 12 Progress Energy 12 14 14 Duke Energy Progress 7 9 9 Duke Energy Florida 5 5 5 Duke Energy Ohio 2 2 5 Duke Energy Indiana 3 4 3
Schedule Of Stock-Based Compensation Expense	Duke Energy's pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Years Ended December 31, (in millions) 2016 2015 2014 Restricted stock unit awards $ 36 $ 38 $ 39 Performance awards 19 23 22 Pretax stock-based compensation cost $ 55 $ 61 $ 61 Tax benefit associated with stock-based compensation expense $ 20 $ 23 $ 23 Stock-based compensation costs capitalized 2 3 4
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The following table includes information related to restricted stock unit awards. Years Ended December 31, 2016 2015 2014 Shares awarded (in thousands) 684 524 557 Fair value (in millions) $ 52 $ 41 $ 40 The following table summarizes information about restricted stock unit awards outstanding. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2015 953 $ 75 Piedmont transfers in 113 79 Granted 684 75 Vested (525 ) 73 Forfeited (86 ) 76 Outstanding at December 31, 2016 1,139 76 Restricted stock unit awards expected to vest 1,056 76
Schedule of Performance Awards	The following table includes information related to stock-based performance awards. Years Ended December 31, 2016 2015 2014 Shares awarded (in thousands) 675 642 542 Fair value (in millions) $ 25 $ 26 $ 19
Schedule of Share-based Compensation, Stock Options, Activity	The following table summarizes information about stock options outstanding. Weighted Average Stock Options Exercise Price (in thousands) (per share) Outstanding at December 31, 2015 103 $ 69 Exercised (103 ) 69 Outstanding at December 31, 2016 — —
Schedule of Nonvested Performance-based Units Activity	The following table summarizes information about stock-based performance awards outstanding and assumes payout at the maximum level. Weighted Average Shares Grant Date Fair Value (in thousands) (per share) Outstanding at December 31, 2015 1,697 $ 40 Granted 675 38 Vested (544 ) 46 Forfeited (104 ) 38 Outstanding at December 31, 2016 1,724 38 Stock-based performance awards expected to vest 1,199 38
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Exercises	The following table summarizes additional information related to stock options exercised and granted. Years Ended December 31, (in millions) 2016 2015 2014 Intrinsic value of options exercised $ 1 $ 5 $ 6 Tax benefit related to options exercised — 2 2 Cash received from options exercised 7 17 25

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Contributions	Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. The following table includes information related to the Duke Energy Registrants’ contributions to its U.S. qualified defined benefit pension plans. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Anticipated Contributions: 2017 $ 160 $ 45 $ 45 $ 25 $ 20 $ 4 $ 9 Contributions Made: 2016 $ 155 $ 43 $ 43 $ 24 $ 20 $ 5 $ 9 2015 302 91 83 42 40 8 19 2014 — — — — — — —
Employee Savings Plan Matching Contributions	The following table includes pretax employer matching contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ended December 31, 2016 $ 169 $ 57 $ 50 $ 35 $ 15 $ 3 $ 8 2015 159 54 48 34 13 3 7 2014 143 47 43 30 14 3 7
Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value and Allocation of Plan Assets	The following table includes the target asset allocations by asset class at December 31, 2016 and the actual asset allocations for the Duke Energy Master Retirement Trust. Actual Allocation at Target December 31, Allocation (a) 2016 (a) 2015 U.S. equity securities 10 % 11 % 11 % Non-U.S. equity securities 8 % 8 % 8 % Global equity securities 10 % 10 % 10 % Global private equity securities 3 % 2 % 2 % Debt securities 63 % 63 % 63 % Hedge funds 2 % 2 % 2 % Real estate and cash 2 % 2 % 2 % Other global securities 2 % 2 % 2 % Total 100 % 100 % 100 % (a) Excludes Piedmont Pension Assets , which have a targeted asset allocation of 60 percent return-seeking and 40 percent liability hedging fixed-income. Actual asset allocations were 61 percent return-seeking and 39 percent liability hedging fixed-income at December 31, 2016 . The following tables provide the fair value measurement amounts for the Duke Energy Master Retirement Trust qualified pension and other post-retirement assets and Piedmont Pension Assets. December 31, 2016 Total Fair Not (in millions) Value Level 1 Level 2 Level 3 Categorized (b) Equity securities $ 2,472 $ 1,677 $ 27 $ 9 759 Corporate debt securities 4,330 8 4,322 — — Short-term investment funds 476 211 265 — — Partnership interests 157 — — — 157 Hedge funds 232 — — — 232 Real estate limited partnerships 144 17 — — 127 U.S. government securities 734 — 734 — — Guaranteed investment contracts 29 — — 29 — Governments bonds – foreign 32 — 32 — — Cash 17 15 2 — — Government and commercial mortgage backed securities — — — — — Net pending transactions and other investments 32 1 6 — 25 Total assets (a) $ 8,655 $ 1,929 $ 5,388 $ 38 $ 1,300 (a) Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana were allocated approximately 27 percent , 30 percent , 15 percent , 15 percent , 5 percent and 8 percent , respectively, of the Duke Energy Master Retirement Trust and Piedmont Pension assets at December 31, 2016 . Accordingly, all amounts included in the table above are allocable to the Subsidiary Registrants using these percentages. (b) Certain investments are not categorized. These investments are measured based on the fair value of the underlying investments but may not be readily redeemable at that fair value. December 31, 2015 Total Fair Not (in millions) Value Level 1 Level 2 Level 3 Categorized (b) Equity securities $ 2,160 $ 1,470 $ 2 $ — $ 688 Corporate debt securities 4,362 — 4,362 — — Short-term investment funds 404 192 212 — — Partnership interests 185 — — — 185 Hedge funds 210 — — — 210 Real estate limited partnerships 118 — — — 118 U.S. government securities 748 — 748 — — Guaranteed investment contracts 31 — — 31 — Governments bonds – foreign 34 — 34 — — Cash 10 10 — — — Government and commercial mortgage backed securities 9 — 9 — — Net pending transactions and other investments (28 ) (36 ) 8 — — Total assets (a) $ 8,243 $ 1,636 $ 5,375 $ 31 $ 1,201 (a) Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana were allocated approximately 28 percent , 32 percent , 15 percent , 16 percent , 5 percent and 8 percent , respectively, of the Duke Energy Master Retirement Trust assets at December 31, 2015 . Accordingly, all amounts included in the table above are allocable to the Subsidiary Registrants using these percentages. (b) Certain investments are not categorized. These investments are measured based on the fair value of the underlying investments but may not be readily redeemable at that fair value.
Master Trust Level 3 Rollforward	The following table provides a reconciliation of beginning and ending balances of Duke Energy Master Retirement Trust qualified pension and other post-retirement assets and Piedmont Pension Assets at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3). (in millions) 2016 2015 Balance at January 1 $ 31 $ 34 Combination of Piedmont Pension Assets 9 — Sales (2 ) (2 ) Total gains (losses) and other, net — (1 ) Balance at December 31 $ 38 $ 31
Voluntary Employee Beneficiary Association [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value and Allocation of Plan Assets	The following table presents target and actual asset allocations for the OPEB Assets at December 31, 2016 . Actual Allocation at Target December 31, Allocation 2016 2015 U.S. equity securities 38 % 39 % 29 % Real estate 2 % 2 % — % Debt securities 45 % 37 % 28 % Cash 15 % 22 % 43 % Total 100 % 100 % 100 % The following tables provide the fair value measurement amounts for OPEB Assets. December 31, 2016 Total Fair (in millions) Value Level 1 Level 2 Level 3 Cash and cash equivalents $ 14 — $ 14 — Real estate 1 — 1 — Equity securities 26 — 26 — Debt securities 25 — 25 — Total assets $ 66 — $ 66 — December 31, 2015 Total Fair (in millions) Value Level 1 Level 2 Level 3 Cash and cash equivalents $ 18 — $ 18 — Equity securities 12 — 12 — Debt securities 12 — 12 — Total assets $ 42 — $ 42 —
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	Components of Net Periodic Pension Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 147 $ 48 $ 42 $ 24 $ 19 $ 4 $ 9 Interest cost on projected benefit obligation 335 86 106 49 55 19 28 Expected return on plan assets (519 ) (142 ) (168 ) (82 ) (84 ) (27 ) (42 ) Amortization of actuarial loss 134 33 51 23 29 4 11 Amortization of prior service credit (17 ) (8 ) (3 ) (2 ) (1 ) — (1 ) Settlement charge 3 — — — — — — Other 8 2 3 1 1 1 1 Net periodic pension costs (a)(b) $ 91 $ 19 $ 31 $ 13 $ 19 $ 1 $ 6 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 159 $ 50 $ 44 $ 23 $ 20 $ 4 $ 10 Interest cost on projected benefit obligation 324 83 104 48 54 18 27 Expected return on plan assets (516 ) (139 ) (171 ) (79 ) (87 ) (26 ) (42 ) Amortization of actuarial loss 166 39 65 33 31 7 13 Amortization of prior service (credit) cost (15 ) (7 ) (3 ) (2 ) (1 ) — 1 Other 8 2 3 1 1 — 1 Net periodic pension costs (a)(b) $ 126 $ 28 $ 42 $ 24 $ 18 $ 3 $ 10 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 135 $ 41 $ 40 $ 21 $ 20 $ 4 $ 9 Interest cost on projected benefit obligation 344 85 112 54 57 20 29 Expected return on plan assets (511 ) (132 ) (173 ) (85 ) (85 ) (27 ) (41 ) Amortization of actuarial loss 150 36 68 32 32 4 13 Amortization of prior service credit (15 ) (8 ) (3 ) (2 ) (1 ) — — Other 8 2 3 1 1 — 1 Net periodic pension costs (a)(b) $ 111 $ 24 $ 47 $ 21 $ 24 $ 1 $ 11 (a) Duke Energy amounts exclude $8 million , $9 million and $10 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $4 million , $4 million and $5 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006.
Amounts Recognized in AOCI and Regulatory Assets and Liabilities	Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase $ 214 $ 4 $ 34 $ 18 $ 16 $ 2 $ 9 Accumulated other comprehensive loss (income) Deferred income tax expense $ 4 — — — — — — Prior year service credit arising during the year (2 ) — — — — — — Amortization of prior year actuarial losses (7 ) — (1 ) — — — — Net amount recognized in accumulated other comprehensive income $ (5 ) $ — $ (1 ) $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 173 $ 65 $ 18 $ 14 $ 4 $ 14 $ 11 Accumulated other comprehensive (income) loss Deferred income tax expense $ 6 $ — $ 5 $ — $ — $ — $ — Actuarial losses arising during the year 4 — — — — — — Prior year service credit arising during the year 1 — — — — — — Amortization of prior year actuarial losses (11 ) — (4 ) — — — — Transfer with the Midwest Generation Disposal Group 3 — — — — — — Reclassification of actuarial losses to regulatory assets (6 ) — — — — — — Net amount recognized in accumulated other comprehensive income $ (3 ) $ — $ 1 $ — $ — $ — $ —
Reconciliation of Funded Status to Net Amount Recognized	Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 7,727 $ 1,995 $ 2,451 $ 1,143 $ 1,276 $ 453 $ 649 Obligation assumed from acquisition 352 — — — — — — Service cost 147 48 42 24 19 4 9 Interest cost 335 86 106 49 55 19 28 Actuarial loss 307 46 111 52 57 13 41 Transfers — 14 (3 ) (3 ) — (3 ) — Plan amendments (52 ) (3 ) — — — (3 ) (15 ) Benefits paid (679 ) (234 ) (195 ) (107 ) (84 ) (36 ) (54 ) Impact of settlements (6 ) — — — — — — Obligation at measurement date $ 8,131 $ 1,952 $ 2,512 $ 1,158 $ 1,323 $ 447 $ 658 Accumulated Benefit Obligation at measurement date $ 8,006 $ 1,952 $ 2,479 $ 1,158 $ 1,290 $ 436 $ 649 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,136 $ 2,243 $ 2,640 $ 1,284 $ 1,321 $ 433 $ 655 Assets received from acquisition 343 — — — — — — Employer contributions 155 43 43 24 20 5 9 Actual return on plan assets 582 159 190 92 95 29 47 Benefits paid (679 ) (234 ) (195 ) (107 ) (84 ) (36 ) (54 ) Impact of settlements (6 ) — — — — — — Transfers — 14 (3 ) (3 ) — (3 ) — Plan assets at measurement date $ 8,531 $ 2,225 $ 2,675 $ 1,290 $ 1,352 $ 428 $ 657 Funded status of plan $ 400 $ 273 $ 163 $ 132 $ 29 $ (19 ) $ (1 ) Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 8,107 $ 2,053 $ 2,557 $ 1,187 $ 1,335 $ 469 $ 673 Obligation transferred with Midwest Generation Disposal Group (83 ) — — — — — — Service cost 159 50 44 23 20 4 10 Interest cost 324 83 104 48 54 18 27 Actuarial gain (241 ) (53 ) (111 ) (46 ) (62 ) (9 ) (15 ) Transfers — 8 4 7 (3 ) 8 — Plan amendments (6 ) — — — — — (4 ) Benefits paid (533 ) (146 ) (147 ) (76 ) (68 ) (37 ) (42 ) Obligation at measurement date $ 7,727 $ 1,995 $ 2,451 $ 1,143 $ 1,276 $ 453 $ 649 Accumulated Benefit Obligation at measurement date $ 7,606 $ 1,993 $ 2,414 $ 1,143 $ 1,240 $ 442 $ 628 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 8,498 $ 2,300 $ 2,722 $ 1,321 $ 1,363 $ 456 $ 681 Obligation transferred with Midwest Generation Disposal Group (81 ) — — — — — — Employer contributions 302 91 83 42 40 8 19 Actual return on plan assets (50 ) (10 ) (22 ) (10 ) (11 ) (2 ) (3 ) Benefits paid (533 ) (146 ) (147 ) (76 ) (68 ) (37 ) (42 ) Transfers — 8 4 7 (3 ) 8 — Plan assets at measurement date $ 8,136 $ 2,243 $ 2,640 $ 1,284 $ 1,321 $ 433 $ 655 Funded status of plan $ 409 $ 248 $ 189 $ 141 $ 45 $ (20 ) $ 6
Amounts Recognized in the Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Prefunded pension (a) $ 518 $ 273 $ 225 $ 132 $ 91 $ 6 $ — Noncurrent pension liability (b) $ 118 $ — $ 62 $ — $ 62 $ 25 $ 1 Net asset recognized $ 400 $ 273 $ 163 $ 132 $ 29 $ (19 ) $ (1 ) Regulatory assets $ 2,098 $ 476 $ 805 $ 378 $ 426 $ 81 $ 171 Accumulated other comprehensive (income) loss Deferred income tax asset $ (41 ) $ — $ (6 ) $ — $ — $ — $ — Prior service credit (6 ) — — — — — — Net actuarial loss 123 — 16 — — — — Net amounts recognized in accumulated other comprehensive loss $ 76 $ — $ 10 $ — $ — $ — $ — Amounts to be recognized in net periodic pension costs in the next year Unrecognized net actuarial loss $ 147 $ 31 $ 52 $ 23 $ 29 $ 5 $ 8 Unrecognized prior service credit (24 ) (8 ) (3 ) (2 ) (1 ) — (2 ) December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Prefunded pension (a) $ 474 $ 252 $ 232 $ 145 $ 84 $ 1 $ 6 Noncurrent pension liability (b) $ 65 $ 4 $ 43 $ 4 $ 39 $ 21 $ — Net asset recognized $ 409 $ 248 $ 189 $ 141 $ 45 $ (20 ) $ 6 Regulatory assets $ 1,884 $ 472 $ 771 $ 360 $ 410 $ 79 $ 162 Accumulated other comprehensive (income) loss Deferred income tax asset $ (45 ) $ — $ (6 ) $ — $ — $ — $ — Prior service credit (4 ) — — — — — — Net actuarial loss 130 — 17 — — — — Net amounts recognized in accumulated other comprehensive loss (c) $ 81 $ — $ 11 $ — $ — $ — $ — (a) Included in Other within Investments and Other Assets on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets. (c) Excludes accumulated other comprehensive income of $13 million as of December 31, 2015 , net of tax, associated with a Brazilian retirement plan.
Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets	Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2016 Duke Duke Duke Progress Energy Energy (in millions) Energy Energy Florida Ohio Projected benefit obligation $ 1,299 $ 665 $ 665 $ 311 Accumulated benefit obligation 1,239 633 633 299 Fair value of plan assets 1,182 604 604 286 December 31, 2015 Duke Duke Duke Progress Energy Energy (in millions) Energy Energy Florida Ohio Projected benefit obligation $ 1,216 $ 611 $ 611 $ 307 Accumulated benefit obligation 1,158 575 575 298 Fair value of plan assets 1,151 574 574 289
Assumptions Used for Pension Benefits Accounting	The following tables present the assumptions or range of assumptions used for pension benefit accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10% 4.40% 4.10% Salary increase 4.00 % - 4.50% 4.00 % - 4.40% 4.00 % - 4.40% Net Periodic Benefit Cost Discount rate 4.40% 4.10% 4.70% Salary increase 4.00 % - 4.40% 4.00 % - 4.40% 4.00 % - 4.40% Expected long-term rate of return on plan assets 6.50 % - 6.75% 6.50% 6.75%
Expected Benefit Payments	Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ending December 31, 2017 $ 585 $ 162 $ 159 $ 84 $ 74 $ 35 $ 49 2018 595 171 159 83 75 33 49 2019 613 177 164 86 76 33 48 2020 632 186 171 90 79 34 47 2021 637 181 175 92 81 35 48 2022 – 2026 3,099 867 890 455 425 161 219
Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	Components of Net Periodic Pension Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 14 1 5 1 2 — — Amortization of actuarial loss 8 1 1 1 1 — — Amortization of prior service credit (1 ) — — — — — — Net periodic pension costs $ 23 $ 2 $ 6 $ 2 $ 3 $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ — $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 13 1 4 1 2 — — Amortization of actuarial loss 6 — 2 1 2 — 1 Amortization of prior service credit (1 ) — (1 ) — — — — Net periodic pension costs $ 21 $ 1 $ 6 $ 2 $ 4 $ — $ 1 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ — $ 1 $ 1 $ — $ — $ — Interest cost on projected benefit obligation 14 1 5 1 2 — — Amortization of actuarial loss 3 — 2 — — — — Amortization of prior service credit (1 ) — (1 ) — — — — Net periodic pension costs $ 19 $ 1 $ 7 $ 2 $ 2 $ — $ —
Amounts Recognized in AOCI and Regulatory Assets and Liabilities	Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net (decrease) increase $ (3 ) $ (2 ) $ 2 $ 1 $ 1 $ — $ (1 ) Regulatory liabilities, net increase (decrease) $ — $ — $ — $ — $ — $ — $ — Accumulated other comprehensive (income) loss Deferred income tax benefit $ — $ — $ — $ — $ — $ — $ — Prior service credit arising during the year (1 ) — — — — — — Actuarial loss arising during the year 1 — — — — — — Net amount recognized in accumulated other comprehensive loss (income) $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net (decrease) increase $ (13 ) $ 2 $ (16 ) $ (1 ) $ (15 ) $ — $ (1 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ (7 ) $ — $ (5 ) $ — $ — $ — $ — Amortization of prior service credit 1 — — — — — — Actuarial gains arising during the year 17 — 13 — — — — Net amount recognized in accumulated other comprehensive loss (income) $ 11 $ — $ 8 $ — $ — $ — $ —
Reconciliation of Funded Status to Net Amount Recognized	Reconciliation of Funded Status to Net Amount Recognized Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Obligation assumed from acquisition 5 — — — — — — Service cost 2 — — — — — — Interest cost 14 1 5 1 2 — — Actuarial losses (gains) 4 (1 ) 5 2 1 — (2 ) Plan amendments (2 ) — — — — — — Benefits paid (32 ) (2 ) (8 ) (3 ) (3 ) — — Obligation at measurement date $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Accumulated Benefit Obligation at measurement date $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Change in Fair Value of Plan Assets Benefits paid $ (32 ) $ (2 ) $ (8 ) $ (3 ) $ (3 ) $ — $ — Employer contributions 32 2 8 3 3 — — Plan assets at measurement date $ — $ — $ — $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Obligation at prior measurement date $ 337 $ 16 $ 116 $ 35 $ 61 $ 4 $ 5 Service cost 3 — 1 — — — — Interest cost 13 1 4 1 2 — — Actuarial losses (gains) 10 1 (1 ) — (14 ) — — Transfers 4 — — — — — — Benefits paid (26 ) (2 ) (8 ) (3 ) (3 ) — — Obligation at measurement date $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Accumulated Benefit Obligation at measurement date $ 336 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Change in Fair Value of Plan Assets Plan assets at prior measurement date — — — — — — — Benefits paid (26 ) (2 ) (8 ) (3 ) (3 ) — — Employer contributions 26 2 8 3 3 — — Plan assets at measurement date $ — $ — $ — $ — $ — $ — $ —
Amounts Recognized in the Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current pension liability (a) $ 28 $ 2 $ 8 $ 2 $ 3 $ — $ — Noncurrent pension liability (b) 304 12 106 31 43 4 3 Total accrued pension liability $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Regulatory assets $ 73 $ 5 $ 18 $ 7 $ 11 $ 1 $ — Accumulated other comprehensive (income) loss Deferred income tax asset $ (3 ) $ — $ (3 ) $ — $ — $ — $ — Prior service credit (1 ) — — — — — — Net actuarial loss 10 — 9 — — — — Net amounts recognized in accumulated other comprehensive income $ 6 $ — $ 6 $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss $ 7 $ — $ 2 $ 1 $ 1 $ — $ — Unrecognized prior service credit (2 ) — — — — — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current pension liability (a) $ 27 $ 2 $ 8 $ 3 $ 3 $ — $ — Noncurrent pension liability (b) 314 14 104 30 43 4 5 Total accrued pension liability $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Regulatory assets $ 76 $ 7 $ 16 $ 6 $ 10 $ 1 $ 1 Accumulated other comprehensive (income) loss Deferred income tax asset $ (3 ) $ — $ (3 ) $ — $ — $ — $ — Net actuarial loss 9 — 9 — — — — Net amounts recognized in accumulated other comprehensive loss $ 6 $ — $ 6 $ — $ — $ — $ — (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets.
Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets	Information for Plans with Accumulated Benefit Obligation in Excess of Plan Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Projected benefit obligation $ 332 $ 14 $ 114 $ 33 $ 46 $ 4 $ 3 Accumulated benefit obligation 332 14 114 33 46 4 3 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Projected benefit obligation $ 341 $ 16 $ 112 $ 33 $ 46 $ 4 $ 5 Accumulated benefit obligation 336 16 112 33 46 4 5
Assumptions Used for Pension Benefits Accounting	The following tables present the assumptions used for pension benefit accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10 % 4.40 % 4.10 % Salary increase 4.40 % 4.40 % 4.40 % Net Periodic Benefit Cost Discount rate 4.40 % 4.10 % 4.70 % Salary increase 4.40 % 4.40 % 4.40 %
Expected Benefit Payments	Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ending December 31, 2017 $ 29 $ 2 $ 8 $ 3 $ 3 $ — $ — 2018 25 2 8 3 3 — — 2019 25 2 8 2 3 — — 2020 24 2 8 2 3 — — 2021 24 1 8 2 3 — — 2021 - 2025 111 5 36 11 15 1 1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	Components of Net Periodic Other Post-Retirement Benefit Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 3 $ 1 $ 1 $ — $ 1 $ — $ — Interest cost on accumulated post-retirement benefit obligation 35 8 15 8 7 1 4 Expected return on plan assets (12 ) (8 ) — — — — (1 ) Amortization of actuarial loss (gain) 6 (3 ) 22 13 9 (2 ) (1 ) Amortization of prior service credit (141 ) (14 ) (103 ) (68 ) (35 ) — (1 ) Net periodic post-retirement benefit costs (a)(b) $ (109 ) $ (16 ) $ (65 ) $ (47 ) $ (18 ) $ (1 ) $ 1 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 6 $ 1 $ 1 $ 1 $ 1 $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 36 9 15 8 7 2 4 Expected return on plan assets (13 ) (8 ) — — — (1 ) (1 ) Amortization of actuarial loss (gain) 16 (2 ) 28 18 10 (2 ) (2 ) Amortization of prior service credit (140 ) (14 ) (102 ) (68 ) (35 ) — — Net periodic post-retirement benefit costs (a)(b) $ (95 ) $ (14 ) $ (58 ) $ (41 ) $ (17 ) $ (1 ) $ 2 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 10 $ 2 $ 4 $ 1 $ 3 $ — $ 1 Interest cost on accumulated post-retirement benefit obligation 49 12 22 11 12 2 5 Expected return on plan assets (13 ) (9 ) — — — — (1 ) Amortization of actuarial loss (gain) 39 3 42 31 10 (2 ) — Amortization of prior service credit (125 ) (11 ) (95 ) (73 ) (21 ) — — Net periodic post-retirement benefit costs (a)(b) $ (40 ) $ (3 ) $ (27 ) $ (30 ) $ 4 $ — $ 5 (a) Duke Energy amounts exclude $8 million , $10 million and $9 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006. (b) Duke Energy Ohio amounts exclude $2 million , $3 million and $2 million for the years ended December 2016, 2015 and 2014, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy's merger with Cinergy in April 2006.
Amounts Recognized in AOCI and Regulatory Assets and Liabilities	Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 53 $ — $ 47 $ 38 $ 9 $ — $ (6 ) Regulatory liabilities, net increase (decrease) $ (114 ) $ (22 ) $ (51 ) $ (25 ) $ (26 ) $ (2 ) $ (12 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ (2 ) $ — $ — $ — $ — $ — $ — Actuarial losses arising during the year 3 — — — — — — Amortization of prior year prior service credit 1 — 1 — — — — Net amount recognized in accumulated other comprehensive income $ 2 $ — $ 1 $ — $ — $ — $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Regulatory assets, net increase (decrease) $ 1 $ — $ 1 $ — $ 1 $ — $ (7 ) Regulatory liabilities, net increase (decrease) $ (92 ) $ (8 ) $ (71 ) $ (36 ) $ (35 ) $ 2 $ (8 ) Accumulated other comprehensive (income) loss Deferred income tax benefit $ 2 $ — $ (1 ) $ — $ — $ — $ — Actuarial losses (gains) arising during the year (5 ) — 2 — — — — Transfer with the Midwest Generation Disposal Group (3 ) — — — — — — Amortization of prior year prior service credit 3 — (1 ) — — — — Net amount recognized in accumulated other comprehensive income $ (3 ) $ — $ — $ — $ — $ — $ —
Reconciliation of Funded Status to Net Amount Recognized	Reconciliation of Funded Status to Accrued Other Post-Retirement Benefit Costs Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 828 $ 200 $ 354 $ 188 $ 164 $ 35 $ 87 Obligation assumed from acquisition 39 — — — — — — Service cost 3 1 1 — 1 — — Interest cost 35 8 15 8 7 1 4 Plan participants' contributions 19 3 7 4 3 1 2 Actuarial (gains) losses 33 5 16 8 8 — 3 Transfers — 1 — — — — — Plan amendments (1 ) — — — — (1 ) — Benefits paid (88 ) (17 ) (36 ) (17 ) (19 ) (4 ) (13 ) Accumulated post-retirement benefit obligation at measurement date $ 868 $ 201 $ 357 $ 191 $ 164 $ 32 $ 83 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 208 $ 134 $ — $ — $ 1 $ 8 $ 19 Assets received from acquisition 29 — — — — — — Actual return on plan assets 14 8 1 — — 1 2 Benefits paid (88 ) (17 ) (36 ) (17 ) (19 ) (4 ) (13 ) Employer contributions 62 9 29 13 15 1 12 Plan participants' contributions 19 3 7 4 3 1 2 Plan assets at measurement date $ 244 $ 137 $ 1 $ — $ — $ 7 $ 22 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Change in Projected Benefit Obligation Accumulated post-retirement benefit obligation at prior measurement date $ 916 $ 220 $ 379 $ 207 $ 170 $ 39 $ 96 Service cost 6 1 1 1 1 — 1 Interest cost 36 9 15 8 7 2 4 Plan participants' contributions 20 4 7 4 3 1 2 Actuarial (gains) losses (39 ) (18 ) (1 ) (13 ) 11 (3 ) 1 Transfers — 2 — — — — — Plan amendments (9 ) — — — — (1 ) (4 ) Benefits paid (100 ) (18 ) (47 ) (19 ) (28 ) (3 ) (13 ) Obligations transferred with the Midwest Generation Disposal Group (3 ) — — — — — — Accrued retiree drug subsidy 1 — — — — — — Accumulated post-retirement benefit obligation at measurement date $ 828 $ 200 $ 354 $ 188 $ 164 $ 35 $ 87 Change in Fair Value of Plan Assets Plan assets at prior measurement date $ 227 $ 145 $ — $ (1 ) $ — $ 8 $ 23 Actual return on plan assets (1 ) (1 ) 1 1 1 — (1 ) Benefits paid (100 ) (18 ) (47 ) (19 ) (28 ) (3 ) (13 ) Employer contributions 62 4 39 15 25 2 8 Plan participants' contributions 20 4 7 4 3 1 2 Plan assets at measurement date $ 208 $ 134 $ — $ — $ 1 $ 8 $ 19
Amounts Recognized in the Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current post-retirement liability (a) $ 38 $ — $ 31 $ 17 $ 15 $ 2 $ — Noncurrent post-retirement liability (b) 586 64 325 174 149 23 63 Total accrued post-retirement liability $ 624 $ 64 $ 356 $ 191 $ 164 $ 25 $ 63 Regulatory assets $ 54 $ — $ 48 $ 38 $ 10 $ — $ 51 Regulatory liabilities $ 174 $ 46 $ — $ — $ — $ 19 $ 71 Accumulated other comprehensive (income) loss Deferred income tax liability $ 5 $ — $ — $ — $ — $ — $ — Prior service credit (5 ) — — — — — — Net actuarial gain (10 ) — — — — — — Net amounts recognized in accumulated other comprehensive income $ (10 ) $ — $ — $ — $ — $ — $ — Amounts to be recognized in net periodic pension expense in the next year Unrecognized net actuarial loss (gain) $ 10 $ (2 ) $ 21 $ 12 $ 9 $ (2 ) $ (6 ) Unrecognized prior service credit (115 ) (10 ) (85 ) (55 ) (30 ) — (1 ) December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current post-retirement liability (a) $ 37 $ — $ 31 $ 16 $ 15 $ 2 $ — Noncurrent post-retirement liability (b) 583 66 323 172 149 25 68 Total accrued post-retirement liability $ 620 $ 66 $ 354 $ 188 $ 164 $ 27 $ 68 Regulatory assets $ 1 $ — $ 1 $ — $ 1 $ — $ 57 Regulatory liabilities $ 288 $ 68 $ 51 $ 25 $ 26 $ 21 $ 83 Accumulated other comprehensive (income) loss Deferred income tax liability $ 7 $ — $ — $ — $ — $ — $ — Prior service credit (6 ) — (1 ) — — — — Net actuarial gain (13 ) — — — — — — Net amounts recognized in accumulated other comprehensive income $ (12 ) $ — $ (1 ) $ — $ — $ — $ — (a) Included in Other within Current Liabilities on the Consolidated Balance Sheets. (b) Included in Accrued pension and other post-retirement benefit costs on the Consolidated Balance Sheets.
Assumptions Used for Pension Benefits Accounting	The following tables present the assumptions used for other post-retirement benefits accounting. December 31, 2016 2015 2014 Benefit Obligations Discount rate 4.10 % 4.40 % 4.10 % Net Periodic Benefit Cost Discount rate 4.40 % 4.10 % 4.70 % Expected long-term rate of return on plan assets 6.50 % 6.50 % 6.75 % Assumed tax rate 35 % 35 % 35 %
Assumed Health Care Cost Trend Rate	Assumed Health Care Cost Trend Rate December 31, 2016 2015 Health care cost trend rate assumed for next year 7.00 % 7.50 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that rate reaches ultimate trend 2023 2023
Sensitivity to Changes in Assumed Health Care Cost Trend Rates	Sensitivity to Changes in Assumed Health Care Cost Trend Rates Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana 1-Percentage Point Increase Effect on total service and interest costs $ 1 $ — $ 1 $ 1 $ — $ — $ — Effect on post-retirement benefit obligation 29 7 12 6 5 1 3 1-Percentage Point Decrease Effect on total service and interest costs (1 ) — (1 ) (1 ) — — — Effect on post-retirement benefit obligation (25 ) (6 ) (10 ) (6 ) (5 ) (1 ) (2 )
Expected Benefit Payments	Expected Benefit Payments Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Years ending December 31, 2017 $ 85 $ 18 $ 32 $ 17 $ 15 $ 4 $ 10 2018 81 18 31 16 15 3 9 2019 78 18 31 16 14 3 9 2020 75 18 30 16 14 3 8 2021 72 18 29 15 13 3 7 2021 – 2025 310 76 126 67 58 12 31

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Schedule of Components of Income Tax Expense (Benefit)	Components of Income Tax Expense Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 139 $ 15 $ (59 ) $ 76 $ (7 ) $ 7 State (15 ) 25 (19 ) (25 ) 22 (13 ) 6 Foreign 2 — — — — — — Total current income taxes (13 ) 164 (4 ) (84 ) 98 (20 ) 13 Deferred income taxes Federal 1,064 430 486 350 199 88 202 State 117 45 50 40 25 11 11 Total deferred income taxes (a) 1,181 475 536 390 224 99 213 Investment tax credit amortization (12 ) (5 ) (5 ) (5 ) — (1 ) (1 ) Income tax expense from continuing operations 1,156 634 527 301 322 78 225 Tax (benefit) expense from discontinued operations (30 ) — 1 — — (36 ) — Total income tax expense included in Consolidated Statements of Operations $ 1,126 $ 634 $ 528 $ 301 $ 322 $ 42 $ 225 (a) Includes benefits of net operating loss (NOL) carryforwards and tax credit carryforwards of $648 million at Duke Energy, $4 million at Duke Energy Carolinas, $190 million at Progress Energy, $60 million at Duke Energy Progress, $49 million at Duke Energy Florida, $26 million at Duke Energy Ohio and $58 million at Duke Energy Indiana. Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 216 $ (193 ) $ (56 ) $ 1 $ (18 ) $ (86 ) State (12 ) 14 1 (4 ) (7 ) (1 ) (12 ) Foreign 4 — — — — — — Total current income taxes (8 ) 230 (192 ) (60 ) (6 ) (19 ) (98 ) Deferred income taxes Federal 1,097 345 694 334 290 96 245 State 181 57 27 27 58 5 17 Total deferred income taxes (a) 1,278 402 721 361 348 101 262 Investment tax credit amortization (14 ) (5 ) (7 ) (7 ) — (1 ) (1 ) Income tax expense from continuing operations 1,256 627 522 294 342 81 163 Tax expense (benefit) from discontinued operations 89 — (1 ) — — 22 — Total income tax expense included in Consolidated Statements of Operations $ 1,345 $ 627 $ 521 $ 294 $ 342 $ 103 $ 163 (a) Includes benefits of NOL carryforwards and utilization of NOL and tax credit carryforwards of $264 million at Duke Energy, $15 million at Duke Energy Carolinas, $119 million at Progress Energy, $21 million at Duke Energy Progress, $84 million at Duke Energy Florida, $3 million at Duke Energy Ohio and $45 million at Duke Energy Indiana. Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current income taxes Federal $ — $ 161 $ (466 ) $ (184 ) $ (53 ) $ (73 ) $ (112 ) State 56 51 (8 ) 14 1 3 1 Foreign 6 — — — — — — Total current income taxes 62 212 (474 ) (170 ) (52 ) (70 ) (111 ) Deferred income taxes Federal 1,144 407 938 436 350 113 294 State 35 (25 ) 84 25 52 1 15 Total deferred income taxes (a)(b) 1,179 382 1,022 461 402 114 309 Investment tax credit amortization (16 ) (6 ) (8 ) (6 ) (1 ) (1 ) (1 ) Income tax expense from continuing operations 1,225 588 540 285 349 43 197 Tax expense (benefit) from discontinued operations 149 — (4 ) — — (300 ) — Total income tax expense (benefit) included in Consolidated Statements of Operations $ 1,374 $ 588 $ 536 $ 285 $ 349 $ (257 ) $ 197 (a) There were no benefits of NOL carryforwards. (b) Includes utilization of NOL carryforwards of $1,544 million at Duke Energy, $345 million at Duke Energy Carolinas, $530 million at Progress Energy, $291 million at Duke Energy Progress, $64 million at Duke Energy Florida, $56 million at Duke Energy Ohio and $141 million at Duke Energy Indiana.
Schedule of Income before Income Tax, Domestic and Foreign	Duke Energy Income from Continuing Operations before Income Taxes Years Ended December 31, (in millions) 2016 2015 2014 Domestic $ 3,689 $ 3,831 $ 3,637 Foreign 45 79 126 Income from continuing operations before income taxes $ 3,734 $ 3,910 $ 3,763
Summary of Effective Tax Rates	The following tables present a reconciliation of income tax expense at the U.S. federal statutory tax rate to the actual tax expense from continuing operations. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,307 $ 630 $ 548 $ 315 $ 306 $ 95 $ 212 State income tax, net of federal income tax effect 64 46 20 10 30 (2 ) 11 AFUDC equity income (70 ) (36 ) (26 ) (17 ) (9 ) (2 ) (6 ) Renewable energy production tax credits (97 ) — — — — — — Audit adjustment 5 3 — — — — — Tax true-up (14 ) (14 ) (11 ) (3 ) (9 ) (16 ) 2 Other items, net (39 ) 5 (4 ) (4 ) 4 3 6 Income tax expense from continuing operations $ 1,156 $ 634 $ 527 $ 301 $ 322 $ 78 $ 225 Effective tax rate 31.0 % 35.2 % 33.7 % 33.4 % 36.9 % 28.9 % 37.1 % Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,369 $ 598 $ 555 $ 302 $ 330 $ 81 $ 168 State income tax, net of federal income tax effect 109 46 18 15 33 2 2 AFUDC equity income (58 ) (34 ) (19 ) (17 ) (3 ) (1 ) (4 ) Renewable energy production tax credits (72 ) — (1 ) — — — — Audit adjustment (22 ) — (23 ) 1 (24 ) — — Tax true-up 2 2 (3 ) (4 ) 2 (5 ) (9 ) Other items, net (72 ) 15 (5 ) (3 ) 4 4 6 Income tax expense from continuing operations $ 1,256 $ 627 $ 522 $ 294 $ 342 $ 81 $ 163 Effective tax rate 32.1 % 36.7 % 32.9 % 34.2 % 36.3 % 35.2 % 34.0 % Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Income tax expense, computed at the statutory rate of 35 percent $ 1,317 $ 581 $ 497 $ 263 $ 314 $ 39 $ 195 State income tax, net of federal income tax effect 59 17 49 25 34 3 10 AFUDC equity income (47 ) (32 ) (9 ) (9 ) — (1 ) (5 ) Renewable energy production tax credits (67 ) — — — — — — Other items, net (37 ) 22 3 6 1 2 (3 ) Income tax expense from continuing operations $ 1,225 $ 588 $ 540 $ 285 $ 349 $ 43 $ 197 Effective tax rate 32.6 % 35.4 % 38.0 % 37.9 % 38.9 % 38.9 % 35.5 %
Schedule of Deferred Tax Assets and Liabilities	December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Deferred credits and other liabilities $ 201 $ 38 $ 115 $ 25 $ 66 $ 29 $ 5 Capital lease obligations 63 9 — — — — 2 Pension, post-retirement and other employee benefits 580 46 186 92 82 24 40 Progress Energy merger purchase accounting adjustments (a) 1,009 — — — — — — Tax credits and NOL carryforwards 3,631 170 997 163 177 25 215 Investments and other assets — — — — — 3 — Other 206 20 48 2 46 37 20 Valuation allowance (93 ) — (38 ) — — — — Total deferred income tax assets 5,597 283 1,308 282 371 118 282 Investments and other assets (1,573 ) (1,057 ) (412 ) (228 ) (201 ) — (7 ) Accelerated depreciation rates (12,939 ) (4,429 ) (4,169 ) (2,325 ) (1,868 ) (1,356 ) (1,797 ) Regulatory assets and deferred debits, net (3,633 ) (943 ) (1,517 ) (756 ) (762 ) (169 ) (135 ) Total deferred income tax liabilities (18,145 ) (6,429 ) (6,098 ) (3,309 ) (2,831 ) (1,525 ) (1,939 ) Net deferred income tax liabilities $ (12,548 ) $ (6,146 ) $ (4,790 ) $ (3,027 ) $ (2,460 ) $ (1,407 ) $ (1,657 ) (a) Primarily related to capital lease obligations and debt fair value adjustments. Net Deferred Income Tax Liability Components December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Deferred credits and other liabilities $ 382 $ 66 $ 126 $ 40 $ 93 $ 21 $ 4 Capital lease obligations 60 8 — — — — 1 Pension, post-retirement and other employee benefits 561 16 199 91 96 22 37 Progress Energy merger purchase accounting adjustments (a) 918 — — — — — — Tax credits and NOL carryforwards 4,682 192 1,165 222 232 49 278 Investments and other assets — — — — — 3 — Other 205 16 35 8 — 5 9 Valuation allowance (96 ) — (12 ) — — — — Total deferred income tax assets 6,712 298 1,513 361 421 100 329 Investments and other assets (1,892 ) (1,149 ) (597 ) (313 ) (297 ) — (21 ) Accelerated depreciation rates (14,872 ) (4,664 ) (4,490 ) (2,479 ) (2,038 ) (1,404 ) (1,938 ) Regulatory assets and deferred debits, net (4,103 ) (1,029 ) (1,672 ) (892 ) (780 ) (139 ) (270 ) Total deferred income tax liabilities (20,867 ) (6,842 ) (6,759 ) (3,684 ) (3,115 ) (1,543 ) (2,229 ) Net deferred income tax liabilities $ (14,155 ) $ (6,544 ) $ (5,246 ) $ (3,323 ) $ (2,694 ) $ (1,443 ) $ (1,900 ) (a) Primarily related to capital lease obligations and debt fair value adjustments.
Summary of Tax Credit Carryforwards	The following table presents the expiration of tax credits and NOL carryforwards. December 31, 2016 (in millions) Amount Expiration Year Investment tax credits $ 1,143 2027 — 2036 Alternative minimum tax credits 1,151 Indefinite Federal NOL carryforwards 1,267 2020 — 2036 State NOL carryforwards and credits (a) 248 2017 — 2036 Foreign NOL carryforwards (b) 12 2026 — 2036 Foreign Tax Credits 859 2024 — 2026 Charitable Carryforwards 2 2017 — 2019 Total tax credits and NOL carryforwards $ 4,682 (a) A valuation allowance of $84 million has been recorded on the state NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table. (b) A valuation allowance of $12 million has been recorded on the foreign NOL carryforwards, as presented in the Net Deferred Income Tax Liability Components table.
Schedule of Unrecognized Tax Benefits Roll Forward	The following tables present changes to unrecognized tax benefits. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Ohio Indiana Unrecognized tax benefits – January 1 $ 88 $ 72 $ 1 $ 3 $ — $ 1 Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods — — — — 4 — Gross decreases – tax positions in prior periods (4 ) (4 ) (1 ) (1 ) — — Decreases due to settlements (68 ) (67 ) — — — (1 ) Reduction due to lapse of statute of limitations 1 — 2 — — — Total changes (71 ) (71 ) 1 (1 ) 4 (1 ) Unrecognized tax benefits – December 31 $ 17 $ 1 $ 2 $ 2 $ 4 $ — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Unrecognized tax benefits – January 1 $ 213 $ 160 $ 32 $ 23 $ 8 $ 1 Unrecognized tax benefits increases (decreases) Gross increases – tax positions in prior periods — — 1 1 — — Gross decreases – tax positions in prior periods (48 ) (45 ) — — — — Decreases due to settlements (45 ) (43 ) — — — — Reduction due to lapse of statute of limitations (32 ) — (32 ) (21 ) (8 ) — Total changes (125 ) (88 ) (31 ) (20 ) (8 ) — Unrecognized tax benefits – December 31 $ 88 $ 72 $ 1 $ 3 $ — $ 1 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Unrecognized tax benefits – January 1 $ 230 $ 171 $ 32 $ 22 $ 8 $ 1 Unrecognized tax benefits increases (decreases) Gross increases — tax positions in prior periods — — 1 1 — — Gross decreases – tax positions in prior periods (2 ) — — — — — Decreases due to settlements (15 ) (11 ) (1 ) — — — Total changes (17 ) (11 ) — 1 — — Unrecognized tax benefits – December 31 $ 213 $ 160 $ 32 $ 23 $ 8 $ 1
Schedule of Unrecognized Tax Benefits	The following table includes additional information regarding the Duke Energy Registrants' unrecognized tax benefits. It is reasonably possible that Duke Energy could reflect an approximate $8 million reduction and Duke Energy Carolinas could reflect an approximate $1 million reduction in unrecognized tax benefits within the next 12 months. All other Duke Energy Registrants do not anticipate a material increase or decrease in unrecognized tax benefits within the next 12 months. December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Amount that if recognized, would affect the effective tax rate or regulatory liability (a) $ 8 $ 1 $ 2 $ 2 $ — $ — $ — Amount that if recognized, would be recorded as a component of discontinued operations 5 — — — — 2 — (a) Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana are unable to estimate the specific amounts that would affect the effective tax rate versus the regulatory liability.
Summary of Income Tax Contingencies	The following tables include interest recognized in the Consolidated Statements of Operations and the Consolidated Balance Sheets. Year Ended December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Net interest income recognized related to income taxes $ — $ — $ 1 $ — $ 2 Net interest expense recognized related to income taxes — 7 — — — Interest payable related to income taxes 4 23 1 1 — Year Ended December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Indiana Net interest income recognized related to income taxes $ 12 $ — $ 2 $ 2 $ 1 $ 1 Net interest expense recognized related to income taxes — 1 — — — — Interest receivable related to income taxes 3 — — — — 3 Interest payable related to income taxes — 14 — 1 — — Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Net interest income recognized related to income taxes $ 6 $ — $ 3 $ — $ 1 $ 4 $ 4 Net interest expense recognized related to income taxes — 1 — 1 — — — Interest receivable related to income taxes — — — — — — 2 Interest payable related to income taxes 13 13 5 3 5 — —

Other Income and Expenses, Net

Other Income and Expenses, Net (Tables)	12 Months Ended
	Dec. 31, 2016
Component Of Other Income Expense Nonoperating [Line Items]
Schedule of Other Income and Expenses, Net	The components of Other income and expenses, net on the Consolidated Statements of Operations are as follows. Year Ended December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 21 $ 4 $ 4 $ 3 $ 2 $ 5 $ 6 AFUDC equity 200 102 76 50 26 6 16 Post in-service equity returns 67 55 12 12 — — — Nonoperating income (expense), other 36 1 22 6 16 (2 ) — Other income and expense, net $ 324 $ 162 $ 114 $ 71 $ 44 $ 9 $ 22 Year Ended December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 20 $ 2 $ 4 $ 2 $ 2 $ 4 $ 6 AFUDC equity 164 96 54 47 7 3 11 Post in-service equity returns 73 60 13 13 — — — Nonoperating income (expense), other 33 2 26 9 15 (1 ) (6 ) Other income and expense, net $ 290 $ 160 $ 97 $ 71 $ 24 $ 6 $ 11 Year Ended December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Interest income $ 16 $ 4 $ 3 $ — $ 2 $ 8 $ 6 AFUDC equity 135 91 26 25 — 4 14 Post in-service equity returns 89 71 17 17 — — — Nonoperating income (expense), other 80 6 31 9 18 (2 ) 2 Other income and expense, net $ 320 $ 172 $ 77 $ 51 $ 20 $ 10 $ 22

Quarterly Financial Data (Una59

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	Quarterly EPS amounts may not sum to the full-year total due to changes in the weighted average number of common shares outstanding and rounding. First Second Third Fourth (in millions, except per share data) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 5,377 $ 5,213 $ 6,576 $ 5,577 $ 22,743 Operating income 1,240 1,259 1,954 888 5,341 Income from continuing operations 577 624 1,001 376 2,578 Income (loss) from discontinued operations, net of tax 122 (112 ) 180 (598 ) (408 ) Net income (loss) 699 512 1,181 (222 ) 2,170 Net income (loss) attributable to Duke Energy Corporation 694 509 1,176 (227 ) 2,152 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic $ 0.83 $ 0.90 $ 1.44 $ 0.53 $ 3.71 Diluted $ 0.83 $ 0.90 $ 1.44 $ 0.53 $ 3.71 Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders Basic $ 0.18 $ (0.16 ) $ 0.26 $ (0.86 ) $ (0.60 ) Diluted $ 0.18 $ (0.16 ) $ 0.26 $ (0.86 ) $ (0.60 ) Net income (loss) attributable to Duke Energy Corporation common stockholders Basic $ 1.01 $ 0.74 $ 1.70 $ (0.33 ) $ 3.11 Diluted $ 1.01 $ 0.74 $ 1.70 $ (0.33 ) $ 3.11 2015 Operating revenues $ 5,792 $ 5,302 $ 6,202 $ 5,075 $ 22,371 Operating income 1,390 1,192 1,606 890 5,078 Income from continuing operations 755 576 890 433 2,654 Income (Loss) from discontinued operations, net of tax 112 (29 ) 45 49 177 Net income 867 547 935 482 2,831 Net income attributable to Duke Energy Corporation 864 543 932 477 2,816 Earnings per share: Income from continuing operations attributable to Duke Energy Corporation common stockholders Basic $ 1.06 $ 0.83 $ 1.29 $ 0.62 $ 3.80 Diluted $ 1.06 $ 0.83 $ 1.29 $ 0.62 $ 3.80 Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders Basic $ 0.16 $ (0.05 ) $ 0.06 $ 0.07 $ 0.25 Diluted $ 0.16 $ (0.05 ) $ 0.06 $ 0.07 $ 0.25 Net income attributable to Duke Energy Corporation common stockholders Basic $ 1.22 $ 0.78 $ 1.35 $ 0.69 $ 4.05 Diluted $ 1.22 $ 0.78 $ 1.35 $ 0.69 $ 4.05
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers (see Note 2) $ (120 ) $ (111 ) $ (84 ) $ (208 ) $ (523 ) Commercial Renewables Impairment (see Note 12) — — (71 ) — (71 ) Loss on Sale of International Disposal Group (see Note 2) — — — (514 ) (514 ) Impairment of Assets in Central America (see Note 2) — (194 ) — — (194 ) Cost Savings Initiatives (see Note 19) (20 ) (24 ) (19 ) (29 ) (92 ) Total $ (140 ) $ (329 ) $ (174 ) $ (751 ) $ (1,394 ) 2015 Costs to Achieve Mergers $ (21 ) $ (22 ) $ (24 ) $ (30 ) $ (97 ) Edwardsport Settlement (see Note 4) — — (90 ) (3 ) (93 ) Ash Basin Settlement and Penalties (see Note 5) — — (7 ) (7 ) (14 ) State Tax Adjustment related to Midwest Generation Sale — (41 ) — — (41 ) Cost Savings Initiatives (see Note 19) — — — (142 ) (142 ) Total $ (21 ) $ (63 ) $ (121 ) $ (182 ) $ (387 )
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY CAROLINAS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,740 $ 1,675 $ 2,226 $ 1,681 $ 7,322 Operating income 481 464 815 302 2,062 Net income 271 261 494 140 1,166 2015 Operating revenues $ 1,901 $ 1,707 $ 2,061 $ 1,560 $ 7,229 Operating income 515 483 666 296 1,960 Net income 292 265 383 141 1,081
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (11 ) $ (12 ) $ (13 ) $ (68 ) $ (104 ) Cost Savings Initiatives (see Note 19) (10 ) (10 ) (8 ) (11 ) (39 ) Total $ (21 ) $ (22 ) $ (21 ) $ (79 ) $ (143 ) 2015 Costs to Achieve Mergers $ (9 ) $ (11 ) $ (11 ) $ (16 ) $ (47 ) Ash Basin Settlement and Penalties (see Note 5) — — (1 ) (7 ) (8 ) Cost Savings Initiatives (see Note 19) — — — (93 ) (93 ) Total $ (9 ) $ (11 ) $ (12 ) $ (116 ) $ (148 )
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	PROGRESS ENERGY First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 2,332 $ 2,348 $ 2,965 $ 2,208 $ 9,853 Operating income 475 560 814 292 2,141 Income from continuing operations 212 274 449 104 1,039 Net income 212 274 449 106 1,041 Net income attributable to Parent 209 272 446 104 1,031 2015 Operating revenues $ 2,536 $ 2,476 $ 2,929 $ 2,336 $ 10,277 Operating income 549 504 756 351 2,160 Income from continuing operations 264 217 452 132 1,065 Net income 263 217 451 131 1,062 Net income attributable to Parent 260 215 448 128 1,051
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (7 ) $ (8 ) $ (10 ) $ (44 ) $ (69 ) Cost Savings Initiatives (see Note 19) (8 ) (8 ) (10 ) (14 ) (40 ) Total $ (15 ) $ (16 ) $ (20 ) $ (58 ) $ (109 ) 2015 Costs to Achieve Mergers $ (8 ) $ (8 ) $ (8 ) $ (10 ) $ (34 ) Ash Basin Settlement and Penalties (see Note 5) — — (6 ) — (6 ) Cost Savings Initiatives (see Note 19) — — — (36 ) (36 ) Total $ (8 ) $ (8 ) $ (14 ) $ (46 ) $ (76 )
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY PROGRESS First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,307 $ 1,213 $ 1,583 $ 1,174 $ 5,277 Operating income 258 255 438 135 1,086 Net income 137 131 271 60 599 2015 Operating revenues $ 1,449 $ 1,193 $ 1,488 $ 1,160 $ 5,290 Operating income 316 184 394 130 1,024 Net income 183 85 229 69 566
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (5 ) $ (5 ) $ (6 ) $ (40 ) $ (56 ) Cost Savings Initiatives (see Note 19) (5 ) (5 ) (7 ) (6 ) (23 ) Total $ (10 ) $ (10 ) $ (13 ) $ (46 ) $ (79 ) 2015 Costs to Achieve Mergers $ (5 ) $ (5 ) $ (6 ) $ (6 ) $ (22 ) Ash Basin Settlement and Penalties (see Note 5) — — (6 ) — (6 ) Cost Savings Initiatives (see Note 19) — — — (28 ) (28 ) Total $ (5 ) $ (5 ) $ (12 ) $ (34 ) $ (56 )
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY FLORIDA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 1,024 $ 1,133 $ 1,381 $ 1,030 $ 4,568 Operating income 213 300 373 155 1,041 Net income 110 171 206 64 551 2015 Operating revenues $ 1,086 $ 1,281 $ 1,436 $ 1,174 $ 4,977 Operating income 227 315 357 216 1,115 Net income 113 165 216 105 599
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (2 ) $ (3 ) $ (4 ) $ (4 ) $ (13 ) Cost Savings Initiatives (see Note 19) (2 ) (3 ) (3 ) (9 ) (17 ) Total $ (4 ) $ (6 ) $ (7 ) $ (13 ) $ (30 ) 2015 Costs to Achieve Mergers $ (3 ) $ (3 ) $ (3 ) $ (4 ) $ (13 ) Cost Savings Initiatives (see Note 19) — — — (8 ) (8 ) Total $ (3 ) $ (3 ) $ (3 ) $ (12 ) $ (21 )
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY OHIO First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 516 $ 428 $ 489 $ 511 $ 1,944 Operating income 96 55 106 90 347 Income from discontinued operations, net of tax 2 — 34 — 36 Net income 59 23 89 57 228 2015 Operating revenues $ 586 $ 405 $ 462 $ 452 $ 1,905 Operating income 111 43 76 73 303 Income (Loss) from discontinued operations, net of tax 90 (65 ) (2 ) — 23 Net income (loss) 149 (52 ) 32 43 172
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (1 ) $ (1 ) $ (2 ) $ (2 ) $ (6 ) Cost Savings Initiatives (see Note 19) (1 ) (1 ) — (1 ) (3 ) Total $ (2 ) $ (2 ) $ (2 ) $ (3 ) $ (9 ) 2015 Costs to Achieve Mergers $ (1 ) $ (1 ) $ (1 ) $ (1 ) $ (4 ) Cost Savings Initiatives (see Note 19) — — — (2 ) (2 ) Total $ (1 ) $ (1 ) $ (1 ) $ (3 ) $ (6 )
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Schedule Of Quarterly Financial Information	DUKE ENERGY INDIANA First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Operating revenues $ 714 $ 702 $ 809 $ 733 $ 2,958 Operating income 176 174 239 176 765 Net income 95 85 129 72 381 2015 Operating revenues $ 788 $ 686 $ 749 $ 667 $ 2,890 Operating income 210 146 117 171 644 Net income 108 68 46 94 316
Schedule Of Unusual Or Infrequently Occurring Items	The following table includes unusual or infrequently occurring items in each quarter during the two most recently completed fiscal years. All amounts discussed below are pretax. First Second Third Fourth (in millions) Quarter Quarter Quarter Quarter Total 2016 Costs to Achieve Mergers $ (1 ) $ (2 ) $ (3 ) $ (3 ) $ (9 ) Cost Savings Initiatives (see Note 19) (1 ) (4 ) (1 ) (1 ) (7 ) Total $ (2 ) $ (6 ) $ (4 ) $ (4 ) $ (16 ) 2015 Costs to Achieve Mergers $ (2 ) $ (1 ) $ (2 ) $ (2 ) $ (7 ) Edwardsport Settlement (see Note 4) — — (90 ) (3 ) (93 ) Cost Savings Initiatives (see Note 19) — — — (6 ) (6 ) Total $ (2 ) $ (1 ) $ (92 ) $ (11 ) $ (106 )

Summary of Significant Accoun60

Summary of Significant Accounting Policies (Narrative)(Details) - USD ($) $ in Millions	Oct. 03, 2016	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash [Abstract]
Restricted cash			$ 137	$ 98
Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Annual Reduction In Excise Taxes			160
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Payments to Acquire Businesses, Gross			10	1,249
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Payments to Acquire Businesses, Gross				$ 1,249
Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Annual Reduction In Excise Taxes			$ 110
Utility Franchise Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate		3.22%
Utility Franchise Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate		3.22%
Electricity Sales Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate		3.00%
Electricity Sales Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate		3.00%
Current [Member] | Electricity Sales Tax Member [Member] | Duke Energy Carolinas [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate			7.00%
Current [Member] | Electricity Sales Tax Member [Member] | Duke Energy Progress [Member] | State [Member]
Organization And Basis Of Presentation [Line Items]
Statutory Tax Rate			7.00%
Piedmont Natural Gas [Member]
Organization And Basis Of Presentation [Line Items]
Payments to Acquire Businesses, Gross	$ 5,000

Summary of Significant Accoun61

Summary of Significant Accounting Policies (Other Assets and Liabilities)(Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Other current receivables	$ 751	$ 515
Collateral assets		30
Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	765	619
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	160	142
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	248	213
Collateral liabilities	155	141
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	114	151
Collateral assets		30
Progress Energy [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	19	129
Progress Energy [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	363	373
Derivative liabilities	1	201
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	51	87
Duke Energy Progress [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	16	111
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	141	141
Accrued compensation	135	108
Derivative liabilities		76
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	61	60
Collateral assets		30
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	222	232
Derivative liabilities	1	125
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	71	66
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	16	59
Other current receivables		33
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued litigation reserve	4	80
Collateral liabilities	62	48
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	105	96
Duke Energy Indiana [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Collateral liabilities	$ 44	$ 44

Summary of Significant Accoun62

Summary of Significant Accounting Policies (Amounts Attributable to Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income (Loss) Attributable to Parent [Abstract]
Income (Loss) from Continuing Operations	$ 376	$ 1,001	$ 624	$ 577	$ 433	$ 890	$ 576	$ 755	$ 2,578	$ 2,654	$ 2,538
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interests									7	9	5
Income (Loss) from Continuing Operations Attributable to Parent									2,571	2,645	2,533
Income (Loss) From Discontinued Operations, net of tax	(598)	180	(112)	122	49	45	(29)	112	(408)	177	(649)
Income (Loss) from Discontinued Operations Attributable to Noncontrolling Interest, net of tax									11	6	1
(Loss) Income from Discontinued Operations Attributable to Parent, net of tax									(419)	171	(650)
Net Income (Loss)	(222)	1,181	512	699	482	935	547	867	2,170	2,831	1,889
Net Income Attributable to Noncontrolling Interest									18	15	6
Net Income (Loss) Attributable to Parent	$ (227)	$ 1,176	$ 509	$ 694	$ 477	$ 932	$ 543	$ 864	$ 2,152	$ 2,816	$ 1,883

Summary of Significant Accoun63

Summary of Significant Accounting Policies (Inventory)(Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Public Utilities, Inventory [Line Items]
Materials and supplies	$ 2,374	$ 2,343
Coal	774	1,105
Natural gas, oil, other	374	298
Total inventory	3,522	3,746
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	767	785
Coal	251	451
Natural gas, oil, other	37	40
Total inventory	1,055	1,276
Progress Energy [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	1,167	1,133
Coal	314	370
Natural gas, oil, other	236	248
Total inventory	1,717	1,751
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	813	776
Coal	148	192
Natural gas, oil, other	115	120
Total inventory	1,076	1,088
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	354	357
Coal	166	178
Natural gas, oil, other	121	128
Total inventory	641	663
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	84	81
Coal	19	16
Natural gas, oil, other	34	8
Total inventory	137	105
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Materials and supplies	312	301
Coal	190	267
Natural gas, oil, other	2	2
Total inventory	$ 504	$ 570

Summary of Significant Accoun64

Summary of Significant Accounting Policies (Property, Plant and Equipment)(Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.80%	2.90%	2.80%
Duke Energy Carolinas [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.80%	2.80%	2.70%
Progress Energy [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.70%	2.60%	2.50%
Duke Energy Progress [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.60%	2.60%	2.50%
Duke Energy Florida [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.80%	2.70%	2.70%
Duke Energy Ohio [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	2.60%	2.70%	2.30%
Duke Energy Indiana [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Weighted-average depreciation rate	3.10%	3.00%	3.00%

Summary of Significant Accoun65

Summary of Significant Accounting Policies (Unbilled Revenues)(Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 831	$ 677
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	313	283
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	161	172
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	102	102
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	59	70
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	2	3
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	32	31
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	97	71
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 123	$ 97

Summary of Significant Accoun66

Summary of Significant Accounting Policies (Allowance for Doubtful Accounts)(Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	$ 14	$ 12	$ 14
Receivables of VIEs, allowance for doubtful accounts	54	53	51
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	3	3
Receivables of VIEs, allowance for doubtful accounts	7	7	6
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	6	6	8
Receivables of VIEs, allowance for doubtful accounts	7	8	8
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	4	4	7
Receivables of VIEs, allowance for doubtful accounts	5	5	5
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	2	2
Receivables of VIEs, allowance for doubtful accounts	2	3	3
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	2	2
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	$ 1	$ 1	$ 1

Summary of Significant Accoun67

Summary of Significant Accounting Policies (Excise Taxes)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Excise taxes	$ 362	$ 396	$ 498
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	31	31	94
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	213	229	263
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	18	16	56
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	195	213	207
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	100	102	103
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes	$ 17	$ 34	$ 38

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisitions (Narrative) (Details) shares in Millions, $ in Millions	Oct. 03, 2016USD ($)	Dec. 31, 2016USD ($)shares	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2015USD ($)MW	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Oct. 31, 2016shares	Aug. 31, 2016USD ($)	Aug. 01, 2016USD ($)
Business Acquisition [Line Items]
Net Income (Loss) Attributable to Parent		$ (227)	$ 1,176	$ 509	$ 694	$ 477	$ 932	$ 543	$ 864		$ 2,152	$ 2,816	$ 1,883
Long-term Debt		$ 47,895				38,868					47,895	38,868
Asset retirement obligations assumed											22	226
Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 5,000
Long-term debt assumed	$ 2,002
Business Combination, Integration Related Costs											439	9
Business Combination, After Tax Integration Related Costs											279	19
Revenues											367
Net Income (Loss) Attributable to Parent											$ 20
Long-term Debt															$ 3,750
Bridge Facility																$ 4,900
Forward Contract Indexed to Issuer's Equity, Indexed Shares | shares		10.6									10.6			10.6
Proceeds from Issuance or Sale of Equity											$ 723
Duke Energy Progress [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross												1,249
Net Income (Loss) Attributable to Parent		$ 60	271	$ 131	$ 137	69	229	$ 85	$ 183		599	566	$ 467
Long-term Debt		7,011				$ 6,518					7,011	6,518
Asset retirement obligations assumed												$ 204
Duke Energy Progress [Member] | NCEMPA Generating Assets [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross										$ 1,250
Owned Plant Capacity | MW										700
Acquisition adjustment, recorded within property, plant and equipment							350			$ 350
Nuclear decommissioning trust fund assets transferred							$ 287			287
Asset retirement obligations assumed										$ 204
Interest Rate Contract [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments											190
Sales [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											10
Operating Expense [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											101
Operating Income (Loss) [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											46
Interest Expense [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											234
August 2016 Term Loan Facility [Member]
Business Acquisition [Line Items]
Long-term Line of Credit		750									750
Bridge Facility																$ 1,500
August 2016 Term Loan Facility [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Long-term Line of Credit		$ 750	750								750
Bridge Facility			$ 1,500
Other Expense [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											104
Other Expense [Member] | Operating Expense [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											94
Other Expense [Member] | Operating Income (Loss) [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs											$ 10

Acquisitions and Dispositions69

Acquisitions and Dispositions - Dispositions (Narrative) (Details) $ in Millions	Apr. 02, 2015USD ($)MW	Dec. 31, 2016USD ($)MW
International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses		$ 1,900
DEI Latin American [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Plant Capacity | MW		2,230
Enterprise Value		$ 1,200
DEI Brazil Holdings [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Plant Capacity | MW		2,090
Enterprise Value		$ 1,200
Duke Energy Ohio [Member] | Midwest Generation Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Plant Capacity | MW	5,900
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 2,800
Obligations [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tax obligations		$ 78

Acquisitions and Dispositions70

Acquisitions and Dispositions (Purchase Price Allocation) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Oct. 03, 2016	Dec. 31, 2015
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill	$ 19,425		$ 16,072
Piedmont Natural Gas [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Current assets		$ 497
Net property, plant and equipment		4,714
Goodwill		3,353
Other long-term assets		804
Total assets		9,368
Current liabilities, including current maturities of long-term debt		576
Long-term liabilities		1,790
Long-term debt		2,002
Total liabilities		4,368
Total purchase price		$ 5,000

Acquisitions and Dispositions71

Acquisitions and Dispositions (Pro Forma Information) (Details) - Piedmont Natural Gas [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Revenues	$ 23,504	$ 23,570
Net income attributable to Duke Energy Corporation	$ 2,442	$ 2,877

Acquisitions and Dispositions72

Acquisitions and Dispositions (NCEMPA Assets Acquired) (Details) - Duke Energy Progress [Member] - NCEMPA Generating Assets [Member] $ in Millions	Sep. 30, 2015USD ($)
Business Acquisition [Line Items]
Inventory	$ 56
Property, plant and equipment, net	845
Total assets	901
Acquisition adjustment, recorded within property, plant and equipment	350
Total purchase price	$ 1,251

Acquisitions and Dispositions73

Acquisitions and Dispositions (Duke Energy Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) From Discontinued Operations, net of tax	$ (598)	$ 180	$ (112)	$ 122	$ 49	$ 45	$ (29)	$ 112	$ (408)	$ 177	$ (649)
Midwest Generation Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) From Discontinued Operations, net of tax									36	33	(524)
Other Disposal Groups [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) From Discontinued Operations, net of tax									90	(13)	(52)
Discontinued Operations, Disposed of by Sale [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) From Discontinued Operations, net of tax									$ (534)	$ 157	$ (73)

Acquisitions and Dispositions74

Acquisitions and Dispositions (Assets Held For Sale) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Significant Acquisitions and Disposals [Line Items]
Total assets held for sale		$ 746
Total liabilities associated with assets held for sale		279
International Energy [Member] | Discontinued Operations, Held-for-sale [Member]
Significant Acquisitions and Disposals [Line Items]
Cash and cash equivalents		474
Receivables, net		188
Inventory		65
Other		19
Total current assets held for sale		746
Cost		2,859
Accumulated depreciation and amortization		(930)
Net Property, Plant and Equipment		1,929
Goodwill		271
Other		213
Total noncurrent assets held for sale		2,413
Total assets held for sale		3,159
Accounts Payable		51
Taxes accrued		60
Current maturities of long-term debt		48
Other		120
Total current liabilities associated with assets held for sale		279
Long-term Debt		653
Deferred income taxes		157
Other		90
Total noncurrent liabilities associated with assets held for sale		900
Total liabilities associated with assets held for sale		$ 1,179
Goodwill, Period Increase (Decrease)	$ 7
Disposal Group, Including Discontinued Operation, Goodwill	$ 278

Acquisitions and Dispositions75

Acquisitions and Dispositions (International Energy Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit)									$ (30)	$ 89	$ 149
Income (Loss) From Discontinued Operations, net of tax	$ (598)	$ 180	$ (112)	$ 122	$ 49	$ 45	$ (29)	$ 112	(408)	177	(649)
Asset Impairment Charges									18	106	81
International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Impairment Charges									194
Cumulative foreign currency translation losses									620
Income (Loss) from Discontinued Operation, before Income Tax, Attributable to Parent									(445)	221	360
Income tax expense on disposal									126
After-tax loss on disposal									640
Previously Remitted Earnings [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Foreign Income Tax Expense (Benefit), Continuing Operations									(95)
Previously Remitted Earnings [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Foreign Income Tax Expense (Benefit), Continuing Operations									(95)		373
Discontinued Operations, Disposed of by Sale [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues									988	1,088	1,417
Fuel used in electric generation and purchased power									227	306	486
Cost of natural gas									43	53	63
Operation, maintenance and other									341	334	352
Depreciation and amortization									62	92	97
Property and other taxes									15	7	9
Impairment charges									194	13
(Loss) Gains on Sales of Other Assets and Other, net									(3)	6	6
Other income and expenses, net									58	23	47
Interest Expense									82	85	93
Pretax loss on disposal									(514)
(Loss) Income before income taxes									(435)	227	370
Income tax expense (benefit)									99	70	443
Income (Loss) From Discontinued Operations, net of tax									$ (534)	$ 157	$ (73)

Acquisitions and Dispositions76

Acquisitions and Dispositions (Cash Flow Statement) (Details) - International Energy [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities	$ 204	$ 248	$ 339
Investing Activities	$ (434)	$ 177	$ 111

Acquisitions and Dispositions77

Acquisitions and Dispositions (Midwest Generation Exit) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit)									$ (30)	$ 89	$ 149
Income (Loss) From Discontinued Operations, net of tax	$ (598)	$ 180	$ (112)	$ 122	$ 49	$ 45	$ (29)	$ 112	(408)	177	(649)
Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit)									(36)	22	(300)
Income (Loss) From Discontinued Operations, net of tax		$ 34		$ 2		$ (2)	$ (65)	$ 90	36	23	(563)
Midwest Generation Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues										543	1,748
Loss on disposition										(45)	(929)
Income (loss) before income taxes										59	(818)
Income tax expense (benefit)									(36)	26	(294)
Income (Loss) From Discontinued Operations, net of tax									36	33	(524)
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues										412	1,299
Loss on disposition										(52)	(959)
Income (loss) before income taxes										44	(863)
Income tax expense (benefit)									(36)	21	(300)
Income (Loss) From Discontinued Operations, net of tax									$ 36	23	$ (563)
Antitrust Lawsuit [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation Settlement, Expense										81
Antitrust Lawsuit [Member] | Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation Settlement, Expense										$ 81

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Interest expense	$ 1,916	$ 1,527	$ 1,529
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Interest expense	$ 424	412	407
Progress Energy [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Interest expense	$ 689	670	675
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Interest expense	$ 257	235	234
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Interest expense	$ 212	198	201
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Interest expense	$ 86	79	86
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Interest expense	$ 181	176	171
Other Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Interest expense	693	393	409
Other Segment [Member] | Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest expense	221	240	241
Other Segment [Member] | Duke Energy Ohio [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Interest expense	$ 1	$ 1	$ 5
National Methanol Company [Member] | Other [Member]
Segment Reporting Information [Line Items]
Equity method investment, ownership percentage	25.00%
National Methanol Company [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Equity method investment, ownership percentage	25.00%

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	Oct. 03, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		$ 5,577	$ 6,576	$ 5,213	$ 5,377	$ 5,075	$ 6,202	$ 5,302	$ 5,792	$ 22,743	$ 22,371	$ 22,509
Interest expense										1,916	1,527	1,529
Depreciation and amortization										3,294	3,053	2,969
Equity in earnings (losses) of unconsolidated affiliates										(15)	69	130
Income tax expense (benefit) from continuing operations										1,156	1,256	1,225
Segment income										2,571	2,645	2,533
Add back noncontrolling interests component										7	9	5
Income (Loss) From Discontinued Operations, net of tax		(598)	180	(112)	122	49	45	(29)	112	(408)	177	(649)
Net income (loss)		(222)	1,181	512	699	482	935	547	867	2,170	2,831	1,889
Net Income (Loss) Attributable to Parent		(227)	1,176	509	694	477	932	543	864	2,152	2,816	1,883
Impairment charges										18	106	81
Costs to achieve mergers		208	84	111	120	30	24	22	21	523	97
Current State and Local Tax Expense (Benefit)										(15)	(12)	56
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										13,215	8,363	5,528
Assets		132,761				121,156				132,761	121,156	120,557
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		511	489	428	516	452	462	405	586	1,944	1,905	1,913
Interest expense										86	79	86
Depreciation and amortization										233	227	214
Income tax expense (benefit) from continuing operations										78	81	43
Segment income										192	149	68
Income (Loss) From Discontinued Operations, net of tax			34		2		(2)	(65)	90	36	23	(563)
Net Income (Loss) Attributable to Parent		57	89	23	59	43	32	(52)	149	228	172	(495)
Impairment charges												94
Costs to achieve mergers		2	$ 2	$ 1	$ 1	1	$ 1	$ 1	$ 1	6	4
Current State and Local Tax Expense (Benefit)										(13)	(1)	3
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										476	399	322
Assets		7,528				7,097				7,528	7,097	9,993
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(125)	(112)	(112)
Interest expense										(12)	(9)	(24)
Segment income										1		18
Segment Reporting Information Assets [Abstract]
Assets		188				188				188	188	190
Intersegment Eliminations [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues												(1)
Interest expense												1
Segment income											(1)	(1)
Segment Reporting Information Assets [Abstract]
Assets		(12)				(9)				(12)	(9)	(243)
Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										21,336	21,489	21,655
Equity in earnings (losses) of unconsolidated affiliates										5	(2)	(1)
Electric Utilities and Infrastructure [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										21,366	21,521	21,691
Interest expense										1,136	1,074	1,057
Depreciation and amortization										2,897	2,735	2,686
Equity in earnings (losses) of unconsolidated affiliates										5	(2)	(1)
Income tax expense (benefit) from continuing operations										1,672	1,602	1,582
Segment income										3,040	2,819	2,714
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										6,649	6,852	4,642
Assets		114,993				109,097				114,993	109,097	104,119
Electric Utilities and Infrastructure [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										1,410	1,331	1,317
Interest expense										58	53	43
Depreciation and amortization										151	147	138
Income tax expense (benefit) from continuing operations										55	59	71
Segment income										154	118	122
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										322	264	193
Assets		4,782				4,534				4,782	4,534	4,428
Electric Utilities and Infrastructure [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(30)	(32)	(36)
Gas Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										875	536	573
Equity in earnings (losses) of unconsolidated affiliates										19	1	0
Gas Utilities and Infrastructure [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										901	541	578
Interest expense										46	25	37
Depreciation and amortization										115	79	73
Equity in earnings (losses) of unconsolidated affiliates										19	1
Income tax expense (benefit) from continuing operations										90	44	45
Segment income										152	73	80
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										5,519	234	121
Assets		10,760				2,637				10,760	2,637	2,512
Gas Utilities and Infrastructure [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										503	541	578
Interest expense										27	25	37
Depreciation and amortization										80	79	73
Income tax expense (benefit) from continuing operations										44	45	45
Segment income										77	73	80
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										154	135	107
Assets		2,696				2,516				2,696	2,516	2,487
Gas Utilities and Infrastructure [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(26)	(5)	(5)
Commercial Renewables [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										484	286	235
Equity in earnings (losses) of unconsolidated affiliates										(82)	(6)	8
Impairment charges										71
Commercial Renewables [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										484	286	236
Interest expense										53	44	50
Depreciation and amortization										130	104	90
Equity in earnings (losses) of unconsolidated affiliates										(82)	(6)	8
Income tax expense (benefit) from continuing operations										(160)	(128)	(88)
Segment income										23	52	53
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										857	1,019	514
Assets		4,377				3,861				4,377	3,861	2,981
Commercial Renewables [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues												(1)
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										22,695	22,311	22,463
Total Reportable Segments [Member] | Operating Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										22,751	22,348	22,505
Interest expense										1,235	1,143	1,144
Depreciation and amortization										3,142	2,918	2,849
Equity in earnings (losses) of unconsolidated affiliates										(58)	(7)	7
Income tax expense (benefit) from continuing operations										1,602	1,518	1,539
Segment income										3,215	2,944	2,847
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										13,025	8,105	5,277
Assets		130,130				115,595				130,130	115,595	109,612
Total Reportable Segments [Member] | Operating Segments [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										1,913	1,872	1,895
Interest expense										85	78	80
Depreciation and amortization										231	226	211
Income tax expense (benefit) from continuing operations										99	104	116
Segment income										231	191	202
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										476	399	300
Assets		7,478				7,050				7,478	7,050	6,915
Total Reportable Segments [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(56)	(37)	(42)
Other Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										48	60	46
Other Segment [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										(69)	(75)	(70)
Other Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										117	135	116
Interest expense										693	393	409
Depreciation and amortization										152	135	120
Equity in earnings (losses) of unconsolidated affiliates										43	76	123
Income tax expense (benefit) from continuing operations										(446)	(262)	(314)
Segment income										(645)	(299)	(332)
Costs to achieve mergers										329
Cost Savings Initiative, Net of tax										57
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										190	258	251
Assets		2,443				5,373				2,443	5,373	10,755
Other Segment [Member] | Corporate, Non-Segment [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues										31	33	19
Interest expense										1	1	5
Depreciation and amortization										2	1	3
Income tax expense (benefit) from continuing operations										(21)	(23)	(73)
Segment income										(39)	(41)	(133)
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions												22
Assets		$ 62				$ 56				62	56	3,321
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Equity in earnings (losses) of unconsolidated affiliates										43	76	123
Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Costs to achieve mergers											60
Cost Savings Initiative, Net of tax											77
Edwardsport IGCC Plant [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Litigation Settlement, Expense											58
Ohio Valley Electric Corporation [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges												94
Ohio Valley Electric Corporation [Member] | Other [Member] | Corporate, Non-Segment [Member] | Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges												94
Dan River [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Litigation Settlement, Expense												102
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges										194
International Energy [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information Assets [Abstract]
Capital investments, expenditures and acquisitions										26	$ 45	$ 67
Piedmont Natural Gas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Net Income (Loss) Attributable to Parent										$ 20
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000
Piedmont Natural Gas [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information Assets [Abstract]
Payments to Acquire Businesses, Gross	$ 5,000

Business Segments (Schedule of

Business Segments (Schedule of Revenue, By Products and Services) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Operating revenues	$ 5,577	$ 6,576	$ 5,213	$ 5,377	$ 5,075	$ 6,202	$ 5,302	$ 5,792	$ 22,743	$ 22,371	$ 22,509
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									21,336	21,489	21,655
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									875	536	573
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues									484	286	235
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues									22,695	22,311	22,463
Retail Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues									18,338	18,695	19,007
Retail Electric [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									18,338	18,695	19,007
Wholesale Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues									2,398	2,259	2,115
Wholesale Electric [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									2,095	2,014	1,879
Wholesale Electric [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues									303	245	236
Retail Natural Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues									871	546	571
Retail Natural Gas [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									871	546	571
Other Revenues [Member]
Segment Reporting Information [Line Items]
Operating revenues									1,144	848	812
Other Revenues [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									933	812	805
Other Revenues [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									30	(5)	7
Other Revenues [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues									181	41
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									21,366	21,521	21,691
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues									901	541	578
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues									484	286	236
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues									$ 22,751	$ 22,348	$ 22,505

Business Segments (Schedule o81

Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment income	$ 2,571	$ 2,645	$ 2,533
Duke Energy Carolinas [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(104)	(95)	(79)
Progress Energy [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(200)	(159)	(190)
Duke Energy Progress [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(56)	(32)	(31)
Duke Energy Florida [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(23)	(16)	(19)
Duke Energy Indiana [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	$ (13)	$ (10)	$ (11)

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details)	Jan. 03, 2017USD ($)	Oct. 19, 2016USD ($)	Oct. 03, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2016USD ($)MW	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jan. 17, 2017USD ($)	Jun. 30, 2016USD ($)	Sep. 02, 2014
Public Utilities, General Disclosures [Line Items]
Net Asset Percentage Limit						25.00%
Regulatory Assets, noncurrent				$ 11,373,000,000		$ 12,878,000,000	$ 11,373,000,000
Net property, plant and equipment				73,779,000,000		82,520,000,000	73,779,000,000
Impairment charges						18,000,000	106,000,000	$ 81,000,000
Debt Instrument, Face Amount				2,700,000,000		9,127,000,000	2,700,000,000
Regulated Revenue						21,221,000,000	21,379,000,000	21,550,000,000
Regulatory assets				12,250,000,000		$ 13,901,000,000	12,250,000,000
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						47.00%					40.00%
Long-term Purchase Commitment, Period						20 years
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						7.50%
Estimated capital cost						$ 3,200,000,000
Long-term Purchase Commitment, Period						25 years
Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						24.00%
Estimated Contributions For Pipeline And Construction Costs						$ 229,000,000
Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						9 years
Regulatory assets				2,151,000,000		$ 2,387,000,000	2,151,000,000
Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				509,000,000		534,000,000	509,000,000
NCEMPA deferrals [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				21,000,000		51,000,000	21,000,000
Nuclear asset securitized balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				1,237,000,000		1,193,000,000	1,237,000,000
Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				245,000,000		226,000,000	245,000,000
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						5,000,000,000
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						5,500,000,000
Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Approved Appeal Bond						98,000,000
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent				2,766,000,000		3,159,000,000	2,766,000,000
Net property, plant and equipment				25,877,000,000		26,762,000,000	25,877,000,000
Impairment charges						1,000,000	1,000,000	3,000,000
Debt Instrument, Face Amount				500,000,000		1,600,000,000	500,000,000
Regulatory assets				3,071,000,000		$ 3,397,000,000	3,071,000,000
Duke Energy Carolinas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Long-term Purchase Commitment, Period						20 years
Duke Energy Carolinas [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				479,000,000		$ 481,000,000	479,000,000
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				49,000,000		39,000,000	49,000,000
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				107,000,000		$ 92,000,000	107,000,000
Duke Energy Carolinas [Member] | Minimum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						1 year
Duke Energy Carolinas [Member] | Maximum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						6 years
Duke Energy Carolinas [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.20%
Duke Energy Carolinas [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage						8.49%
Duke Energy Carolinas [Member] | FERC ROE Settlement [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.00%
Duke Energy Carolinas [Member] | Advanced Metering Infrastructure Deferral [Member] | PSCSC [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent						$ 45,000,000
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member] | NCEMC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC						$ 600,000,000
Joint owner ownership percentage						13.00%
Duke Energy Carolinas [Member] | William State Lee III Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment						$ 520,000,000
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent				2,710,000,000		3,243,000,000	2,710,000,000
Net property, plant and equipment				17,720,000,000		18,387,000,000	17,720,000,000
Payments to Acquire Businesses, Gross							1,249,000,000
Impairment charges						1,000,000	5,000,000	(18,000,000)
Debt Instrument, Face Amount				1,200,000,000		450,000,000	1,200,000,000
Regulatory assets				2,974,000,000		$ 3,431,000,000	2,974,000,000
Duke Energy Progress [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Long-term Purchase Commitment, Period						20 years
Duke Energy Progress [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				366,000,000		$ 423,000,000	366,000,000
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						10 years
Regulatory assets				179,000,000		$ 165,000,000	179,000,000
Duke Energy Progress [Member] | NCEMPA deferrals [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						24 years
Regulatory assets				21,000,000		$ 51,000,000	21,000,000
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				62,000,000		$ 38,000,000	62,000,000
Duke Energy Progress [Member] | Maximum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						10 years
Duke Energy Progress [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.80%
Duke Energy Progress [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage						8.49%
Duke Energy Progress [Member] | FERC ROE Settlement [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.00%
Duke Energy Progress [Member] | Storm Cost Deferrals [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Deferred Storm and Property Reserve Deficiency, Noncurrent						$ 60,000,000
Duke Energy Progress [Member] | Storm Cost Deferrals [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Storm Costs - Capital and Operation Maintenance						$ 140,000,000
Duke Energy Progress [Member] | 2016 South Carolina Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						15 years
Duke Energy Progress [Member] | 2016 South Carolina Rate Case [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage						10.75%
Requested Rate Increase (Decrease), Percentage						14.50%
Requested Rate Increase (Decrease), Amount						$ 79,000,000
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission		10.10%
Approved rate increase (decrease) amount by state commission		$ 56,000,000
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 1 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission		38,000,000
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 2 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission		18,500,000
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 2 Offset [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission		$ (18,500,000)
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						1,100,000,000
Duke Energy Progress [Member] | FERC Mitigation [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges								(18,000,000)
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent						48,000,000
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent				2,725,000,000		2,480,000,000	2,725,000,000
Net property, plant and equipment				10,623,000,000		11,790,000,000	10,623,000,000
Impairment charges						6,000,000	7,000,000	2,000,000
Debt Instrument, Face Amount						1,894,000,000
Regulatory assets				2,823,000,000		2,693,000,000	2,823,000,000
Duke Energy Florida [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				441,000,000		458,000,000	441,000,000
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				230,000,000		257,000,000	230,000,000
Duke Energy Florida [Member] | Nuclear asset securitized balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				1,237,000,000		1,193,000,000	1,237,000,000
Duke Energy Florida [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				76,000,000		96,000,000	76,000,000
Duke Energy Florida [Member] | Hines Chiller Uprate Project [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						150,000,000
Duke Energy Florida [Member] | Hines Chiller Uprate Project Phase 1 [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount						17,000,000
Duke Energy Florida [Member] | Hines Chiller Uprate Project Phase 2 [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount						3,000,000
Duke Energy Florida [Member] | Osprey Energy Center Acquisition [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission						$ 48,000,000
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.50%
Approved rate increase (decrease) amount by state commission						$ 150,000,000
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						9.50%
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						11.50%
Duke Energy Florida [Member] | Citrus County Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC						$ 1,500,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						20 years
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | ISFSI Projects [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						7.35%
Regulatory Assets, noncurrent						$ 93,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member] | Original Uprate Project [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						7 years
Regulatory Assets, noncurrent						$ 128,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent				1,283,000,000			1,283,000,000
Amount of Regulatory Costs Not yet Approved						1,298,000,000
Impairment charges					$ 15,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission						$ 0
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						5 years
Regulatory Assets, noncurrent						$ 100,000,000
Net property, plant and equipment						119,000,000
Net unrecovered investment						$ 219,000,000
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Limit of Total Capital						30.00%
Regulatory Assets, noncurrent				497,000,000		$ 520,000,000	497,000,000
Net property, plant and equipment				5,243,000,000		5,547,000,000	5,243,000,000
Impairment charges								94,000,000
Debt Instrument, Face Amount						250,000,000
Regulated Revenue						1,410,000,000	1,331,000,000	$ 1,316,000,000
Regulatory assets				533,000,000		557,000,000	533,000,000
Duke Energy Ohio [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				139,000,000		135,000,000	139,000,000
Duke Energy Ohio [Member] | East Bend Coal Ash Basin Filing [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						93,000,000
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | PUCO [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC						86,000,000
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC						110,000,000
Duke Energy Ohio [Member] | Accelerated Natural Gas Service Line Replacement Rider | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved						240,000,000
Duke Energy Ohio [Member] | Energy Efficiency and Peak Demand Reduction Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulated Revenue				20,000,000
Duke Energy Ohio [Member] | Mgp Remediation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets						99,000,000
Duke Energy Ohio [Member] | Advanced Metering Infrastructure Project [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						49,000,000
Amount of Regulatory Costs Not yet Approved						10,000,000
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				72,000,000		$ 71,000,000	72,000,000
Approved MVP Proposals						17
MISO estimate of Duke Energy Ohio's MVP obligation						$ 2,700,000,000
Duke Energy Ohio [Member] | East End Site [Member] | Mgp Remediation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Environmental Exit Costs, Anticipated Cost						$ 46,000,000
Duke Energy Kentucky [Member]
Public Utilities, General Disclosures [Line Items]
Required Equity Capital Structure Percent						35.00%
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent				716,000,000		$ 1,073,000,000	716,000,000
Net property, plant and equipment				9,523,000,000		9,924,000,000	9,523,000,000
Impairment charges						8,000,000	88,000,000
Debt Instrument, Face Amount						500,000,000
Regulatory assets				818,000,000		1,222,000,000	818,000,000
Duke Energy Indiana [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				220,000,000		222,000,000	220,000,000
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				51,000,000		$ 73,000,000	51,000,000
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						12.38%
Approved Return on Equity Percentage Adder						0.50%
Duke Energy Indiana [Member] | Coal Combustion Residual Plan [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount						$ 380,000,000
Federal Mandate Costs Recovered Through Tracker Mechanism						80.00%
Federally Mandated Costs Recovered In Future Rate Case						20.00%
Percentage of Costs Recovered through Existing Rider						60.00%
Percentage Recovered Through Future Rate Case						40.00%
Long-term Debt Rate						4.73%
Requested Rate Increase (Decrease), Amended, Amount						$ 365,000,000
Duke Energy Indiana [Member] | FERC Complaint 1 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.32%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage						8.67%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage						9.70%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost						$ 1,900,000,000
Duke Energy Indiana [Member] | Revised Grid Infrastructure Improvement Plan [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission						10.00%
Approved rate increase (decrease) amount by state commission						$ 1,400,000,000
Estimated capital cost						1,800,000,000
Duke Energy Indiana [Member] | Advanced Metering Infrastructure Project [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment						46,000,000
Impairment charges						$ 8,000,000
Duke Energy Indiana [Member] | Edwardsport IGCC Plant [Member] | IGCC Rider Proceeding [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period						8 years
Regulatory assets						$ 161,000,000
Requested Rate Increase (Decrease), Amended, Amount						(87,500,000)
Legal Fees						$ 5,500,000
Utilities Operating Expense, Other							93,000,000
Dominion Resources [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						48.00%					45.00%
Piedmont Natural Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage											10.00%
Ownership Interest in Jointly Owned Plant Transferred			3.00%
Proceeds from Divestiture of Businesses and Interests in Affiliates			$ 14,000,000
Southern Company Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						5.00%					5.00%
Spectra Energy [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						50.00%
NextEra [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						42.50%
Williams Partners L.P. [Member] | Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage						41.00%
Subsequent Event [Member] | Duke Energy Florida [Member] | Osprey Energy Center Acquisition [Member]
Public Utilities, General Disclosures [Line Items]
Payments to Acquire Businesses, Gross	$ 166,000,000
Subsequent Event [Member] | Duke Energy Florida [Member] | Osprey Energy Center Acquisition [Member] | USDOJ [Member]
Public Utilities, General Disclosures [Line Items]
Other Commitment									$ 600,000
DEFPF [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, noncurrent						$ 1,142,000,000
Debt Instrument, Face Amount						1,294,000,000
DEFPF [Member] | Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount										$ 1,294,000,000
Proceeds from Issuance of Debt						1,287,000,000
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment						$ 424,000,000
Capacity (in MW) | MW						1,738
Generation Facilities To Be Retired [Member] | Duke Energy Progress [Member] | Asheville Plant [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment				$ 548,000,000		$ 492,000,000	$ 548,000,000
Capacity (in MW) | MW						376

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 13,901	$ 12,250
Regulatory Assets, Current	1,023	877
Regulatory Assets, noncurrent	12,878	11,373
Regulatory liabilities	7,290	6,655
Regulatory liabilities - current	409	400
Regulatory liabilities, noncurrent	6,881	6,255
Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	6,074	5,329
Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	45	71
Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	83	150
Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	174	288
Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	192	311
Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	722	506
Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	3,761	2,555
Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	684	838
Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,387	2,151
Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	534	509
Debt Fair Value Adjustment [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,313	1,191
Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	894	1,075
Storm Costs Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	153
Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,193	1,237
Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	217	571
Derivatives - gas supply contracts [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	187
Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	407	340
Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	65	68
Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	196	192
Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	156	151
Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	226	245
Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	413	383
Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	8	32
Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	71	72
Manufactured Gas Plant [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	99	104
Advanced Metering Infrastructure [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	218
NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	51	21
East Bend deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	32	16
Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	636	499
Duke Energy Carolinas [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	3,397	3,071
Regulatory Assets, Current	238	305
Regulatory Assets, noncurrent	3,159	2,766
Regulatory liabilities	3,001	2,841
Regulatory liabilities - current	161	39
Regulatory liabilities, noncurrent	2,840	2,802
Duke Energy Carolinas [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	2,476	2,413
Duke Energy Carolinas [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	22	24
Duke Energy Carolinas [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	46	68
Duke Energy Carolinas [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	105	55
Duke Energy Carolinas [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	352	281
Duke Energy Carolinas [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,536	1,120
Duke Energy Carolinas [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	9	104
Duke Energy Carolinas [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	481	479
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	39	49
Duke Energy Carolinas [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	484	564
Duke Energy Carolinas [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	93	127
Duke Energy Carolinas [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	122	80
Duke Energy Carolinas [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	76	79
Duke Energy Carolinas [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets		21
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	92	107
Duke Energy Carolinas [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	70	97
Duke Energy Carolinas [Member] | Advanced Metering Infrastructure [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	172
Duke Energy Carolinas [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	223	244
Progress Energy [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	6,123	5,797
Regulatory Assets, Current	401	362
Regulatory Assets, noncurrent	5,722	5,435
Regulatory liabilities	2,584	2,673
Regulatory liabilities - current	189	286
Regulatory liabilities, noncurrent	2,395	2,387
Progress Energy [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	2,198	2,078
Progress Energy [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	60	125
Progress Energy [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		51
Progress Energy [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	81	255
Progress Energy [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	245	164
Progress Energy [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,830	1,394
Progress Energy [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	569	487
Progress Energy [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	882	807
Progress Energy [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	422	409
Progress Energy [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	231	318
Progress Energy [Member] | Storm Costs Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	148
Progress Energy [Member] | Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,193	1,237
Progress Energy [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	91	410
Progress Energy [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	278	250
Progress Energy [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	38
Progress Energy [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	111	129
Progress Energy [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	134	138
Progress Energy [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	42	38
Progress Energy [Member] | NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	51	21
Progress Energy [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	103	121
Duke Energy Progress [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	3,431	2,974
Regulatory Assets, Current	188	264
Regulatory Assets, noncurrent	3,243	2,710
Regulatory liabilities	2,104	1,963
Regulatory liabilities - current	158	85
Regulatory liabilities, noncurrent	1,946	1,878
Duke Energy Progress [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1,840	1,725
Duke Energy Progress [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		25
Duke Energy Progress [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	64	58
Duke Energy Progress [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	200	155
Duke Energy Progress [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,822	1,386
Duke Energy Progress [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	275	195
Duke Energy Progress [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	423	366
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	165	179
Duke Energy Progress [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	7	106
Duke Energy Progress [Member] | Storm Costs Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	148
Duke Energy Progress [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	66	171
Duke Energy Progress [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	263	237
Duke Energy Progress [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	38
Duke Energy Progress [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	24	93
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	62
Duke Energy Progress [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	42	38
Duke Energy Progress [Member] | NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	51	21
Duke Energy Progress [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	69	82
Duke Energy Florida [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,693	2,823
Regulatory Assets, Current	213	98
Regulatory Assets, noncurrent	2,480	2,725
Regulatory liabilities	479	709
Regulatory liabilities - current	31	200
Regulatory liabilities, noncurrent	448	509
Duke Energy Florida [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	358	353
Duke Energy Florida [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	60	125
Duke Energy Florida [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		26
Duke Energy Florida [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	17	197
Duke Energy Florida [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	44	8
Duke Energy Florida [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	8	8
Duke Energy Florida [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	294	292
Duke Energy Florida [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	458	441
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	257	230
Duke Energy Florida [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	224	212
Duke Energy Florida [Member] | Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,193	1,237
Duke Energy Florida [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	25	239
Duke Energy Florida [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	15	13
Duke Energy Florida [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	87	36
Duke Energy Florida [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	96	76
Duke Energy Florida [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	36	39
Duke Energy Ohio [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	557	533
Regulatory Assets, Current	37	36
Regulatory Assets, noncurrent	520	497
Regulatory liabilities	257	257
Regulatory liabilities - current	21	12
Regulatory liabilities, noncurrent	236	245
Duke Energy Ohio [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	212	222
Duke Energy Ohio [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1	1
Duke Energy Ohio [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	19	21
Duke Energy Ohio [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	6	1
Duke Energy Ohio [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	19	12
Duke Energy Ohio [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	12	4
Duke Energy Ohio [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	135	139
Duke Energy Ohio [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	63	55
Duke Energy Ohio [Member] | Storm Costs Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5
Duke Energy Ohio [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	7	7
Duke Energy Ohio [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	6	10
Duke Energy Ohio [Member] | Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	65	68
Duke Energy Ohio [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	4	5
Duke Energy Ohio [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5	1
Duke Energy Ohio [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	20	21
Duke Energy Ohio [Member] | Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	71	72
Duke Energy Ohio [Member] | Manufactured Gas Plant [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	99	104
Duke Energy Ohio [Member] | East Bend deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	32	16
Duke Energy Ohio [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	33	31
Duke Energy Indiana [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,222	818
Regulatory Assets, Current	149	102
Regulatory Assets, noncurrent	1,073	716
Regulatory liabilities	788	816
Regulatory liabilities - current	40	62
Regulatory liabilities, noncurrent	748	754
Duke Energy Indiana [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	660	616
Duke Energy Indiana [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	45	71
Duke Energy Indiana [Member] | Accrued Pension And OPEB [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	72	83
Duke Energy Indiana [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	11	46
Duke Energy Indiana [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	276	37
Duke Energy Indiana [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	222	220
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	73	51
Duke Energy Indiana [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	119	120
Duke Energy Indiana [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	26	27
Duke Energy Indiana [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	10	10
Duke Energy Indiana [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	40
Duke Energy Indiana [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	281	227
Duke Energy Indiana [Member] | Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	8	32
Duke Energy Indiana [Member] | Advanced Metering Infrastructure [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	46
Duke Energy Indiana [Member] | Other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 121	$ 94

Regulatory Matters (Schedule 84

Regulatory Matters (Schedule of MISO Exit fees)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 136
Provision/adjustments	110
Cash reductions	(167)
Balance, end of period	79
Total regulatory assets	13,901	$ 12,250
Duke Energy Ohio [Member]
Restructuring Reserve [Roll Forward]
Total regulatory assets	557	533
Duke Energy Ohio [Member] | RTO Realignment [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	92
Provision/adjustments	3
Cash reductions	(5)
Balance, end of period	90
Total regulatory assets	$ 71	$ 72

Regulatory Matters (Schedule 85

Regulatory Matters (Schedule of Net Carrying Value Of Facilities) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)MW	Dec. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory assets	$ 13,901	$ 12,250
Net property, plant and equipment	82,520	73,779
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets	3,397	3,071
Net property, plant and equipment	26,762	25,877
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets	6,123	5,797
Net property, plant and equipment	30,181	28,347
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets	2,693	2,823
Net property, plant and equipment	11,790	10,623
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets	1,222	818
Net property, plant and equipment	9,924	9,523
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets	3,431	2,974
Net property, plant and equipment	$ 18,387	$ 17,720
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,738
Net property, plant and equipment	$ 424
Generation Facilities To Be Retired [Member] | Duke Energy Carolinas [Member] | Allen Steam Station Units 1-3 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Net property, plant and equipment	$ 168
Generation Facilities To Be Retired [Member] | Progress Energy [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Net property, plant and equipment	$ 120
Generation Facilities To Be Retired [Member] | Duke Energy Florida [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Net property, plant and equipment	$ 120
Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member] | Gallagher Units 2 and 4 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Net property, plant and equipment	$ 136

Commitments and Contingencies86

Commitments and Contingencies (Narrative) (Details)	Sep. 29, 2016USD ($)	Sep. 23, 2016USD ($)	Feb. 08, 2016USD ($)	Apr. 22, 2015USD ($)	Mar. 10, 2015USD ($)	Feb. 20, 2015USD ($)	Dec. 31, 2016USD ($)plantClaimsreactor	Dec. 31, 2016USD ($)plantClaimsreactor	Dec. 31, 2016USD ($)plantClaimsreactor	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Aug. 18, 2014gal	Mar. 31, 2014USD ($)	Feb. 28, 2014galT
Insurance [Abstract]
Insured public liability limit per nuclear incident							$ 13,400,000,000	$ 13,400,000,000	$ 13,400,000,000
Excess nuclear liability program coverage							13,000,000,000	13,000,000,000	13,000,000,000
Pro rata assessment for each reactor owned for each incident exceeding public liability insurance							$ 127,000,000	$ 127,000,000	$ 127,000,000
Number of licensed nuclear reactors | reactor							102	102	102
Annual payment limit to pro rata assessments							$ 19,000,000	$ 19,000,000	$ 19,000,000
Industry aggregate limit							3,200,000,000	3,200,000,000	3,200,000,000
Sublimit for non-nuclear terrorist events							$ 1,830,000,000	$ 1,830,000,000	$ 1,830,000,000
Insurance Coverage Percentage Initial Weeks							100.00%	100.00%	100.00%
Accidental Outage Insurance Coverage Initial Weeks									365 days
Insurance Coverage Percentage Additional Weeks							80.00%	80.00%	80.00%
Accidental Outage Insurance Coverage Additional Weeks									770 days
Weeks of Sublimits for Accidental Outage Coverage									728 days
Sublimit accidental outage recovery							$ 328,000,000	$ 328,000,000	$ 328,000,000
Maximum Magnitude of Retroactive Premiums							10	10	10
Maximum Period for Retroactive Premium Assessment									6 years
North Carolina Ash Basins [Member]
Valuation and Qualifying Accounts [Abstract]
Facilities with Ash Basins | plant							14	14	14
Progress Energy Merger Shareholder Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Amount					$ 146,000,000
Payments for Legal Settlements				$ 25,000,000
Litigation Settlement Covered by Insurance				$ 121,000,000
Gain contingency, unrecorded amount							$ 27,000,000	$ 27,000,000	$ 27,000,000
NCDEQ State Enforcement Actions [Member]
Valuation and Qualifying Accounts [Abstract]
Number of Plants with No Disputed Facts | plant							7	7	7
Facilities with Ash Basins | plant							14	14	14
Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Facilities with Ash Basins | plant							14	14	14
Goodwill Payment							$ 5,000	$ 5,000	$ 5,000
Water Bill Stipend Period									25 years
Ash Basins Fines and Restitution [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense						$ 68,000,000
Ash Basins Community Service and Mitigation [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense						$ 34,000,000
Duke Energy Carolinas [Member]
Insurance [Abstract]
Primary nuclear liability program coverage							375,000,000	375,000,000	$ 375,000,000
Primary Nuclear Liability Coverage after January 2017									450,000,000
Max Retroactive Premium Assessments									164,000,000
Duke Energy Carolinas [Member] | McGuire Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							1,500,000,000	1,500,000,000	1,500,000,000
Additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Accidental outage insurance coverage policy limit							490,000,000	490,000,000	490,000,000
Duke Energy Carolinas [Member] | Catawba Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							1,500,000,000	1,500,000,000	1,500,000,000
Dedicated additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Additional Non Nuclear Accident Limit							750,000,000	750,000,000	750,000,000
Accidental outage insurance coverage policy limit							$ 490,000,000	$ 490,000,000	$ 490,000,000
Potential Obligation percentage							100.00%	100.00%	100.00%
Duke Energy Carolinas [Member] | Oconee Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							$ 1,500,000,000	$ 1,500,000,000	$ 1,500,000,000
Additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Additional Non Nuclear Accident Limit							750,000,000	750,000,000	750,000,000
Accidental outage insurance coverage policy limit							464,000,000	464,000,000	464,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance required							250,000,000	250,000,000	250,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Amount		$ (6,000,000)
Civil Penalty Assessed			$ 6,800,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member] | Minimum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated amount of ash released, in tons | T														30,000
Estimated amount of ash basin water released, in gallons | gal														24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member] | Maximum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated amount of ash released, in tons | T														39,000
Estimated amount of ash basin water released, in gallons | gal														27,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Operating Expense [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense											$ 72,000,000
Duke Energy Carolinas [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement									1,000,000
Duke Energy Carolinas [Member] | Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Settlement Offer Expense							18,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves							512,000,000	512,000,000	512,000,000	$ 536,000,000
Reinsurance retention policy, excess retention, amount reinsured									814,000,000
Probable insurance recoveries							$ 587,000,000	$ 587,000,000	$ 587,000,000	599,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims							121	121	121
Asbestos-related injuries and damages reserves							$ 32,000,000	$ 32,000,000	$ 32,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims							58	58	58
Asbestos-related injuries and damages reserves							$ 16,000,000	$ 16,000,000	$ 16,000,000
Duke Energy Progress [Member]
Insurance [Abstract]
Primary nuclear liability program coverage							375,000,000	375,000,000	375,000,000
Primary Nuclear Liability Coverage after January 2017									450,000,000
Max Retroactive Premium Assessments									104,000,000
Duke Energy Progress [Member] | Robinson Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							1,500,000,000	1,500,000,000	1,500,000,000
Additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Accidental outage insurance coverage policy limit							404,000,000	404,000,000	404,000,000
Duke Energy Progress [Member] | Brunswick Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							1,500,000,000	1,500,000,000	1,500,000,000
Additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Accidental outage insurance coverage policy limit							490,000,000	490,000,000	490,000,000
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Insurance [Abstract]
Sublimit property damage losses							1,500,000,000	1,500,000,000	1,500,000,000
Additional nuclear accident limit							1,250,000,000	1,250,000,000	1,250,000,000
Accidental outage insurance coverage policy limit							490,000,000	490,000,000	490,000,000
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance required							250,000,000	250,000,000	250,000,000
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | Operating Expense [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense											$ 30,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement									6,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed					$ 25,000,000
Duke Energy Progress [Member] | Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Settlement Offer Expense							4,000,000
Duke Energy Progress [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount							48,000,000	48,000,000	48,000,000
Duke Energy Florida [Member]
Insurance [Abstract]
Primary nuclear liability program coverage							375,000,000	375,000,000	375,000,000
Primary Nuclear Liability Coverage after January 2017									450,000,000
Max Retroactive Premium Assessments									1,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Insurance [Abstract]
Sublimit property damage losses							$ 50,000,000	$ 50,000,000	$ 50,000,000
Potential Obligation percentage							100.00%	100.00%	100.00%
Duke Energy Florida [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount							$ 25,000,000	$ 25,000,000	$ 25,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount							54,000,000	54,000,000	54,000,000
Loss Contingency, Damages Sought, Original Amount							482,000,000	482,000,000	482,000,000				$ 510,000,000
Loss Contingency, Damages Awarded, Value	$ 30,000,000								30,000,000
Gain Contingency, Dismissed Amount	$ 54,000,000
Loss contingency, damages sought, value									424,000,000
Loss Contingency Damages Awarded and Interest, Value							$ 34,000,000
Duke Energy Florida [Member] | MGP Cost Recovery Action [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, damages sought, value									43,000,000
Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Amount										81,000,000
Litigation Settlement, Expense										$ 81,000,000
Duke Energy Ohio [Member] | W.C. Beckjord Fuel Release [Member] | W.C. Beckjord Station [Member]
Valuation and Qualifying Accounts [Abstract]
Gallons of Fuel Released | gal												9,000
Environmental Fine								1,000,000
Required Charitable Contribution								$ 100,000
Remediation Expense Reimbursed									1,000,000
Duke Energy Indiana [Member] | Benton County Wind Farm Dispute [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, damages sought, value									$ 16,000,000

Commitments and Contingencies87

Commitments and Contingencies (Schedule of Environmental Loss Contingencies)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 94	$ 92	$ 74
Provision/adjustments	19	11	32
Cash reductions	(15)	(9)	(14)
Ending balance	98	94	92
Duke Energy Carolinas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	10	11
Provision/adjustments	4	1	(1)
Cash reductions	(4)	(1)
Ending balance	10	10	10
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	17	27
Provision/adjustments	7	4	1
Cash reductions	(6)	(4)	(11)
Ending balance	18	17	17
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	3	5	8
Provision/adjustments	2		4
Cash reductions	(2)	(2)	(7)
Ending balance	3	3	5
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	14	12	19
Provision/adjustments	4	4	(3)
Cash reductions	(4)	(2)	(4)
Ending balance	14	14	12
Duke Energy Ohio [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	54	54	27
Provision/adjustments	7	1	28
Cash reductions	(2)	(1)	(1)
Ending balance	59	54	54
Duke Energy Indiana [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	12	10	7
Provision/adjustments	1	5	4
Cash reductions	(3)	(3)	(1)
Ending balance	10	$ 12	$ 10
Environmental Reserves [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	69
Environmental Reserves [Member] | Duke Energy Carolinas [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	22
Environmental Reserves [Member] | Duke Energy Ohio [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	36
Environmental Reserves [Member] | Duke Energy Indiana [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 7

Commitments and Contingencies88

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Legal Reserves Details [Line Items]
Reserves for legal matters	$ 98	$ 156
Duke Energy Carolinas [Member]
Legal Reserves Details [Line Items]
Reserves for legal matters	23	11
Progress Energy [Member]
Legal Reserves Details [Line Items]
Reserves for legal matters	59	54
Duke Energy Progress [Member]
Legal Reserves Details [Line Items]
Reserves for legal matters	14	6
Duke Energy Florida [Member]
Legal Reserves Details [Line Items]
Reserves for legal matters	28	31
Duke Energy Ohio [Member]
Legal Reserves Details [Line Items]
Reserves for legal matters	$ 4	$ 80

Commitments and Contingencies89

Commitments and Contingencies (PurchPower)(Details) - Public Utilities Purchased Power [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Duke Energy Progress [Member]
Unconditional Purchase Obligations [Abstract]
2,017	$ 66
2,018	67
2,019	67
2,020	50
2,021	51
Thereafter	267
Total	$ 568
Duke Energy Progress [Member] | Minimum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2,019
Long-term contract for purchase of electric power, share of plant output being purchased	15.00%
Duke Energy Progress [Member] | Maximum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2,031
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Duke Energy Florida [Member]
Unconditional Purchase Obligations [Abstract]
2,017	$ 341
2,018	357
2,019	377
2,020	394
2,021	376
Thereafter	1,211
Total	$ 3,056
Duke Energy Florida [Member] | Minimum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2,021
Long-term contract for purchase of electric power, share of plant output being purchased	81.00%
Duke Energy Florida [Member] | Maximum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2,043
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Duke Energy Ohio [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, date of contract expiration	2,018
2,017	$ 203
2,018	89
Total	$ 292
Duke Energy Ohio [Member] | Minimum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, share of plant output being purchased	1.00%
Duke Energy Ohio [Member] | Maximum [Member]
Unconditional Purchase Obligations [Abstract]
Long-term contract for purchase of electric power, share of plant output being purchased	11.00%

Commitments and Contingencies90

Commitments and Contingencies (Gas Supply Contracts) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Natural Gas Supply and Capacity Contracts [Member]
Long-term Purchase Commitment [Line Items]
2,017	$ 371
2,018	308
2,019	286
2,020	269
2,021	267
Thereafter	1,595
Total	$ 3,096
Maximum [Member] | Pipeline and Storage Capacity Contracts [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	19 years
Maximum [Member] | Natural Gas Supply Contract Fixed Payments [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	3 years
Maximum [Member] | Natural Gas Supply Contract Commitment [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	15 years
Duke Energy Ohio [Member] | Natural Gas Supply and Capacity Contracts [Member]
Long-term Purchase Commitment [Line Items]
2,017	$ 52
2,018	35
2,019	26
2,020	22
2,021	22
Thereafter	7
Total	$ 164
Duke Energy Ohio [Member] | Maximum [Member] | Pipeline and Storage Capacity Contracts [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	19 years
Duke Energy Ohio [Member] | Maximum [Member] | Natural Gas Supply Contract Fixed Payments [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	3 years
Duke Energy Ohio [Member] | Maximum [Member] | Natural Gas Supply Contract Commitment [Member]
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Period	15 years

Commitments and Contingencies91

Commitments and Contingencies (Future Minimum Payments for Operating and Capital Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets
Rental expense on operating leases	$ 242	$ 313	$ 350
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	218
2,018	205
2,019	181
2,020	164
2,021	134
Thereafter	948
Total future minimum lease payments	1,850
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	148
2,018	154
2,019	154
2,020	159
2,021	163
Thereafter	784
Minimum annual payments	1,562
Less amount representing interest	(462)
Total	1,100
Duke Energy Carolinas [Member]
Operating Leased Assets
Rental expense on operating leases	45	41	41
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	41
2,018	35
2,019	27
2,020	23
2,021	17
Thereafter	52
Total future minimum lease payments	195
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	6
2,018	6
2,019	6
2,020	5
2,021	1
Thereafter	30
Minimum annual payments	54
Less amount representing interest	(32)
Total	22
Progress Energy [Member]
Operating Leased Assets
Rental expense on operating leases	140	230	257
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	129
2,018	126
2,019	120
2,020	109
2,021	91
Thereafter	602
Total future minimum lease payments	1,177
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	46
2,018	46
2,019	45
2,020	46
2,021	45
Thereafter	322
Minimum annual payments	550
Less amount representing interest	(265)
Total	285
Duke Energy Progress [Member]
Operating Leased Assets
Rental expense on operating leases	68	149	161
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	75
2,018	73
2,019	68
2,020	58
2,021	43
Thereafter	379
Total future minimum lease payments	696
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	21
2,018	21
2,019	20
2,020	22
2,021	20
Thereafter	250
Minimum annual payments	354
Less amount representing interest	(212)
Total	142
Duke Energy Florida [Member]
Operating Leased Assets
Rental expense on operating leases	72	81	96
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	54
2,018	53
2,019	52
2,020	51
2,021	48
Thereafter	223
Total future minimum lease payments	481
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	25
2,018	25
2,019	25
2,020	25
2,021	25
Thereafter	71
Minimum annual payments	196
Less amount representing interest	(53)
Total	143
Duke Energy Ohio [Member]
Operating Leased Assets
Rental expense on operating leases	16	13	17
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	12
2,018	11
2,019	7
2,020	6
2,021	4
Thereafter	7
Total future minimum lease payments	47
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	4
2,018	3
2,019	1
Minimum annual payments	8
Less amount representing interest	(1)
Total	7
Duke Energy Indiana [Member]
Operating Leased Assets
Rental expense on operating leases	23	$ 20	$ 21
Operating Leases, Future Minimum Payments Due [Abstract]
2,017	20
2,018	17
2,019	11
2,020	10
2,021	6
Thereafter	9
Total future minimum lease payments	73
Capital Leases, Future Minimum Payments Due [Abstract]
2,017	1
2,018	2
2,019	1
2,020	1
2,021	1
Thereafter	41
Minimum annual payments	47
Less amount representing interest	(36)
Total	$ 11

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jan. 31, 2017	Aug. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Aug. 01, 2016	Jun. 01, 2016
Debt Instrument [Line Items]
Debt issuances			$ 9,127,000,000	$ 2,700,000,000
Other Debt Matters [Abstract]
Demand notes, maximum amount available for sale			3,000,000,000
Demand notes, maximum amount outstanding			1,500,000,000
Principal amount of demand notes			1,090,000,000	1,121,000,000
Subsidiary debt guaranteed by parent			762,000,000	767,000,000
Other Loans [Abstract]
Other loans outstanding against cash surrender value of life insurance policies			$ 661,000,000	629,000,000
Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Master Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 7,500,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			8,350,000,000
August 2016 Term Loan Facility [Member]
Debt Instrument [Line Items]
Facility Size							$ 1,500,000,000
Term Loan Proceeds			750,000,000
Repayments of Debt			$ 1,500,000,000
Secured Debt [Member] | Solar Facilities Financing [Member]
Debt Instrument [Line Items]
Debt issuances							333,000,000
Fixed credit spread		1.75%
Debt Instrument, Interest Rate, Increase (Decrease)		0.125%
August 2016 Debt Tranche A Maturing June 2034 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Interest rate			2.747%
Debt issuances			$ 228,000,000
August 2016 Debt Tranche A Maturing June 2034 [Member] | Secured Debt [Member] | Solar Facilities Financing [Member]
Debt Instrument [Line Items]
Debt issuances							228,000,000
August 2016 Debt Tranche B Maturing June 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Interest rate			2.747%
Debt issuances			$ 105,000,000
August 2016 Debt Tranche B Maturing June 2020 [Member] | Secured Debt [Member] | Solar Facilities Financing [Member]
Debt Instrument [Line Items]
Debt issuances							105,000,000
May 2016 Debt Maturing May 2046 [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
Debt issuances			$ 500,000,000
Repayments of Debt			325,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances			1,600,000,000	500,000,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid			$ 2,000,000,000	401,000,000	$ 500,000,000
Duke Energy Carolinas [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 1,100,000,000
Progress Energy [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances			$ 450,000,000	1,200,000,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid			300,000,000
Other Loans [Abstract]
Other loans outstanding against cash surrender value of life insurance policies			$ 39,000,000	41,000,000
Duke Energy Progress [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 1,000,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances			1,894,000,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid			$ 775,000,000	$ 350,000,000
Duke Energy Florida [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 950,000,000
Duke Energy Florida [Member] | Subsequent Event [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Debt issuances	$ 900,000,000
Duke Energy Florida [Member] | Subsequent Event [Member] | January 2017 Debt Issuance 1 [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Debt issuances	250,000,000
Repayments of Debt	250,000,000
Duke Energy Florida [Member] | Subsequent Event [Member] | January 2017 Debt Issuance 2 [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Debt issuances	$ 650,000,000
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances			$ 250,000,000
Duke Energy Ohio [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 450,000,000
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt issuances			500,000,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid			$ 149,000,000
Duke Energy Indiana [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.65
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 600,000,000
Duke Energy Indiana [Member] | May 2016 Debt Maturing May 2046 [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
Debt issuances			$ 500,000,000
Repayments of Debt			$ 325,000,000
Piedmont Natural Gas [Member] | Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower			0.70
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 850,000,000
Line Of Credit Facility Optional Additional Expansion Amount			200,000,000
Line of Credit Facility, Current Borrowing Capacity			10,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility Size							4,900,000,000
Piedmont Natural Gas [Member] | August 2016 Term Loan Facility [Member]
Debt Instrument [Line Items]
Facility Size						$ 1,500,000,000
Term Loan Proceeds			750,000,000			$ 750,000,000
Piedmont Natural Gas [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances							$ 3,750,000,000
Swap [Member] | August 2016 Debt Tranche A Maturing June 2034 [Member] | Secured Debt [Member] | Solar Facilities Financing [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate							1.81%
Swap [Member] | August 2016 Debt Tranche B Maturing June 2020 [Member] | Secured Debt [Member] | Solar Facilities Financing [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate							1.38%
DEFPF [Member] | Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances			1,294,000,000
DEFPF [Member] | Duke Energy Florida [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances								$ 1,294,000,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid			649,000,000
USDOJ [Member] | North Carolina Ash Basins [Member] | Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required			250,000,000
USDOJ [Member] | North Carolina Ash Basins [Member] | Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required			250,000,000
USDOJ [Member] | North Carolina Ash Basins [Member] | Duke Energy Progress [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required			250,000,000
USDOJ [Member] | North Carolina Ash Basins [Member] | Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required			$ 250,000,000

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Unsecured Debt	$ 17,812	$ 12,960
Secured Debt	3,909	2,361
First mortgage bonds	21,879	18,980
Capital leases	1,100	1,335
Tax exempt bonds	1,053	1,053
Notes payable and commercial paper	3,112	4,258
Fair value hedge carrying value adjustment	6	6
Unamortized debt discount and premium, net	1,753	1,712
Unamortized debt issuance costs	(17)	(43)
Total debt	50,382	42,501
Short-term notes payable and commercial paper	(2,487)	(3,633)
Current maturities of long-term debt	(2,319)	(2,026)
Total long-term debt	45,576	36,842
Short term obligations classified as long-term debt	$ 972	$ 972
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Maturity Date Range, End	Dec. 31, 2073	Dec. 31, 2073
Weighted-average rate	4.30%	4.68%
Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Maturity Date Range, End	Dec. 31, 2037	Dec. 31, 2037
Weighted-average rate	2.60%	2.37%
First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Maturity Date Range, End	Dec. 31, 2046	Dec. 31, 2045
Weighted-average rate	4.61%	4.74%
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2018	Dec. 31, 2016
Debt Instrument, Maturity Date Range, End	Dec. 31, 2051	Dec. 31, 2051
Weighted-average rate	4.48%	5.39%
Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2017	Dec. 31, 2017
Debt Instrument, Maturity Date Range, End	Dec. 31, 2041	Dec. 31, 2041
Weighted-average rate	2.84%	2.59%
Short term obligations classified as long-term debt	$ 347	$ 347
Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 625	$ 625
Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Weighted-average rate	1.01%	0.88%
Short term obligations classified as long-term debt	$ 625	$ 625
Weighted Average Days to Maturity	14 days	15 days
Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (242)	$ (164)
Weighted-average rate	4.07%	4.15%
Parent Company [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 53	$ 59
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,150	1,152
Secured Debt	425	425
First mortgage bonds	7,410	6,161
Capital leases	22	24
Tax exempt bonds	355	355
Money pool borrowings	300	300
Fair value hedge carrying value adjustment	6	6
Unamortized debt discount and premium, net	(20)	(17)
Unamortized debt issuance costs	(3)	(4)
Total debt	9,603	8,367
Current maturities of long-term debt	(116)	(356)
Total long-term debt	9,487	8,011
Short term obligations classified as long-term debt	335	335
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	35	35
Duke Energy Carolinas [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Duke Energy Carolinas [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(45)	(39)
Progress Energy [Member]
Debt Instrument [Line Items]
Unsecured Debt	3,551	3,850
Secured Debt	1,819	479
First mortgage bonds	10,800	9,750
Capital leases	285	300
Tax exempt bonds	48	48
Money pool borrowings	1,902	1,458
Unamortized debt discount and premium, net	(31)	(28)
Unamortized debt issuance costs	(4)	(5)
Total debt	18,270	15,772
Short-term money pool borrowings	(729)	(1,308)
Current maturities of long-term debt	(778)	(315)
Total long-term debt	16,763	14,149
Progress Energy [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(104)	(85)
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Secured Debt	300	254
First mortgage bonds	6,425	5,975
Capital leases	142	144
Tax exempt bonds	48	48
Money pool borrowings	150	359
Unamortized debt discount and premium, net	(16)	(16)
Unamortized debt issuance costs	(2)	(3)
Total debt	7,011	6,727
Short-term money pool borrowings	0	(209)
Current maturities of long-term debt	(452)	(2)
Total long-term debt	6,559	6,516
Short term obligations classified as long-term debt	150	150
Duke Energy Progress [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Progress [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	98	114
Duke Energy Progress [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(38)	(37)
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Unsecured Debt	150	150
Secured Debt	1,519	225
First mortgage bonds	4,375	3,775
Capital leases	143	156
Money pool borrowings	297	813
Unamortized debt discount and premium, net	(10)	(8)
Unamortized debt issuance costs	(2)	(2)
Total debt	6,422	5,079
Short-term money pool borrowings	(297)	(813)
Current maturities of long-term debt	(326)	(13)
Total long-term debt	5,799	4,253
Duke Energy Florida [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	670	731
Duke Energy Florida [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (52)	(32)
Piedmont Natural Gas [Member] | Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Weighted Average Days to Maturity	8 days
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Unsecured Debt	$ 810	765
First mortgage bonds	1,000	750
Capital leases	7	13
Tax exempt bonds	77	77
Money pool borrowings	41	128
Unamortized debt discount and premium, net	(28)	(28)
Unamortized debt issuance costs	(2)	(2)
Total debt	1,900	1,701
Short-term money pool borrowings	(16)	(103)
Current maturities of long-term debt	(1)	(106)
Total long-term debt	1,883	1,492
Short term obligations classified as long-term debt	52	52
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27	27
Duke Energy Ohio [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25	25
Duke Energy Ohio [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(7)	(4)
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Unsecured Debt	415	740
First mortgage bonds	2,669	2,319
Capital leases	11	14
Tax exempt bonds	572	572
Money pool borrowings	150	150
Unamortized debt discount and premium, net	(9)	(8)
Unamortized debt issuance costs	(2)	(2)
Total debt	3,786	3,768
Short-term money pool borrowings		0
Current maturities of long-term debt	(3)	(547)
Total long-term debt	3,783	3,221
Short term obligations classified as long-term debt	435	435
Duke Energy Indiana [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	285	285
Duke Energy Indiana [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Indiana [Member] | Total Debt And Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	(22)	(19)
International Energy [Member] | Progress Energy [Member]
Debt Instrument [Line Items]
Money pool borrowings	1,000
Piedmont Natural Gas [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	197
Progress Energy [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	$ 1,653	$ 1,798

Debt and Credit Facilities (S94

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt issuances	$ 9,127	$ 2,700
April 2016 Debt Maturing April 2023 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350
Interest rate	2.875%
August 2016 Debt Maturing September 2021 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 750
Interest rate	1.80%
August 2016 Debt Maturing September 2026 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500
Interest rate	2.65%
August 2016 Debt Maturing September 2046 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500
Interest rate	3.75%
June 2016 Debt Maturing March 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 183
Interest rate	1.196%
June 2016 Debt Maturing September 2022 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 150
Interest rate	1.731%
June 2016 Debt Maturing September 2029 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 436
Interest rate	2.538%
June 2016 Debt Maturing March 2033 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	2.858%
June 2016 Debt Maturing September 2036 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 275
Interest rate	3.112%
August 2016 Debt Tranche A Maturing June 2034 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 228
Interest rate	2.747%
August 2016 Debt Tranche B Maturing June 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 105
Interest rate	2.747%
March 2016 Debt Maturing March 2023 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	2.50%
March 2016 Debt Maturing March 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.875%
May 2016 Debt Maturing May 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.75%
Repayments of Debt	$ 325
May 2016 Debt 2 Maturing May 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of Debt	150
June 2016 Debt Maturing June 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	3.70%
September 2016 Debt Maturing October 2046 3.4% [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600
Interest rate	3.40%
September 2016 Debt Maturing October 2046 3.7%[Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450
Interest rate	3.70%
November 2016 Debt Maturing December 2026 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600
Interest rate	2.95%
Repayments of Debt	$ 350
November 2015 Debt Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400
Interest rate		3.75%
Repayments of Debt		$ 300
November 2015 Debt Maturing December 2045 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 600
Interest rate		4.80%
Repayments of Debt		$ 300
March 2015 Debt Maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Interest rate		3.75%
Repayments of Debt		$ 500
August 2015 Debt Maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Interest rate		3.25%
Repayments of Debt		$ 400
August 2015 Debt Maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 700
Interest rate		4.20%
Repayments of Debt		$ 400
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	4,100	1,000
Parent Company [Member] | April 2016 Debt Maturing April 2023 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350
Interest rate	2.875%
Parent Company [Member] | August 2016 Debt Maturing September 2021 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 750
Interest rate	1.80%
Parent Company [Member] | August 2016 Debt Maturing September 2026 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500
Interest rate	2.65%
Parent Company [Member] | August 2016 Debt Maturing September 2046 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500
Interest rate	3.75%
Parent Company [Member] | November 2015 Debt Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400
Interest rate		3.75%
Repayments of Debt		$ 300
Parent Company [Member] | November 2015 Debt Maturing December 2045 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 600
Interest rate		4.80%
Repayments of Debt		$ 300
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,600	500
Duke Energy Carolinas [Member] | March 2016 Debt Maturing March 2023 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	2.50%
Duke Energy Carolinas [Member] | March 2016 Debt Maturing March 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.875%
Duke Energy Carolinas [Member] | November 2016 Debt Maturing December 2026 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600
Interest rate	2.95%
Repayments of Debt	$ 350
Duke Energy Carolinas [Member] | March 2015 Debt Maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Interest rate		3.75%
Repayments of Debt		$ 500
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances	450	1,200
Duke Energy Progress [Member] | September 2016 Debt Maturing October 2046 3.7%[Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450
Interest rate	3.70%
Duke Energy Progress [Member] | March 2015 Debt Maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		0
Duke Energy Progress [Member] | August 2015 Debt Maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Interest rate		3.25%
Repayments of Debt		$ 400
Duke Energy Progress [Member] | August 2015 Debt Maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 700
Interest rate		4.20%
Repayments of Debt		$ 400
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,894
Duke Energy Florida [Member] | June 2016 Debt Maturing March 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 183
Interest rate	1.196%
Duke Energy Florida [Member] | June 2016 Debt Maturing September 2022 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 150
Interest rate	1.731%
Duke Energy Florida [Member] | June 2016 Debt Maturing September 2029 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 436
Interest rate	2.538%
Duke Energy Florida [Member] | June 2016 Debt Maturing March 2033 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	2.858%
Duke Energy Florida [Member] | June 2016 Debt Maturing September 2036 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 275
Interest rate	3.112%
Duke Energy Florida [Member] | September 2016 Debt Maturing October 2046 3.4% [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600
Interest rate	3.40%
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Duke Energy Ohio [Member] | June 2016 Debt Maturing June 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	3.70%
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Duke Energy Indiana [Member] | May 2016 Debt Maturing May 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.75%
Repayments of Debt	$ 325
Duke Energy Indiana [Member] | May 2016 Debt 2 Maturing May 2046 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 150

Debt and Credit Facilities (Ann

Debt and Credit Facilities (Annual Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	$ 2,319	$ 2,026
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	2,319
2,018	3,466
2,019	3,316
2,020	2,112
2,021	3,699
Thereafter	31,090
Total long-term debt, including current maturities	46,002
Other Debt Obligations [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	$ 293
June 2017 Maturity [Member] | Secured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	2.365%
Current maturities of long-term debt	$ 45
June 2017 Maturity 2 [Member] | Secured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	2.26%
Current maturities of long-term debt	$ 34
Purchase Accounting Adjustments [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Purchase accounting adjustments	$ (1,893)
Parent Company [Member] | April 2017 Debt Maturity [Member] | Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	1.226%
Current maturities of long-term debt	$ 400
Parent Company [Member] | August 2017 Debt Maturity [Member] | Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	1.625%
Current maturities of long-term debt	$ 700
Piedmont Natural Gas [Member] | September 2017 Debt Maturity [Member] | Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	8.51%
Current maturities of long-term debt	$ 35
Duke Energy Carolinas [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	116	356
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	116
2,018	1,629
2,019	5
2,020	755
2,021	501
Thereafter	6,597
Total long-term debt, including current maturities	$ 9,603
Duke Energy Carolinas [Member] | February 2017 Debt Maturity [Member] | Tax Exempt Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	3.60%
Current maturities of long-term debt	$ 77
Duke Energy Carolinas [Member] | February 2017 Debt Maturity 2 [Member] | Tax Exempt Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	0.81%
Current maturities of long-term debt	$ 10
Duke Energy Carolinas [Member] | February 2017 Debt Maturity 3 [Member] | Tax Exempt Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	0.79%
Current maturities of long-term debt	$ 25
Progress Energy [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	778	315
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	778
2,018	559
2,019	1,992
2,020	469
2,021	1,473
Thereafter	12,270
Total long-term debt, including current maturities	17,541
Duke Energy Progress [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	452	2
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	452
2,018	0
2,019	902
2,020	152
2,021	602
Thereafter	4,903
Total long-term debt, including current maturities	$ 7,011
Duke Energy Progress [Member] | March 2017 Debt Maturity [Member] | First Mortgage Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	1.146%
Current maturities of long-term debt	$ 250
Duke Energy Progress [Member] | November 2017 Debt Maturity [Member] | First Mortgage Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	1.111%
Current maturities of long-term debt	$ 200
Duke Energy Florida [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	326	13
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	326
2,018	561
2,019	292
2,020	319
2,021	372
Thereafter	4,255
Total long-term debt, including current maturities	$ 6,125
Duke Energy Florida [Member] | September 2017 Debt Maturity [Member] | First Mortgage Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	5.80%
Current maturities of long-term debt	$ 250
Duke Energy Ohio [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	1	106
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	1
2,018	3
2,019	551
2,020	25
2,021	49
Thereafter	1,255
Total long-term debt, including current maturities	1,884
Duke Energy Indiana [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	3	$ 547
Long-term Debt, Fiscal Year Maturity [Abstract]
2,017	3
2,018	3
2,019	63
2,020	653
2,021	70
Thereafter	2,994
Total long-term debt, including current maturities	$ 3,786

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Tax exempt bonds	$ (1,053)	$ (1,053)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	8,350
Commercial Paper	(2,022)
Outstanding letters of credit	(78)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	5,634
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	3,400
Commercial Paper	(977)
Outstanding letters of credit	(69)
Available capacity	2,354
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(355)	(355)
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,100
Commercial Paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	511
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	850
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(48)	(48)
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,000
Commercial Paper	(150)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	598
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	950
Commercial Paper	(84)
Outstanding letters of credit	(1)
Available capacity	865
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(77)	(77)
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	450
Commercial Paper	(31)
Available capacity	419
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(572)	$ (572)
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	600
Commercial Paper	(150)
Tax exempt bonds	(81)
Available capacity	369
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commercial Paper	$ (625)

Guarantees and Indemnificatio97

Guarantees and Indemnifications(Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Liabilities Recorded for Third Party Guarantees [Abstract]
Face value of guarantees	$ 13	$ 21
Surety Bond [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	44
Standby Letters Of Credit [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	485
Unused letters of credit	77
Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	333
Maximum potential of future amounts associated with guarantees with expiration dates	215
Performance Guarantee [Member] | Less Than Wholly Owned Entity [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	11
Indemnification Agreement [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	96
Maximum potential amount of future payments associated with guarantees with no expiration date	7
Spectra Capital [Member] | Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	205
Progress Energy [Member]
Liabilities Recorded for Third Party Guarantees [Abstract]
Face value of guarantees		7
Progress Energy [Member] | Indemnification Agreement [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees	96
Maximum potential amount of future payments associated with guarantees with no expiration date	$ 7
Duke Energy Florida [Member]
Liabilities Recorded for Third Party Guarantees [Abstract]
Face value of guarantees		$ 7

Joint Ownership of Generating98

Joint Ownership of Generating and Transmission Facilities (Table) (Details) $ in Millions	Dec. 31, 2016USD ($)
Duke Energy Carolinas [Member] | Duke Energy Carolinas Catawba Nuclear Station (Units 1 and 2) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	19.25%
Property, plant, and equipment	$ 954
Accumulated depreciation	612
Construction work in progress	12
Duke Energy Ohio [Member] | Duke Energy Ohio Transmission [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	90
Accumulated depreciation	60
Construction work in progress	$ 1
Duke Energy Indiana [Member] | Duke Energy Indiana Gibson Station (Unit 5) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	50.05%
Property, plant, and equipment	$ 333
Accumulated depreciation	157
Construction work in progress	$ 11
Duke Energy Indiana [Member] | Vermillion Generation Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	62.50%
Property, plant, and equipment	$ 154
Accumulated depreciation	111
Duke Energy Indiana [Member] | Duke Energy Indiana Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	4,315
Accumulated depreciation	$ 1,715

Joint Ownership of Generating99

Joint Ownership of Generating and Transmission Facilities (Narrative) (Details) - Duke Energy Florida [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Ownership Percentage of Generating Facility	100.00%
Seminole Electric Cooperative [Member] | Crystal River Nuclear Station (Unit 3) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	1.70%
Florida Municipal Joint Owners [Member] | Crystal River Nuclear Station (Unit 3) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	6.52%
Joint Owner Settlement	$ 55

Asset Retirement Obligations (R

Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 10,611	$ 10,249	$ 8,464
Asset Retirement Obligation, Current	411
Asset Retirement Obligations, Noncurrent	10,200	10,249
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,204
Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,150
Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	257
Duke Energy Carolinas [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,895	3,918	3,428
Asset Retirement Obligation, Current	222
Asset Retirement Obligations, Noncurrent	3,673	3,918
Duke Energy Carolinas [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	1,834
Duke Energy Carolinas [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,032
Duke Energy Carolinas [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	29
Progress Energy [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,475	5,369	4,711
Asset Retirement Obligation, Current	189
Asset Retirement Obligations, Noncurrent	5,286	5,369
Progress Energy [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,172
Progress Energy [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,228
Progress Energy [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	75
Duke Energy Progress [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	4,697	4,567	3,905
Asset Retirement Obligation, Current	189
Asset Retirement Obligations, Noncurrent	4,508	4,567
Duke Energy Progress [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,454
Duke Energy Progress [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,209
Duke Energy Progress [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	34
Duke Energy Florida [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	778	802	806
Asset Retirement Obligations, Noncurrent	778	802
Duke Energy Florida [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	717
Duke Energy Florida [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	19
Duke Energy Florida [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	42
Duke Energy Ohio [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	77	125	27
Asset Retirement Obligations, Noncurrent	77	125
Duke Energy Ohio [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	43
Duke Energy Ohio [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	34
Duke Energy Indiana [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	866	525	$ 32
Asset Retirement Obligations, Noncurrent	866	$ 525
Duke Energy Indiana [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	847
Duke Energy Indiana [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 19

Asset Retirement Obligations (N

Asset Retirement Obligations (NDTF Information)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
NDTF Information [Abstract]
Annual funding requirement	$ 14
Decommissioning costs	8,150
Legally restricted NDTF investments, fair value	5,099	$ 4,670
Duke Energy Carolinas [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	2,882	2,686
Duke Energy Carolinas [Member] | 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning costs	3,420
Duke Energy Progress [Member]
NDTF Information [Abstract]
Legally restricted NDTF investments, fair value	2,217	$ 1,984
Duke Energy Progress [Member] | 2014 Cost Study [Member]
NDTF Information [Abstract]
Annual funding requirement	14
Decommissioning costs	3,550
Duke Energy Florida [Member] | 2013 Cost Study [Member]
NDTF Information [Abstract]
Decommissioning costs	$ 1,180

Asset Retirement Obligations102

Asset Retirement Obligations (Nuclear Operating Licenses)(Details)	12 Months Ended
	Dec. 31, 2016
Duke Energy Carolinas [Member] | Catawba Units 1 and 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,043
Duke Energy Carolinas [Member] | McGuire Unit 1 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,041
Duke Energy Carolinas [Member] | McGuire Unit 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,043
Duke Energy Carolinas [Member] | Oconee Units 1 and 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,033
Duke Energy Carolinas [Member] | Oconee Unit 3 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,034
Duke Energy Progress [Member] | Brunswick Unit 1 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,036
Duke Energy Progress [Member] | Brunswick Unit 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,034
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,046
Duke Energy Progress [Member] | Robinson Nuclear Station [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2,030

Asset Retirement Obligations103

Asset Retirement Obligations (Rollforward)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Asset Retirement Obligation [Line Items]
Balance as of January 1	$ 10,249	$ 8,464
Acquisitions	22	226
Accretion expense	400	380
Liabilities settled	(613)	(422)
Liabilities incurred in the current year	51	1,016
Revisions in estimates of cash flows	502	585
Balance as of December 31	10,611	10,249
Duke Energy Carolinas [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	3,918	3,428
Accretion expense	187	165
Liabilities settled	(287)	(200)
Liabilities incurred in the current year		178
Revisions in estimates of cash flows	77	347
Balance as of December 31	3,895	3,918
Progress Energy [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	5,369	4,711
Acquisitions	2	226
Accretion expense	230	203
Liabilities settled	(272)	(195)
Liabilities incurred in the current year	3	282
Revisions in estimates of cash flows	143	142
Balance as of December 31	5,475	5,369
Duke Energy Progress [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	4,567	3,905
Acquisitions		204
Accretion expense	194	169
Liabilities settled	(212)	(125)
Liabilities incurred in the current year	3	282
Revisions in estimates of cash flows	145	132
Balance as of December 31	4,697	4,567
Duke Energy Florida [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	802	806
Acquisitions	2	23
Accretion expense	35	34
Liabilities settled	(60)	(70)
Revisions in estimates of cash flows	(1)	9
Balance as of December 31	778	802
Duke Energy Ohio [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	125	27
Accretion expense	5	4
Liabilities settled	(5)	(4)
Liabilities incurred in the current year		116
Revisions in estimates of cash flows	(48)	(18)
Balance as of December 31	77	125
Duke Energy Indiana [Member]
Asset Retirement Obligation [Line Items]
Balance as of January 1	525	32
Accretion expense	24	15
Liabilities settled	(49)	(23)
Liabilities incurred in the current year	29	418
Revisions in estimates of cash flows	337	83
Balance as of December 31	$ 866	$ 525

Property, Plant and Equipmen104

Property, Plant and Equipment (Schedule Of Property, Plant and Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	$ 1,501	$ 1,391
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	4,184	4,008
Nuclear fuel	3,572	3,194
Equipment	1,941	1,736
Construction in process	6,186	4,485
Total property, plant and equipment	121,397	109,967
Total accumulated depreciation	(39,406)	(36,736)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	82,520	73,779
Capitalized leases	1,355	1,465
Accumulated amortization on capitalized leases	50	57
Capitalized Interest Costs [Abstract]
Capitalized interest	100	98	$ 75
Operating Leases [Abstract]
Accumulated depreciation and amortization	$ 39,406	$ 36,736
Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Equipment, estimated useful life, years	3 years	3 years
Other, estimated useful life, in years	5 years	5 years
Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Equipment, estimated useful life, years	38 years	38 years
Other, estimated useful life, in years	40 years	60 years
Nuclear Fuel [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	$ (1,922)	$ (1,621)
Operating Leases [Abstract]
Accumulated depreciation and amortization	1,922	1,621
Variable Interest Entity, Primary Beneficiary [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total property, plant and equipment	2,591	2,033
Total accumulated depreciation	(411)	(327)
Operating Leases [Abstract]
Accumulated depreciation and amortization	411	327
Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(37,831)	(35,367)
Operating Leases [Abstract]
Accumulated depreciation and amortization	37,831	35,367
Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 89,864	$ 87,593
Regulated Operation [Member] | Electric [Member] | Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	8 years	8 years
Regulated Operation [Member] | Electric [Member] | Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	100 years	100 years
Regulated Operation [Member] | Natural Gas [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 7,738	$ 2,322
Regulated Operation [Member] | Natural Gas [Member] | Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	12 years	12 years
Regulated Operation [Member] | Natural Gas [Member] | Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	67 years	67 years
Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	$ 1,692	$ 1,480
Regulated Operation [Member] | Other Buildings And Improvements [Member] | Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	15 years	15 years
Regulated Operation [Member] | Other Buildings And Improvements [Member] | Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	100 years	100 years
Nonregulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	$ (1,575)	$ (1,369)
Operating Leases [Abstract]
Accumulated depreciation and amortization	1,575	1,369
Nonregulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	$ 4,298	$ 3,348
Nonregulated Operation [Member] | Electric [Member] | Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	5 years	1 year
Nonregulated Operation [Member] | Electric [Member] | Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution, estimated useful life, in years	30 years	30 years
Nonregulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	$ 421	$ 410
Nonregulated Operation [Member] | Other Buildings And Improvements [Member] | Minimum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	25 years	25 years
Nonregulated Operation [Member] | Other Buildings And Improvements [Member] | Maximum [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Other, estimated useful life, in years	35 years	35 years
Duke Energy Carolinas [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	$ 432	$ 407
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	904	836
Nuclear fuel	2,092	1,827
Equipment	358	368
Construction in process	2,324	1,860
Total property, plant and equipment	41,127	39,398
Total accumulated depreciation	(14,365)	(13,521)
Net property, plant and equipment	26,762	25,877
Capitalized leases	40	40
Accumulated amortization on capitalized leases	9	11
Capitalized Interest Costs [Abstract]
Capitalized interest	38	38	38
Operating Leases [Abstract]
Accumulated depreciation and amortization	14,365	13,521
Duke Energy Carolinas [Member] | Nuclear Fuel [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(1,192)	(976)
Operating Leases [Abstract]
Accumulated depreciation and amortization	1,192	976
Duke Energy Carolinas [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(14,365)	(13,521)
Operating Leases [Abstract]
Accumulated depreciation and amortization	14,365	13,521
Duke Energy Carolinas [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	34,515	33,623
Duke Energy Carolinas [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	502	477
Progress Energy [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	735	719
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	1,206	1,180
Nuclear fuel	1,480	1,367
Equipment	505	530
Construction in process	2,708	1,827
Total property, plant and equipment	44,864	42,666
Total accumulated depreciation	(15,212)	(14,867)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	30,181	28,347
Capitalized leases	288	302
Accumulated amortization on capitalized leases	99	85
Capitalized Interest Costs [Abstract]
Capitalized interest	31	24	11
Operating Leases [Abstract]
Accumulated depreciation and amortization	15,212	14,867
Progress Energy [Member] | Nuclear Fuel [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(730)	(645)
Operating Leases [Abstract]
Accumulated depreciation and amortization	730	645
Progress Energy [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(15,212)	(14,867)
Operating Leases [Abstract]
Accumulated depreciation and amortization	15,212	14,867
Progress Energy [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	37,596	36,422
Progress Energy [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	634	621
Duke Energy Progress [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	393	392
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	863	856
Nuclear fuel	1,480	1,367
Equipment	378	398
Construction in process	1,329	1,118
Total property, plant and equipment	28,419	27,313
Total accumulated depreciation	(10,561)	(10,141)
Generation facilities to be retired, net	529	548
Net property, plant and equipment	18,387	17,720
Capitalized leases	142	144
Accumulated amortization on capitalized leases	9	7
Capitalized Interest Costs [Abstract]
Capitalized interest	17	20	10
Operating Leases [Abstract]
Accumulated depreciation and amortization	10,561	10,141
Duke Energy Progress [Member] | Nuclear Fuel [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(730)	(645)
Operating Leases [Abstract]
Accumulated depreciation and amortization	730	645
Duke Energy Progress [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(10,561)	(10,141)
Operating Leases [Abstract]
Accumulated depreciation and amortization	10,561	10,141
Duke Energy Progress [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	23,683	22,888
Duke Energy Progress [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	293	294
Duke Energy Florida [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	342	327
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	332	319
Equipment	127	132
Construction in process	1,379	709
Total property, plant and equipment	16,434	15,343
Total accumulated depreciation	(4,644)	(4,720)
Net property, plant and equipment	11,790	10,623
Capitalized leases	146	158
Accumulated amortization on capitalized leases	90	78
Capitalized Interest Costs [Abstract]
Capitalized interest	14	4	1
Operating Leases [Abstract]
Accumulated depreciation and amortization	4,644	4,720
Duke Energy Florida [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(4,644)	(4,720)
Operating Leases [Abstract]
Accumulated depreciation and amortization	4,644	4,720
Duke Energy Florida [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	13,913	13,534
Duke Energy Florida [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	341	322
Duke Energy Ohio [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	150	118
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	172	153
Equipment	338	344
Construction in process	206	180
Total property, plant and equipment	8,126	7,750
Total accumulated depreciation	(2,579)	(2,507)
Net property, plant and equipment	5,547	5,243
Capitalized leases	81	96
Accumulated amortization on capitalized leases	19	27
Capitalized Interest Costs [Abstract]
Capitalized interest	8	10	10
Operating Leases [Abstract]
Accumulated depreciation and amortization	2,579	2,507
Duke Energy Ohio [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(2,579)	(2,507)
Operating Leases [Abstract]
Accumulated depreciation and amortization	2,579	2,507
Duke Energy Ohio [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	4,593	4,429
Duke Energy Ohio [Member] | Regulated Operation [Member] | Natural Gas [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	2,456	2,322
Duke Energy Ohio [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	211	204
Duke Energy Indiana [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Land	106	108
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	226	215
Equipment	156	173
Construction in process	396	214
Total property, plant and equipment	14,241	14,007
Total accumulated depreciation	(4,317)	(4,484)
Net property, plant and equipment	9,924	9,523
Capitalized leases	35	39
Accumulated amortization on capitalized leases	8	7
Capitalized Interest Costs [Abstract]
Capitalized interest	7	6	6
Operating Leases [Abstract]
Accumulated depreciation and amortization	4,317	4,484
Duke Energy Indiana [Member] | Regulated Operation [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(4,317)	(4,484)
Operating Leases [Abstract]
Accumulated depreciation and amortization	4,317	4,484
Duke Energy Indiana [Member] | Regulated Operation [Member] | Electric [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Plant - transmission and distribution	13,160	13,118
Duke Energy Indiana [Member] | Regulated Operation [Member] | Other Buildings And Improvements [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	197	179
Commercial Renewables [Member] | Assets Leased to Others [Member]
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Total accumulated depreciation	(347)
Operating Leases [Abstract]
Contingent lease payments	216	$ 172	$ 164
Renewable energy projects	3,127
Accumulated depreciation and amortization	$ 347

Goodwill and Intangible Asse105

Goodwill and Intangible Assets Goodwill and Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 19,425	$ 16,072
Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	17,379	15,656
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	1,924	294
Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill	920	920
Goodwill, Impaired, Accumulated Impairment Loss	216	216
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	596	596
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill	$ 324	$ 324

Goodwill and Intangible Asse106

Goodwill and Intangible Assets (Goodwill By Reportable Operating Segment) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	$ 16,072
Goodwill, Acquired During Period	3,353
Goodwill, balance at end of period	19,425
Electric Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	15,656
Goodwill, Acquired During Period	1,723
Goodwill, balance at end of period	17,379
Gas Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	294
Goodwill, Acquired During Period	1,630
Goodwill, balance at end of period	1,924
Commercial Renewables [Member]
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	122
Goodwill, balance at end of period	$ 122

Goodwill and Intangible Asse107

Goodwill and Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	$ 271	$ 277
Accumulated amortization	(45)	(35)
Total intangible assets, net	226	242
Amortization expense	6	5	$ 6
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2,017	5
2,018	5
2,019	5
2,020	5
2,021	5
Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	19	20
Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	125	116
Gas Coal And Power Contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	(17)	(16)
Renewable Operating and Development Projects [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	97	115
Accumulated amortization	(23)	(18)
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	6	2
Accumulated amortization	(5)	(1)
Duke Energy Carolinas [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	37	31
Total intangible assets, net	37	31
Duke Energy Carolinas [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	1	1
Duke Energy Carolinas [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	36	30
Progress Energy [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	90	86
Total intangible assets, net	90	86
Progress Energy [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	6	6
Progress Energy [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	84	80
Duke Energy Progress [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	86	82
Total intangible assets, net	86	82
Duke Energy Progress [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	2
Duke Energy Progress [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	84	80
Duke Energy Florida [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	4	4
Total intangible assets, net	4	4
Duke Energy Florida [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	4	4
Duke Energy Ohio [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	4	5
Total intangible assets, net	4	5
Amortization expense			2
Duke Energy Ohio [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0
Duke Energy Ohio [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	4	5
Duke Energy Ohio [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0
Accumulated amortization	0
Duke Energy Indiana [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	37	38
Accumulated amortization	(17)	(16)
Total intangible assets, net	20	22
Amortization expense	1	1	$ 1
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2,017	2
2,018	2
2,019	2
2,020	2
2,021	2
Duke Energy Indiana [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	13	14
Duke Energy Indiana [Member] | Gas Coal And Power Contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	$ (17)	$ (16)

Investments in Unconsolidate108

Investments in Unconsolidated Affiliates (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2017
Investments In Unconsolidated Affiliates [Line Items]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 24
Distributions from equity investments	31	$ 104	$ 154
Asset Impairment Charges	$ 18	$ 106	$ 81
Electric Utilities and Infrastructure [Member] | Duke American Transmission Co. [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage	50.00%
Electric Utilities and Infrastructure [Member] | Pioneer Transmission [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage	50.00%
Commercial Renewables [Member]
Investments In Unconsolidated Affiliates [Line Items]
Asset Impairment Charges	$ 71
Commercial Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Investments In Unconsolidated Affiliates [Line Items]
Asset Impairment Charges	$ 71
Commercial Renewables [Member] | Sweetwater IV-V [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage	47.00%
Commercial Renewables [Member] | DS Cornerstone [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage	50.00%
Other [Member] | National Methanol Company [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage	25.00%
Other [Member] | National Methanol Company [Member] | Scenario, Forecast [Member]
Investments In Unconsolidated Affiliates [Line Items]
Equity method investment, ownership percentage				17.50%
Board representation and voting rights, ownership percentage				25.00%

Investments in Unconsolidate109

Investments in Unconsolidated Affiliates (Investments in Equity Method Unconsolidated Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments In Unconsolidated Affiliates [Line Items]
Investments in unconsolidated affiliates	$ 925	$ 499
Equity in earnings (losses) of unconsolidated affiliates	(15)	69	$ 130
Electric Utilities and Infrastructure [Member]
Investments In Unconsolidated Affiliates [Line Items]
Investments in unconsolidated affiliates	93	57
Equity in earnings (losses) of unconsolidated affiliates	5	(2)	(1)
Gas Utilities and Infrastructure [Member]
Investments In Unconsolidated Affiliates [Line Items]
Investments in unconsolidated affiliates	566	113
Equity in earnings (losses) of unconsolidated affiliates	19	1	0
Commercial Renewables [Member]
Investments In Unconsolidated Affiliates [Line Items]
Investments in unconsolidated affiliates	185	265
Equity in earnings (losses) of unconsolidated affiliates	(82)	(6)	8
Other [Member]
Investments In Unconsolidated Affiliates [Line Items]
Investments in unconsolidated affiliates	81	64
Equity in earnings (losses) of unconsolidated affiliates	$ 43	$ 76	$ 123

Investments in Unconsolidate110

Investments in Unconsolidated Affiliates (Gas Utilities and Infrastructure Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 925	$ 499
Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 566	113
Atlantic Coast Pipeline [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	47.00%
Equity Method Investments	$ 265	52
Sabal Trail Transmission Pipeline [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	7.50%
Equity Method Investments	$ 140	$ 61
Constitution Pipeline [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	24.00%
Equity Method Investments	$ 82
Cardinal Pipeline Company, LLC [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	21.49%
Equity Method Investments	$ 16
Pine Needle LNG Company, LLC [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	45.00%
Equity Method Investments	$ 16
Hardy Storage Company, LLC [Member] | Gas Utilities and Infrastructure [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Equity Method Investments	$ 47

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 831	$ 914	$ 851
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	22	24	21
Duke Energy Carolinas [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	38	51	133
Related party transaction, expenses from transactions with related party	156	183	198
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	710	712	732
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	35	38	33
Progress Energy [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	156	183	198
Related party transaction, expenses from transactions with related party	38	51	133
Progress Energy [Member] | Intercompany Natural Gas Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	397	403	386
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	14	16	17
Duke Energy Progress [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	156	183	198
Related party transaction, expenses from transactions with related party	38	51	133
Duke Energy Progress [Member] | Intercompany Natural Gas Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19
Duke Energy Florida [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	313	309	346
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	21	22	16
Duke Energy Ohio [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	356	342	316
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6	13
Duke Energy Indiana [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	366	349	384
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 8	$ 9	$ 11

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - Duke Energy Ohio [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Apr. 01, 2015
Related Party Transaction [Line Items]
Intercompany loan payable	$ 16	$ 103
Decam [Member]
Related Party Transaction [Line Items]
Intercompany loan payable			$ 294

Related Party Transactions Inte

Related Party Transactions Intercompany Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Duke Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	$ 163	$ 107
Intercompany income tax payable	247	229
Duke Energy Carolinas [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	1	122
Progress Energy [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	106	375
Intercompany income tax payable	348	311
Progress Energy [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		120
Intercompany income tax payable	37
Duke Energy Progress [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	5	16
Intercompany income tax payable	227	190
Duke Energy Progress [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		104
Intercompany income tax payable	90
Duke Energy Florida [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	5	84
Intercompany income tax payable	125	116
Duke Energy Florida [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	37
Intercompany income tax payable		96
Duke Energy Ohio [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	129	84
Intercompany income tax payable	63	53
Duke Energy Ohio [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		54
Intercompany income tax payable	1
Duke Energy Indiana [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	114	71
Intercompany income tax payable	74	83
Duke Energy Indiana [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax payable	$ 3	$ 47

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Bcf in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)GWhBcf	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)GWhBcf
Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 1,677		$ 2,324
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	750		497
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 927		$ 1,827
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | GWh	147		70
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	890		398
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 750		$ 497
Piedmont Natural Gas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(190)
Piedmont Natural Gas [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ (190)
Notional Amount		$ 1,400
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	529
Duke Energy Carolinas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 400		400
Duke Energy Carolinas [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 400		$ 400
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	91		66
Progress Energy [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 500		$ 500
Progress Energy [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 500		$ 500
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	269		332
Duke Energy Progress [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Progress [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	118		117
Duke Energy Florida [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Florida [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	151		215
Duke Energy Ohio [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 27		$ 27
Duke Energy Ohio [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 27		$ 27
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | GWh			34
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | GWh	147		36
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	1
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 300
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | 4YearInterestRateContract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	81
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | 18YearInterestRateContract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 219

Derivatives and Hedging (Locati

Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 162	$ 25
Location and fair value amounts of derivatives (Liability)	252	397
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	140	16
Location and fair value amounts of derivatives (Liability)	209	356
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	9
Location and fair value amounts of derivatives (Liability)	43	41
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	9
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	19	3
Location and fair value amounts of derivatives (Liability)	8	13
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	108	12
Location and fair value amounts of derivatives (Liability)	43	256
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	32	4
Location and fair value amounts of derivatives (Liability)	166	100
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Location and fair value amounts of derivatives (Liability)	1	4
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	15
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	33
Location and fair value amounts of derivatives (Liability)	16	45
Duke Energy Carolinas [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	33
Location and fair value amounts of derivatives (Liability)	1	40
Duke Energy Carolinas [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	15	5
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	23
Location and fair value amounts of derivatives (Liability)		32
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Location and fair value amounts of derivatives (Liability)	1	8
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	15	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	85	11
Location and fair value amounts of derivatives (Liability)	25	322
Progress Energy [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	82	5
Location and fair value amounts of derivatives (Liability)	19	314
Progress Energy [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Location and fair value amounts of derivatives (Liability)	6	8
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	61	1
Location and fair value amounts of derivatives (Liability)	12	222
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	21	4
Location and fair value amounts of derivatives (Liability)	7	92
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Location and fair value amounts of derivatives (Liability)		3
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	46	2
Location and fair value amounts of derivatives (Liability)	7	98
Duke Energy Progress [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	45
Location and fair value amounts of derivatives (Liability)	1	93
Duke Energy Progress [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	35
Location and fair value amounts of derivatives (Liability)		77
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Location and fair value amounts of derivatives (Liability)	1	16
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	39	7
Location and fair value amounts of derivatives (Liability)	12	216
Duke Energy Florida [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	37	5
Location and fair value amounts of derivatives (Liability)	12	216
Duke Energy Florida [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	26	1
Location and fair value amounts of derivatives (Liability)	12	145
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	4
Location and fair value amounts of derivatives (Liability)		71
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	2
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	3
Location and fair value amounts of derivatives (Liability)	6	7
Duke Energy Ohio [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	3
Duke Energy Ohio [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	7
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	3
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	6
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	7
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Indiana [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	7
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	$ 7
Location and fair value amounts of derivatives (Liability)	$ 2

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 162	$ 25
Net amounts presented on Balance Sheets	162	25
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	252	397
Net amounts presented on Balance Sheets	252	397
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	111	18
Gross amounts offset	(11)	(3)
Net amounts presented on Balance Sheets	100	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	51	7
Gross amounts offset	(2)	(4)
Net amounts presented on Balance Sheets	49	3
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	52	269
Gross amounts offset	(11)	(22)
Net amounts presented on Balance Sheets	41	247
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	200	128
Gross amounts offset	(2)	(16)
Net amounts presented on Balance Sheets	198	112
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	33
Net amounts presented on Balance Sheets	33
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	16	45
Net amounts presented on Balance Sheets	16	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	23
Net amounts presented on Balance Sheets	23
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	9
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		32
Net amounts presented on Balance Sheets		32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	16	13
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	15	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	85	11
Net amounts presented on Balance Sheets	85	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	25	322
Net amounts presented on Balance Sheets	25	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	64	7
Gross amounts offset	(11)	(2)
Net amounts presented on Balance Sheets	53	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	21	4
Gross amounts offset	(1)	(4)
Net amounts presented on Balance Sheets	20
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	225
Gross amounts offset	(11)	(21)
Net amounts presented on Balance Sheets	1	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	13	97
Gross amounts offset	(1)	(15)
Net amounts presented on Balance Sheets	12	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	46	2
Net amounts presented on Balance Sheets	46	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	98
Net amounts presented on Balance Sheets	7	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	36	2
Net amounts presented on Balance Sheets	36	2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	9
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		77
Gross amounts offset		(1)
Net amounts presented on Balance Sheets		76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	21
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	6	21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	39	7
Net amounts presented on Balance Sheets	39	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	216
Net amounts presented on Balance Sheets	12	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	28	3
Gross amounts offset	(11)	(2)
Net amounts presented on Balance Sheets	17	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	4
Gross amounts offset		(4)
Net amounts presented on Balance Sheets	11
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	145
Gross amounts offset	(11)	(20)
Net amounts presented on Balance Sheets	1	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		71
Gross amounts offset		(15)
Net amounts presented on Balance Sheets		56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	3
Net amounts presented on Balance Sheets	5	3
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	7
Net amounts presented on Balance Sheets	6	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	3
Net amounts presented on Balance Sheets	4	3
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1
Net amounts presented on Balance Sheets	1
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts presented on Balance Sheets	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	6
Net amounts presented on Balance Sheets	5	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Net amounts presented on Balance Sheets	16	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	2
Net amounts presented on Balance Sheets	2
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Net amounts presented on Balance Sheets	16	$ 7
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	2
Net amounts presented on Balance Sheets	$ 2

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	$ 34	$ 334
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	34	304
Information Regarding Cash Collateral Under Master Netting Arrangements
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		30
Duke Energy Carolinas [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	16	45
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	16	45
Progress Energy [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	18	290
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	18	260
Information Regarding Cash Collateral Under Master Netting Arrangements
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		30
Duke Energy Progress [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	6	93
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	6	93
Duke Energy Florida [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	12	194
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 12	164
Information Regarding Cash Collateral Under Master Netting Arrangements
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		$ 30

Investments in Debt and Equi118

Investments in Debt and Equity Securities (Narrative) (Details) $ in Millions	Dec. 31, 2016USD ($)
Investments, Debt and Equity Securities [Abstract]
Trading Securities	$ 5

Investments in Debt and Equi119

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 2,156	$ 1,882
Gross Unrealized Holding Losses	88	83
Estimated Fair Value	6,554	6,214
NDTF [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2,115	1,846
Gross Unrealized Holding Losses	83	76
Estimated Fair Value	6,184	5,817
NDTF [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	111	179
NDTF [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2,092	1,823
Gross Unrealized Holding Losses	54	58
Estimated Fair Value	4,106	3,590
NDTF [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10	7
Gross Unrealized Holding Losses	8	8
Estimated Fair Value	528	432
NDTF [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	5
Gross Unrealized Holding Losses	10	1
Estimated Fair Value	331	185
NDTF [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10	11
Gross Unrealized Holding Losses	8	5
Estimated Fair Value	984	1,254
NDTF [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	3	4
Estimated Fair Value	124	177
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	41	36
Gross Unrealized Holding Losses	5	7
Estimated Fair Value	370	397
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	25	29
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	38	32
Gross Unrealized Holding Losses		1
Estimated Fair Value	104	95
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	1	3
Estimated Fair Value	66	92
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	82	74
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1
Estimated Fair Value	51	45
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	42	62
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,165	1,028
Gross Unrealized Holding Losses	45	40
Estimated Fair Value	3,261	3,041
Duke Energy Carolinas [Member] | NDTF [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,165	1,028
Gross Unrealized Holding Losses	44	39
Estimated Fair Value	3,258	3,038
Duke Energy Carolinas [Member] | NDTF [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	18	34
Duke Energy Carolinas [Member] | NDTF [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,157	1,021
Gross Unrealized Holding Losses	28	27
Estimated Fair Value	2,245	2,094
Duke Energy Carolinas [Member] | NDTF [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	3
Gross Unrealized Holding Losses	6	5
Estimated Fair Value	354	292
Duke Energy Carolinas [Member] | NDTF [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	2
Estimated Fair Value	67	33
Duke Energy Carolinas [Member] | NDTF [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Gross Unrealized Holding Losses	5	3
Estimated Fair Value	458	438
Duke Energy Carolinas [Member] | NDTF [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	3	4
Estimated Fair Value	116	147
Duke Energy Carolinas [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	952	821
Gross Unrealized Holding Losses	39	37
Estimated Fair Value	2,991	2,842
Progress Energy [Member] | NDTF [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	950	818
Gross Unrealized Holding Losses	39	37
Estimated Fair Value	2,926	2,779
Progress Energy [Member] | NDTF [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	93	145
Progress Energy [Member] | NDTF [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	935	802
Gross Unrealized Holding Losses	26	31
Estimated Fair Value	1,861	1,496
Progress Energy [Member] | NDTF [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	4
Gross Unrealized Holding Losses	2	3
Estimated Fair Value	174	140
Progress Energy [Member] | NDTF [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	4
Gross Unrealized Holding Losses	8	1
Estimated Fair Value	264	152
Progress Energy [Member] | NDTF [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8	8
Gross Unrealized Holding Losses	3	2
Estimated Fair Value	526	816
Progress Energy [Member] | NDTF [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	8	30
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Estimated Fair Value	65	63
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	21	18
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Estimated Fair Value	44	45
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	715	609
Gross Unrealized Holding Losses	32	30
Estimated Fair Value	2,214	2,039
Duke Energy Progress [Member] | NDTF [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	715	609
Gross Unrealized Holding Losses	32	30
Estimated Fair Value	2,213	2,038
Duke Energy Progress [Member] | NDTF [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	45	110
Duke Energy Progress [Member] | NDTF [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	704	596
Gross Unrealized Holding Losses	21	25
Estimated Fair Value	1,505	1,178
Duke Energy Progress [Member] | NDTF [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	120	96
Duke Energy Progress [Member] | NDTF [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	4
Gross Unrealized Holding Losses	8	1
Estimated Fair Value	263	150
Duke Energy Progress [Member] | NDTF [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	6
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	275	486
Duke Energy Progress [Member] | NDTF [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	5	18
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	237	212
Gross Unrealized Holding Losses	7	7
Estimated Fair Value	761	792
Duke Energy Florida [Member] | NDTF [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	235	209
Gross Unrealized Holding Losses	7	7
Estimated Fair Value	713	741
Duke Energy Florida [Member] | NDTF [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	48	35
Duke Energy Florida [Member] | NDTF [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	231	206
Gross Unrealized Holding Losses	5	6
Estimated Fair Value	356	318
Duke Energy Florida [Member] | NDTF [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	54	44
Duke Energy Florida [Member] | NDTF [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	2
Duke Energy Florida [Member] | NDTF [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	1
Estimated Fair Value	251	330
Duke Energy Florida [Member] | NDTF [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3	12
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Estimated Fair Value	48	51
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	4	6
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	3
Estimated Fair Value	44	45
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	33	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	110	101
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	33	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	110	101
Duke Energy Indiana [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value		2
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	33	27
Estimated Fair Value	79	71
Duke Energy Indiana [Member] | Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	2
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	28	$ 26
Duke Energy Indiana [Member] | Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 1

Investments in Debt and Equi120

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 94
Due after one through five years	653
Due after five through ten years	515
Due after ten years	946
Total	2,208
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	3
Due after one through five years	230
Due after five through ten years	260
Due after ten years	505
Total	998
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	84
Due after one through five years	347
Due after five through ten years	187
Due after ten years	398
Total	1,016
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	28
Due after one through five years	190
Due after five through ten years	142
Due after ten years	303
Total	663
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	56
Due after one through five years	157
Due after five through ten years	45
Due after ten years	95
Total	353
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	3
Due after one through five years	13
Due after five through ten years	9
Due after ten years	6
Total	$ 31

Investments in Debt and Equi121

Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$ 246	$ 193	$ 271
Realized losses	187	98	105
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	157	158	109
Realized losses	121	83	93
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	84	33	157
Realized losses	64	13	11
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	71	26	19
Realized losses	55	11	5
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	13	7	138
Realized losses	$ 9	$ 2	$ 5

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$ 162	$ 25
Assets, fair value disclosure	6,716	6,239
Derivative liabilities	(252)	(397)
Net assets, fair value	6,464	5,842
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5
Assets, fair value disclosure	4,845	4,260
Derivative liabilities	(2)
Net assets, fair value	4,843	4,260
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	136	15
Assets, fair value disclosure	1,768	1,792
Derivative liabilities	(63)	(397)
Net assets, fair value	1,705	1,395
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	21	10
Assets, fair value disclosure	26	15
Derivative liabilities	(187)
Net assets, fair value	(161)	15
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	77	172
Equity Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	77	172
Investments	4,106	3,590
Equity Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	4,029	3,418
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	104	95
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	104	95
Debt Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,078	2,227
Debt Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	632	672
Debt Securities [Member] | NDTF [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,446	1,555
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	266	302
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	75	75
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	186	222
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	5	5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	33
Assets, fair value disclosure	3,294	3,041
Derivative liabilities	(16)	(45)
Net assets, fair value	3,278	2,996
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Assets, fair value disclosure	2,346	2,168
Derivative liabilities	0
Net assets, fair value	2,346	2,168
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	33
Assets, fair value disclosure	868	698
Derivative liabilities	(16)	(45)
Net assets, fair value	852	653
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	3	3
Net assets, fair value	3	3
Duke Energy Carolinas [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	77	172
Duke Energy Carolinas [Member] | Equity Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	77	172
Investments	2,245	2,094
Duke Energy Carolinas [Member] | Equity Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,168	1,922
Duke Energy Carolinas [Member] | Debt Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,013	944
Duke Energy Carolinas [Member] | Debt Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	178	246
Duke Energy Carolinas [Member] | Debt Securities [Member] | NDTF [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	835	698
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	3
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	3
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	85	11
Assets, fair value disclosure	3,076	2,853
Derivative liabilities	(25)	(322)
Net assets, fair value	3,051	2,531
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Assets, fair value disclosure	2,336	1,940
Derivative liabilities	0
Net assets, fair value	2,336	1,940
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	85	11
Assets, fair value disclosure	740	913
Derivative liabilities	(25)	(322)
Net assets, fair value	715	591
Progress Energy [Member] | Equity Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,861	1,496
Progress Energy [Member] | Equity Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,861	1,496
Progress Energy [Member] | Debt Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,065	1,283
Progress Energy [Member] | Debt Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	454	426
Progress Energy [Member] | Debt Securities [Member] | NDTF [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	611	857
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	65	63
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	21	18
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	44	45
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	46	2
Assets, fair value disclosure	2,260	2,041
Derivative liabilities	(7)	(98)
Net assets, fair value	2,253	1,943
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Assets, fair value disclosure	1,713	1,320
Derivative liabilities	0
Net assets, fair value	1,713	1,320
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	46	2
Assets, fair value disclosure	547	721
Derivative liabilities	(7)	(98)
Net assets, fair value	540	623
Duke Energy Progress [Member] | Equity Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,505	1,178
Duke Energy Progress [Member] | Equity Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,505	1,178
Duke Energy Progress [Member] | Debt Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	708	860
Duke Energy Progress [Member] | Debt Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	207	141
Duke Energy Progress [Member] | Debt Securities [Member] | NDTF [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	501	719
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	39	7
Assets, fair value disclosure	800	799
Derivative liabilities	(12)	(216)
Net assets, fair value	788	583
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	607	609
Net assets, fair value	607	609
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	39	7
Assets, fair value disclosure	193	190
Derivative liabilities	(12)	(216)
Net assets, fair value	181	(26)
Duke Energy Florida [Member] | Equity Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	356	318
Duke Energy Florida [Member] | Equity Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	356	318
Duke Energy Florida [Member] | Debt Securities [Member] | NDTF [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	357	423
Duke Energy Florida [Member] | Debt Securities [Member] | NDTF [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	247	285
Duke Energy Florida [Member] | Debt Securities [Member] | NDTF [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	110	138
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	48	51
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	4	6
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	44	45
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	3
Derivative liabilities	(6)	(7)
Net assets, fair value	(1)	(4)
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(6)	(7)
Net assets, fair value	(6)	(7)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	3
Net assets, fair value	5	3
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	7
Assets, fair value disclosure	126
Derivative liabilities	(2)
Net assets, fair value	124	108
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Assets, fair value disclosure	79
Derivative liabilities	2
Net assets, fair value	77	73
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	31
Net assets, fair value	31	28
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	7
Assets, fair value disclosure	16
Net assets, fair value	16	7
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	79	71
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	79	71
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	31	30
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		2
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 31	$ 28

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Investments
Beginning balance	$ 15	$ 4
Total pretax gains (losses) included in earnings		21
Purchases	33	24
Sales		(1)
Settlements	(28)	(37)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	6	4
Ending balance	(161)	15
Derivatives (net)
Beginning balance	10	(1)
Total pretax gains (losses) included in earnings		21
Purchases	33	24
Sales		(1)
Settlements	(28)	(37)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	6	4
Ending balance	(166)	10
Investments [Member]
Investments
Beginning balance	5	5
Ending balance	5	5
Duke Energy Ohio [Member]
Derivatives (net)
Beginning balance	3	(18)
Total pretax gains (losses) included in earnings		21
Purchases	5	5
Settlements	(5)	(5)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	2
Ending balance	5	3
Duke Energy Indiana [Member]
Derivatives (net)
Beginning balance	7	14
Purchases	29	19
Settlements	(24)	(30)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	4	4
Ending balance	16	$ 7
Piedmont Natural Gas [Member]
Investments
Purchases	(187)
Derivatives (net)
Purchases	$ (187)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)$ / MWh	Dec. 31, 2015USD ($)$ / MWh	Dec. 31, 2014USD ($)
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ (166)	$ 10	$ (1)
Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 21	$ 10
Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	(0.83)	(0.74)
Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	9.32	7.29
Energy Related Derivative [Member] | Natural Gas, derivative liability [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ (187)
Energy Related Derivative [Member] | Natural Gas, derivative liability [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	2.31
Energy Related Derivative [Member] | Natural Gas, derivative liability [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	4.18
Duke Energy Ohio [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 5	$ 3	(18)
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 5	$ 3
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	0.77	0.67
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	3.52	2.53
Duke Energy Indiana [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 16	$ 7	$ 14
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 16	$ 7
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	(0.83)	(0.74)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	9.32	7.29

Fair Value Measurements (Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 47,895	$ 38,868
Long-term debt, fair value	49,161	41,767
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	9,603	8,367
Long-term debt, fair value	10,494	9,156
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	17,541	14,464
Long-term debt, fair value	19,107	15,856
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	7,011	6,518
Long-term debt, fair value	7,357	6,757
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	6,125	4,266
Long-term debt, fair value	6,728	4,908
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	1,884	1,598
Long-term debt, fair value	2,020	1,724
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	3,786	3,768
Long-term debt, fair value	$ 4,260	$ 4,219

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	$ 9,127	$ 2,700
Asset Impairment Charges	18	106	$ 81
Cinergy Receivables [Member]
Variable Interest Entity [Line Items]
Minimum Equity Balance required by Cinergy Receivables	$ 3
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Percent of proceeds received as cash	75.00%
Percent of proceeds received as subordinated note	25.00%
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Asset Impairment Charges	$ 71
Duke American Transmission Company [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Interest	50.00%
Pioneer Transmission [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Interest	50.00%
Duke Energy Carolinas [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	$ 1,600	500
Asset Impairment Charges	1	1	3
Duke Energy Progress [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	450	1,200
Asset Impairment Charges	1	5	(18)
Duke Energy Florida [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	1,894
Asset Impairment Charges	6	7	2
Duke Energy Florida [Member] | DEFPF [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	1,294
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	$ 250
Asset Impairment Charges			$ 94
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Variable Interest Entity [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Duke Energy Ohio [Member] | OVEC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Interest	9.00%
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Face Amount	$ 500
Asset Impairment Charges	$ 8	$ 88
Duke Energy Indiana [Member] | Cinergy Receivables [Member]
Variable Interest Entity [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%

Variable Interest Entities (Sch

Variable Interest Entities (Schedule of Accounts Receivable Securitizations)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Long-Term debt	$ 45,576	$ 36,842
Duke Energy Carolinas [Member]
Variable Interest Entity [Line Items]
Long-Term debt	9,187	7,711
Duke Energy Progress [Member]
Variable Interest Entity [Line Items]
Long-Term debt	6,409	6,366
Duke Energy Florida [Member]
Variable Interest Entity [Line Items]
Long-Term debt	$ 5,799	4,253
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Line of credit facility, expiration date	Dec. 1, 2018
Facility Size	$ 325
Long-Term debt	$ 325	325
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Line of credit facility, expiration date	Dec. 1, 2018
Facility Size	$ 425
Long-Term debt	$ 425	425
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Line of credit facility, expiration date	Feb. 1, 2019
Facility Size	$ 300
Long-Term debt	$ 300	254
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Line of credit facility, expiration date	Apr. 1, 2019
Facility Size	$ 225
Long-Term debt	$ 225	$ 225

Variable Interest Entities (Con

Variable Interest Entities (Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 392	$ 383	$ 463	$ 476
Restricted receivables of VIEs	1,893	1,748
Regulatory Assets, Current	1,023	877
Other current assets	458	307
Regulatory Assets, noncurrent	12,878	11,373
Investments and other assets	2,752	2,830
Total property, plant and equipment	121,397	109,967
Accumulated depreciation and amortization	(39,406)	(36,736)
Other deferred debits	17	43
Accounts payable	2,994	2,350
Current maturities of long-term debt	2,319	2,026
Other current liabilities	2,044	2,011
Long-Term debt	45,576	36,842
Deferred income taxes	14,155	12,548
Asset retirement obligations	10,200	10,249
Other Liabilities	1,753	1,631
Duke Energy Carolinas [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	14	13	13	23
Restricted receivables of VIEs	645	596
Regulatory Assets, Current	238	305
Other current assets	37	128
Regulatory Assets, noncurrent	3,159	2,766
Investments and other assets	940	999
Total property, plant and equipment	41,127	39,398
Accumulated depreciation and amortization	(14,365)	(13,521)
Other deferred debits	3	4
Accounts payable	833	753
Current maturities of long-term debt	116	356
Other current liabilities	468	519
Long-Term debt	9,187	7,711
Deferred income taxes	6,544	6,146
Asset retirement obligations	3,673	3,918
Other Liabilities	607	621
Duke Energy Progress [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	11	15	9	21
Restricted receivables of VIEs	404	349
Regulatory Assets, Current	188	264
Other current assets	57	121
Regulatory Assets, noncurrent	3,243	2,710
Investments and other assets	523	486
Total property, plant and equipment	28,419	27,313
Accumulated depreciation and amortization	(10,561)	(10,141)
Other deferred debits	2	3
Accounts payable	589	399
Current maturities of long-term debt	452	2
Other current liabilities	365	412
Long-Term debt	6,409	6,366
Deferred income taxes	3,323	3,027
Asset retirement obligations	4,508	4,567
Other Liabilities	51	45
Duke Energy Florida [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	16	8	$ 8	$ 16
Restricted receivables of VIEs	288	308
Regulatory Assets, Current	213	98
Other current assets	125	21
Regulatory Assets, noncurrent	2,480	2,725
Investments and other assets	276	292
Total property, plant and equipment	16,434	15,343
Accumulated depreciation and amortization	(4,644)	(4,720)
Other deferred debits	2	2
Accounts payable	413	322
Current maturities of long-term debt	326	13
Other current liabilities	352	452
Long-Term debt	5,799	4,253
Deferred income taxes	2,694	2,460
Asset retirement obligations	778	802
Other Liabilities	105	146
DEFPF [Member] | Duke Energy Florida [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	6
Regulatory Assets, Current	50
Other current assets	53
Regulatory Assets, noncurrent	1,142
Current maturities of long-term debt	62
Other current liabilities	17
Long-Term debt	1,217
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Other current assets	223	138
Total property, plant and equipment	3,419	2,015
Accumulated depreciation and amortization	(453)	(321)
Current maturities of long-term debt	198	108
Long-Term debt	1,097	968
Deferred income taxes	275	289
Other Liabilities	$ 252	$ 33

Variable Interest Entities (129

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 925	$ 499
Investments and other assets	2,752	2,830
Other current liabilities	2,044	2,011
Deferred credits and other liabilities	34,593	33,143
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	751	387
Investments and other assets	12
Total assets	763	387
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets of non-consolidated VIEs	747	370
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	487	113
Investments and other assets	12
Total assets	499	113
Net assets of non-consolidated VIEs	499	113
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	174	235
Total assets	174	235
Net assets of non-consolidated VIEs	174	235
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	90	39
Total assets	90	39
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets of non-consolidated VIEs	74	22
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	129	84
Investments and other assets	21	20
Other current liabilities	91	153
Deferred credits and other liabilities	1,978	1,998
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	82	47
Investments in equity method unconsolidated affiliates
Total assets	82	47
Net assets of non-consolidated VIEs	82	47
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	114	71
Other current liabilities	93	97
Deferred credits and other liabilities	3,749	3,219
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	101	60
Total assets	101	60
Net assets of non-consolidated VIEs	$ 101	$ 60

Variable Interest Entities (130

Variable Interest Entities (Schedule of Non-Consolidated VIE Pipeline Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 925	$ 499
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 751	387
Constitution Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	24.00%
Investments in equity method unconsolidated affiliates	$ 82
Sabal Trail Transmission Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	7.50%
Investments in equity method unconsolidated affiliates	$ 140	$ 61
Atlantic Coast Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	47.00%	40.00%
Investments in equity method unconsolidated affiliates	$ 265	$ 52
Atlantic Coast Pipeline [Member] | Piedmont Natural Gas [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage		7.00%
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 487	$ 113

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions)(Details) - Cinergy Receivables [Member] - Variable Interest Entity, Not Primary Beneficiary [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.50%	0.60%
Discount rate	1.50%	1.20%
Receivable turnover rate	13.30%	12.90%
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.50%	1.20%
Receivable turnover rate	10.60%	10.60%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold)(Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables sold	$ 267	$ 233
Less: retained interests	82	47
Net receivables sold	185	186
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables sold	306	260
Less: retained interests	101	60
Net receivables sold	$ 205	$ 200

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows)(Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables sold	$ 1,926	$ 1,963	$ 2,246
Loss recognized on sale	9	9	11
Cash proceeds from receivables sold	1,882	1,995	2,261
Collection fees received	1	1	1
Return received on retained interests	2	3	4
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables sold	2,635	2,627	2,913
Loss recognized on sale	11	11	11
Cash proceeds from receivables sold	2,583	2,670	2,932
Collection fees received	1	1	1
Return received on retained interests	$ 5	$ 5	$ 6

Common Stock (Earnings Per Shar

Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent									$ 2,571	$ 2,645	$ 2,533
Weighted Average Shares, Basic									691	694	707
Weighted Average Shares, Diluted									691	694	707
EPS, basic (usd per share)	$ 0.53	$ 1.44	$ 0.90	$ 0.83	$ 0.62	$ 1.29	$ 0.83	$ 1.06	$ 3.71	$ 3.80	$ 3.58
EPS, diluted (usd per share)	$ 0.53	$ 1.44	$ 0.90	$ 0.83	$ 0.62	$ 1.29	$ 0.83	$ 1.06	$ 3.71	$ 3.80	$ 3.58
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent									$ 2,567	$ 2,640	$ 2,529
Weighted Average Shares, Basic									691	694	707
Weighted Average Shares, Diluted									691	694	707
EPS, basic (usd per share)									$ 3.71	$ 3.80	$ 3.58
EPS, diluted (usd per share)									$ 3.71	$ 3.80	$ 3.58
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation									2	2	2
Dividends declared per share (usd per share)									$ 3.36	$ 3.24	$ 3.15

Common Stock (Accelerated Share

Common Stock (Accelerated Share Repurchase) (Details) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Jun. 30, 2015	Apr. 30, 2015	Dec. 31, 2015	Apr. 06, 2015
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount		$ 1,500
Payments for Repurchase of Common Stock		$ 1,500	$ 1,500
Delivered shares from Dealers	3.2	16.6	19.8
Fair Market Value of Delivered Shares	$ 225	$ 1,275	$ (1,500)
Percentage of ASR common stock received				85.00%
Accelerated Share Repurchases, Final Price Paid Per Share			$ 75.75
Goldman Sachs [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock		750
JPMorgan Chase [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock		$ 750

Common Stock (Equity Securities

Common Stock (Equity Securities Offering) (Details) - Piedmont Natural Gas [Member] - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Oct. 31, 2016
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered	10.6	10.6
Common stock issuances, including dividend reinvestment and employee benefits (in shares)	10.6
Proceeds from Issuance or Sale of Equity	$ 723

Severance (Narrative) (Details)

Severance (Narrative) (Details) - Employees	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
2016 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of eligible employees	600
2015 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of eligible employees		900

Severance (Expenses) (Details)

Severance (Expenses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
2016 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 118
2016 Severance Plan [Member] | Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	39
2016 Severance Plan [Member] | Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	40
2016 Severance Plan [Member] | Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	23
2016 Severance Plan [Member] | Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	17
2016 Severance Plan [Member] | Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	3
2016 Severance Plan [Member] | Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 7
2015 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		$ 142
2015 Severance Plan [Member] | Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		93
2015 Severance Plan [Member] | Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		36
2015 Severance Plan [Member] | Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		28
2015 Severance Plan [Member] | Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		8
2015 Severance Plan [Member] | Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		2
2015 Severance Plan [Member] | Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		$ 6

Severance (Rollforward) (Detail

Severance (Rollforward) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 136
Provision/adjustments	110
Cash reductions	(167)
Balance, end of period	79
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	78
Provision/adjustments	18
Cash reductions	(83)
Balance, end of period	13
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	23
Provision/adjustments	20
Cash reductions	(29)
Balance, end of period	14
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	19
Provision/adjustments	11
Cash reductions	(24)
Balance, end of period	6
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	4
Provision/adjustments	9
Cash reductions	(5)
Balance, end of period	$ 8

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for awards to employees and outside directors	10
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant date fair value of shares vested	$ 38	$ 41	$ 52
Unrecognized compensation cost	$ 27
Unrecognized compensation cost, period of recognition, years	1 year 10 months
Restricted Stock Units Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk Free Interest Rate	0.90%
Expected Volatility Rate	16.10%
Total grant date fair value of shares vested	$ 25	$ 26	$ 27
Unrecognized compensation cost	$ 24
Unrecognized compensation cost, period of recognition, years	1 year 10 months
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum option term, years	10 years

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	$ 35	$ 38	$ 38
Pretax stock-based compensation expense	55	61	61
Tax benefit associated with stock-based compensation expense	20	23	23
Stock-based compensation costs capitalized	2	3	4
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	36	38	39
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	19	23	22
Duke Energy Carolinas [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	12	14	12
Progress Energy [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	12	14	14
Duke Energy Progress [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	7	9	9
Duke Energy Florida [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	5	5	5
Duke Energy Ohio [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	2	2	5
Duke Energy Indiana [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense, Net of Tax	$ 3	$ 4	$ 3

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Stock Awards Outstanding) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock Units Awards [Member]
Schedule Of Shares Awarded [Abstract]
Shares awarded (in thousands)	684	524	557
Fair value	$ 52	$ 41	$ 40
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period	953
Granted	684	524	557
Vested	(525)
Forfeited	(86)
Outstanding at end of period	1,139	953
Stock awards expected to vest	1,056
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average fair value at beginning of period	$ 75
Granted	75
Vested	73
Forfeited	76
Weighted average fair value at end of period	76	$ 75
Weighted average fair value of awards expected to vest	$ 76
Performance Awards [Member]
Schedule Of Shares Awarded [Abstract]
Shares awarded (in thousands)	675	642	542
Fair value	$ 25	$ 26	$ 19
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period	1,697
Granted	675	642	542
Vested	(544)
Forfeited	(104)
Outstanding at end of period	1,724	1,697
Stock awards expected to vest	1,199
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average fair value at beginning of period	$ 40
Granted	38
Vested	46
Forfeited	38
Weighted average fair value at end of period	38	$ 40
Weighted average fair value of awards expected to vest	$ 38
Piedmont Natural Gas [Member] | Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Stock Awards Transfers In	113
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Stock Awards Transfers In Weighted Average Grant Date Fair Value	$ 79

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Options) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Option Activity, Options [Roll Forward]
Outstanding at beginning of period	103
Exercised	(103)
Outstanding at end of period	0	103
Stock Option Activity, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price of options outstanding at beginning of period	$ 69
Exercised	69
Weighted average exercise price of options outstanding end of period	$ 0	$ 69
Schedule Of Information Related To Stock Options [Abstract]
Intrinsic value of options exercised	$ 1	$ 5	$ 6
Tax benefit related to options exercised		2	2
Cash received from options exercised	$ 7	$ 17	$ 25

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Maximum years of participation	35 years
Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of securities on loan	$ 156	$ 305
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Expected long-term rate of return on plan assets		6.50%	6.75%
Qualified Pension Plans [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Master trust allocation percentage	98.00%
Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	10 years
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Expected long-term rate of return on plan assets	6.50%	6.50%	6.75%
Other Post-Retirement Benefit Plans [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Master trust allocation percentage	2.00%
Expected long-term rate of return on plan assets	6.50%
Other Post-Retirement Benefit Plans [Member] | Piedmont Pension and OPEB Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	6.75%
Duke Energy Carolinas [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Duke Energy Carolinas [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Duke Energy Carolinas [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	11 years
Progress Energy [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Progress Energy [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	14 years
Progress Energy [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Duke Energy Progress [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Duke Energy Progress [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	12 years
Duke Energy Progress [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Duke Energy Florida [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Duke Energy Florida [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	15 years
Duke Energy Florida [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	8 years
Duke Energy Ohio [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Duke Energy Ohio [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Duke Energy Ohio [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	8 years
Duke Energy Indiana [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years
Duke Energy Indiana [Member] | Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	7 years
Duke Energy Indiana [Member] | Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period, in years	9 years

Employee Benefit Plans (Contrib

Employee Benefit Plans (Contributions to Defined Benefit Pension Plans) (Details) - Qualified Pension Plans [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 155	$ 302
Anticipated contribution	160
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	43	91
Anticipated contribution	45
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	43	83
Anticipated contribution	45
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	24	42
Anticipated contribution	25
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	20	40
Anticipated contribution	20
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	5	8
Anticipated contribution	4
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	9	$ 19
Anticipated contribution	$ 9

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	$ 8	$ 9	$ 10
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	147	159	135
Interest cost on projected benefit obligation	335	324	344
Expected return on plan assets	(519)	(516)	(511)
Amortization of actuarial loss (gain)	134	166	150
Amortization of prior service cost (credit)	(17)	(15)	(15)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	3
Other	8	8	8
Net periodic costs	91	126	111
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	48	50	41
Interest cost on projected benefit obligation	86	83	85
Expected return on plan assets	(142)	(139)	(132)
Amortization of actuarial loss (gain)	33	39	36
Amortization of prior service cost (credit)	(8)	(7)	(8)
Other	2	2	2
Net periodic costs	19	28	24
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	42	44	40
Interest cost on projected benefit obligation	106	104	112
Expected return on plan assets	(168)	(171)	(173)
Amortization of actuarial loss (gain)	51	65	68
Amortization of prior service cost (credit)	(3)	(3)	(3)
Other	3	3	3
Net periodic costs	31	42	47
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	24	23	21
Interest cost on projected benefit obligation	49	48	54
Expected return on plan assets	(82)	(79)	(85)
Amortization of actuarial loss (gain)	23	33	32
Amortization of prior service cost (credit)	(2)	(2)	(2)
Other	1	1	1
Net periodic costs	13	24	21
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	19	20	20
Interest cost on projected benefit obligation	55	54	57
Expected return on plan assets	(84)	(87)	(85)
Amortization of actuarial loss (gain)	29	31	32
Amortization of prior service cost (credit)	(1)	(1)	(1)
Other	1	1	1
Net periodic costs	19	18	24
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	4	4	5
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	4	4	4
Interest cost on projected benefit obligation	19	18	20
Expected return on plan assets	(27)	(26)	(27)
Amortization of actuarial loss (gain)	4	7	4
Other	1
Net periodic costs	1	3	1
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	9	10	9
Interest cost on projected benefit obligation	28	27	29
Expected return on plan assets	(42)	(42)	(41)
Amortization of actuarial loss (gain)	11	13	13
Amortization of prior service cost (credit)	(1)	1
Other	1	1	1
Net periodic costs	6	10	11
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	3	3
Interest cost on projected benefit obligation	14	13	14
Amortization of actuarial loss (gain)	8	6	3
Amortization of prior service cost (credit)	(1)	(1)	(1)
Net periodic costs	23	21	19
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1	1	1
Amortization of actuarial loss (gain)	1
Net periodic costs	2	1	1
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1
Interest cost on projected benefit obligation	5	4	5
Amortization of actuarial loss (gain)	1	2	2
Amortization of prior service cost (credit)		(1)	(1)
Net periodic costs	6	6	7
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			1
Interest cost on projected benefit obligation	1	1	1
Amortization of actuarial loss (gain)	1	1
Net periodic costs	2	2	2
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2	2
Amortization of actuarial loss (gain)	1	2
Net periodic costs	3	4	2
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Amortization of actuarial loss (gain)		1
Net periodic costs		1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	8	10	9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3	6	10
Interest cost on projected benefit obligation	35	36	49
Expected return on plan assets	(12)	(13)	(13)
Amortization of actuarial loss (gain)	6	16	39
Amortization of prior service cost (credit)	(141)	(140)	(125)
Net periodic costs	(109)	(95)	(40)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	2
Interest cost on projected benefit obligation	8	9	12
Expected return on plan assets	(8)	(8)	(9)
Amortization of actuarial loss (gain)	(3)	(2)	3
Amortization of prior service cost (credit)	(14)	(14)	(11)
Net periodic costs	(16)	(14)	(3)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	4
Interest cost on projected benefit obligation	15	15	22
Amortization of actuarial loss (gain)	22	28	42
Amortization of prior service cost (credit)	(103)	(102)	(95)
Net periodic costs	(65)	(58)	(27)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1
Interest cost on projected benefit obligation	8	8	11
Amortization of actuarial loss (gain)	13	18	31
Amortization of prior service cost (credit)	(68)	(68)	(73)
Net periodic costs	(47)	(41)	(30)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	3
Interest cost on projected benefit obligation	7	7	12
Amortization of actuarial loss (gain)	9	10	10
Amortization of prior service cost (credit)	(35)	(35)	(21)
Net periodic costs	(18)	(17)	4
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	2	3	2
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1	2	2
Expected return on plan assets		(1)
Amortization of actuarial loss (gain)	(2)	(2)	(2)
Net periodic costs	(1)	(1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1
Interest cost on projected benefit obligation	4	4	5
Expected return on plan assets	(1)	(1)	(1)
Amortization of actuarial loss (gain)	(1)	(2)
Amortization of prior service cost (credit)	(1)
Net periodic costs	$ 1	$ 2	$ 5

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss	$ 11	$ 13	$ (4)
Progress Energy [Member]
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss	(1)	10	$ (9)
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	53	1
Regulatory liabilities, net increase (decrease)	(114)	(92)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	(2)	2
Actuarial (gains) losses arising during the year	3	(5)
Prior year service cost (credit) arising during the year		(3)
Amortization of Prior Year Prior Service Credit	1	3
Net amount recognized in accumulated other comprehensive (income) loss	2	(3)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)	(22)	(8)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	47	1
Regulatory liabilities, net increase (decrease)	(51)	(71)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(1)
Actuarial (gains) losses arising during the year		2
Amortization of Prior Year Prior Service Credit	1	(1)
Net amount recognized in accumulated other comprehensive (income) loss	1
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	38
Regulatory liabilities, net increase (decrease)	(25)	(36)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	9	1
Regulatory liabilities, net increase (decrease)	(26)	(35)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)	(2)	2
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(6)	(7)
Regulatory liabilities, net increase (decrease)	(12)	(8)
Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	214	173
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	4	6
Actuarial (gains) losses arising during the year		4
Prior year service cost (credit) arising during the year	(2)	1
Amortization of prior year actuarial gains (losses)	(7)	(11)
Defined Benefit Plan Amounts Transferred with Midwest Generation Disposal Group		3
Reclassification of actuarial gains (losses) to regulatory assets		(6)
Net amount recognized in accumulated other comprehensive (income) loss	(5)	(3)
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	4	65
Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	34	18
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		5
Amortization of prior year actuarial gains (losses)	(1)	(4)
Net amount recognized in accumulated other comprehensive (income) loss	(1)	1
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	18	14
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	16	4
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	2	14
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	9	11
Non Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(3)	(13)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(7)
Actuarial (gains) losses arising during the year	1	17
Prior year service cost (credit) arising during the year	(1)	1
Net amount recognized in accumulated other comprehensive (income) loss		11
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(2)	2
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	2	(16)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(5)
Actuarial (gains) losses arising during the year		13
Net amount recognized in accumulated other comprehensive (income) loss		8
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	1	(1)
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	1	(15)
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	$ (1)	$ (1)

Employee Benefit Plans (Project

Employee Benefit Plans (Projected Benefit Obligations Reconciliation of Funded Status to Net Amount Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in Projected Benefit Obligation [Rollforward]
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	$ 352
Settlements	(6)
Change in Fair Value of Plan Assets [Rollforward]
Assets received from acquisition	343
Impact of Settlements	(6)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Changes		$ (83)
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	7,727	8,107
Service cost	147	159	$ 135
Interest cost on projected benefit obligation	335	324	344
Actuarial (gains) losses	307	(241)
Plan amendments	(52)	(6)
Benefits paid	(679)	(533)
Obligation at measurement date	8,131	7,727	8,107
Accumulated benefit obligation at measurement date	8,006	7,606
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(8,136)	(8,498)
Defined Benefit Plan, Divestitures, Plan Assets		(81)
Actual return on plan assets	582	(50)
Benefits paid	(679)	(533)
Employer contributions	155	302
Plan assets at measurement date	(8,531)	(8,136)	(8,498)
Funded status of plan	400	409
Pension Plan [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,995	2,053
Service cost	48	50	41
Interest cost on projected benefit obligation	86	83	85
Actuarial (gains) losses	46	(53)
Transfers of benefit obligation	14	8
Plan amendments	(3)
Benefits paid	(234)	(146)
Obligation at measurement date	1,952	1,995	2,053
Accumulated benefit obligation at measurement date	1,952	1,993
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(2,243)	(2,300)
Actual return on plan assets	159	(10)
Benefits paid	(234)	(146)
Employer contributions	43	91
Transfer of plan assets	14	8
Plan assets at measurement date	(2,225)	(2,243)	(2,300)
Funded status of plan	273	248
Pension Plan [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	2,451	2,557
Service cost	42	44	40
Interest cost on projected benefit obligation	106	104	112
Actuarial (gains) losses	111	(111)
Transfers of benefit obligation	3	4
Benefits paid	(195)	(147)
Obligation at measurement date	2,512	2,451	2,557
Accumulated benefit obligation at measurement date	2,479	2,414
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(2,640)	(2,722)
Actual return on plan assets	190	(22)
Benefits paid	(195)	(147)
Employer contributions	43	83
Transfer of plan assets	(3)	4
Plan assets at measurement date	(2,675)	(2,640)	(2,722)
Funded status of plan	163	189
Pension Plan [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,143	1,187
Service cost	24	23	21
Interest cost on projected benefit obligation	49	48	54
Actuarial (gains) losses	52	(46)
Transfers of benefit obligation	3	7
Benefits paid	(107)	(76)
Obligation at measurement date	1,158	1,143	1,187
Accumulated benefit obligation at measurement date	1,158	1,143
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(1,284)	(1,321)
Actual return on plan assets	92	(10)
Benefits paid	(107)	(76)
Employer contributions	24	42
Transfer of plan assets	(3)	7
Plan assets at measurement date	(1,290)	(1,284)	(1,321)
Funded status of plan	132	141
Pension Plan [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,276	1,335
Service cost	19	20	20
Interest cost on projected benefit obligation	55	54	57
Actuarial (gains) losses	57	(62)
Transfers of benefit obligation		3
Benefits paid	(84)	(68)
Obligation at measurement date	1,323	1,276	1,335
Accumulated benefit obligation at measurement date	1,290	1,240
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(1,321)	(1,363)
Actual return on plan assets	95	(11)
Benefits paid	(84)	(68)
Employer contributions	20	40
Transfer of plan assets		(3)
Plan assets at measurement date	(1,352)	(1,321)	(1,363)
Funded status of plan	29	45
Pension Plan [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	453	469
Service cost	4	4	4
Interest cost on projected benefit obligation	19	18	20
Actuarial (gains) losses	13	(9)
Transfers of benefit obligation	3	8
Plan amendments	(3)
Benefits paid	(36)	(37)
Obligation at measurement date	447	453	469
Accumulated benefit obligation at measurement date	436	442
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(433)	(456)
Actual return on plan assets	29	(2)
Benefits paid	(36)	(37)
Employer contributions	5	8
Transfer of plan assets	(3)	8
Plan assets at measurement date	(428)	(433)	(456)
Funded status of plan	(19)	(20)
Pension Plan [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	649	673
Service cost	9	10	9
Interest cost on projected benefit obligation	28	27	29
Actuarial (gains) losses	41	(15)
Plan amendments	(15)	(4)
Benefits paid	(54)	(42)
Obligation at measurement date	658	649	673
Accumulated benefit obligation at measurement date	649	628
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(655)	(681)
Actual return on plan assets	47	(3)
Benefits paid	(54)	(42)
Employer contributions	9	19
Plan assets at measurement date	(657)	(655)	(681)
Funded status of plan	(1)	6
Non Qualified Pension Plans [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	341	337
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	5
Service cost	2	3	3
Interest cost on projected benefit obligation	14	13	14
Actuarial (gains) losses	4	10
Transfers of benefit obligation		4
Plan amendments	2
Benefits paid	(32)	(26)
Obligation at measurement date	332	341	337
Accumulated benefit obligation at measurement date	332	336
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(32)	(26)
Employer contributions	32	26
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	16	16
Interest cost on projected benefit obligation	1	1	1
Actuarial (gains) losses	(1)	1
Benefits paid	(2)	(2)
Obligation at measurement date	14	16	16
Accumulated benefit obligation at measurement date	14	16
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(2)	(2)
Employer contributions	2	2
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	112	116
Service cost		1	1
Interest cost on projected benefit obligation	5	4	5
Actuarial (gains) losses	5	(1)
Benefits paid	(8)	(8)
Obligation at measurement date	114	112	116
Accumulated benefit obligation at measurement date	114	112
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(8)	(8)
Employer contributions	8	8
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	33	35
Service cost			1
Interest cost on projected benefit obligation	1	1	1
Actuarial (gains) losses	2
Benefits paid	(3)	(3)
Obligation at measurement date	33	33	35
Accumulated benefit obligation at measurement date	33	33
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(3)	(3)
Employer contributions	3	3
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	46	61
Interest cost on projected benefit obligation	2	2	2
Actuarial (gains) losses	1	(14)
Benefits paid	(3)	(3)
Obligation at measurement date	46	46	61
Accumulated benefit obligation at measurement date	46	46
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(3)	(3)
Employer contributions	3	3
Non Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	4	4
Obligation at measurement date	4	4	4
Accumulated benefit obligation at measurement date	4	4
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	5	5
Actuarial (gains) losses	(2)
Obligation at measurement date	3	5	5
Accumulated benefit obligation at measurement date	3	5
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Changes	39
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	828	916
Service cost	3	6	10
Interest cost on projected benefit obligation	35	36	49
Plan participants' contributions	19	20
Actuarial (gains) losses	33	(39)
Plan amendments	(1)	(9)
Benefits paid	(88)	(100)
Accrued retiree drug subsidy		1
Obligation at measurement date	868	828	916
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(208)	(227)
Defined Benefit Plan, Divestitures, Plan Assets		(3)
Assets received from acquisition	29
Actual return on plan assets	14	(1)
Benefits paid	(88)	(100)
Employer contributions	62	62
Plan participants' contributions	19	20
Plan assets at measurement date	(244)	(208)	(227)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	200	220
Service cost	1	1	2
Interest cost on projected benefit obligation	8	9	12
Plan participants' contributions	3	4
Actuarial (gains) losses	5	(18)
Transfers of benefit obligation	1	2
Benefits paid	(17)	(18)
Obligation at measurement date	201	200	220
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(134)	(145)
Actual return on plan assets	8	(1)
Benefits paid	(17)	(18)
Employer contributions	9	4
Plan participants' contributions	3	4
Plan assets at measurement date	(137)	(134)	(145)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	354	379
Service cost	1	1	4
Interest cost on projected benefit obligation	15	15	22
Plan participants' contributions	7	7
Actuarial (gains) losses	16	(1)
Benefits paid	(36)	(47)
Obligation at measurement date	357	354	379
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date
Actual return on plan assets	1	1
Benefits paid	(36)	(47)
Employer contributions	29	39
Plan participants' contributions	7	7
Plan assets at measurement date	(1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	188	207
Service cost		1	1
Interest cost on projected benefit obligation	8	8	11
Plan participants' contributions	4	4
Actuarial (gains) losses	8	(13)
Benefits paid	(17)	(19)
Obligation at measurement date	191	188	207
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date		(1)
Actual return on plan assets		1
Benefits paid	(17)	(19)
Employer contributions	13	15
Plan participants' contributions	4	4
Plan assets at measurement date			(1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	164	170
Service cost	1	1	3
Interest cost on projected benefit obligation	7	7	12
Plan participants' contributions	3	3
Actuarial (gains) losses	8	11
Benefits paid	(19)	(28)
Obligation at measurement date	164	164	170
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(1)
Actual return on plan assets		1
Benefits paid	(19)	(28)
Employer contributions	15	25
Plan participants' contributions	3	3
Plan assets at measurement date		(1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	35	39
Interest cost on projected benefit obligation	1	2	2
Plan participants' contributions	1	1
Actuarial (gains) losses		(3)
Plan amendments	(1)	(1)
Benefits paid	(4)	(3)
Obligation at measurement date	32	35	39
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(8)	(8)
Actual return on plan assets	1
Benefits paid	(4)	(3)
Employer contributions	1	2
Plan participants' contributions	1	1
Plan assets at measurement date	(7)	(8)	(8)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	87	96
Service cost		1	1
Interest cost on projected benefit obligation	4	4	5
Plan participants' contributions	2	2
Actuarial (gains) losses	3	1
Plan amendments		(4)
Benefits paid	(13)	(13)
Obligation at measurement date	83	87	96
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(19)	(23)
Actual return on plan assets	2	(1)
Benefits paid	(13)	(13)
Employer contributions	12	8
Plan participants' contributions	2	2
Plan assets at measurement date	$ (22)	$ (19)	$ (23)

Employee Benefit Plans (Amou149

Employee Benefit Plans (Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	$ 1,111	$ 1,088
Regulatory assets	13,901	12,250
Regulatory liabilities	7,290	6,655
Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	97	107
Regulatory assets	3,397	3,071
Regulatory liabilities	3,001	2,841
Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	547	536
Regulatory assets	6,123	5,797
Regulatory liabilities	2,584	2,673
Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	252	262
Regulatory assets	3,431	2,974
Regulatory liabilities	2,104	1,963
Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	262	242
Regulatory assets	2,693	2,823
Regulatory liabilities	479	709
Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	56	56
Regulatory assets	557	533
Regulatory liabilities	257	257
Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	71	80
Regulatory assets	1,222	818
Regulatory liabilities	788	816
Pension Plan [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	518	474
Noncurrent pension liability	118	65
Net amount recognized	400	409
Regulatory assets	2,098	1,884
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(41)	(45)
Prior year service cost (credit) arising during the year	(6)	(4)
Net actuarial loss (gain)	123	130
Net amount recognized in accumulated other comprehensive income (loss)	76	81
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	147
Unrecognized prior service (credit) cost	(24)
Pension Plan [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	273	252
Noncurrent pension liability		4
Net amount recognized	273	248
Regulatory assets	476	472
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	31
Unrecognized prior service (credit) cost	(8)
Pension Plan [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	225	232
Noncurrent pension liability	62	43
Net amount recognized	163	189
Regulatory assets	805	771
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(6)	(6)
Net actuarial loss (gain)	16	17
Net amount recognized in accumulated other comprehensive income (loss)	10	11
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	52
Unrecognized prior service (credit) cost	(3)
Pension Plan [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	132	145
Noncurrent pension liability		4
Net amount recognized	132	141
Regulatory assets	378	360
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	23
Unrecognized prior service (credit) cost	(2)
Pension Plan [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	91	84
Noncurrent pension liability	62	39
Net amount recognized	29	45
Regulatory assets	426	410
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	29
Unrecognized prior service (credit) cost	(1)
Pension Plan [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	6	1
Noncurrent pension liability	25	21
Net amount recognized	(19)	(20)
Regulatory assets	81	79
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	5
Pension Plan [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension		6
Noncurrent pension liability	1
Net amount recognized	(1)	6
Regulatory assets	171	162
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	8
Unrecognized prior service (credit) cost	(2)
Brazilian Retirement Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Net amount recognized in accumulated other comprehensive income (loss)		13
Non-Qualified Pension Plans [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	28	27
Noncurrent pension liability	304	314
Total accrued pension liability	332	341
Regulatory assets	73	76
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(3)	(3)
Prior year service cost (credit) arising during the year	(1)
Net actuarial loss (gain)	10	9
Net amount recognized in accumulated other comprehensive income (loss)	6	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	7
Unrecognized prior service (credit) cost	(2)
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	12	14
Total accrued pension liability	14	16
Regulatory assets	5	7
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	8	8
Noncurrent pension liability	106	104
Total accrued pension liability	114	112
Regulatory assets	18	16
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(3)	(3)
Net actuarial loss (gain)	9	9
Net amount recognized in accumulated other comprehensive income (loss)	6	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	2
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	3
Noncurrent pension liability	31	30
Total accrued pension liability	33	33
Regulatory assets	7	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	3	3
Noncurrent pension liability	43	43
Total accrued pension liability	46	46
Regulatory assets	11	10
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0
Noncurrent pension liability	4	4
Total accrued pension liability	4	4
Regulatory assets	1	1
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0
Noncurrent pension liability	3	5
Total accrued pension liability	3	5
Regulatory assets	0	1
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	38	37
Noncurrent pension liability	586	583
Total accrued pension liability	624	620
Regulatory assets	54	1
Regulatory liabilities	174	288
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	5	7
Prior year service cost (credit) arising during the year	(5)	(6)
Net actuarial loss (gain)	(10)	(13)
Net amount recognized in accumulated other comprehensive income (loss)	(10)	(12)
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	10
Unrecognized prior service (credit) cost	(115)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	64	66
Total accrued pension liability	64	66
Regulatory liabilities	46	68
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(2)
Unrecognized prior service (credit) cost	(10)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	31	31
Noncurrent pension liability	325	323
Total accrued pension liability	356	354
Regulatory assets	48	1
Regulatory liabilities		51
Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior year service cost (credit) arising during the year		(1)
Net amount recognized in accumulated other comprehensive income (loss)		(1)
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	21
Unrecognized prior service (credit) cost	(85)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	17	16
Noncurrent pension liability	174	172
Total accrued pension liability	191	188
Regulatory assets	38
Regulatory liabilities		25
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	12
Unrecognized prior service (credit) cost	(55)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	15	15
Noncurrent pension liability	149	149
Total accrued pension liability	164	164
Regulatory assets	10	1
Regulatory liabilities		26
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	9
Unrecognized prior service (credit) cost	(30)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	23	25
Total accrued pension liability	25	27
Regulatory liabilities	19	21
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(2)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	63	68
Total accrued pension liability	63	68
Regulatory assets	51	57
Regulatory liabilities	71	$ 83
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(6)
Unrecognized prior service (credit) cost	$ (1)

Employee Benefit Plans (Informa

Employee Benefit Plans (Information For Plans with Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Qualified Pension Plans [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 1,299	$ 1,216
Accumulated benefit obligation	1,239	1,158
Fair value of plan assets	(1,182)	(1,151)
Qualified Pension Plans [Member] | Progress Energy [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	665	611
Accumulated benefit obligation	633	575
Fair value of plan assets	(604)	(574)
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	665	611
Accumulated benefit obligation	633	575
Fair value of plan assets	(604)	(574)
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	311	307
Accumulated benefit obligation	299	298
Fair value of plan assets	(286)	(289)
Non-Qualified Pension Plans [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	332	341
Accumulated benefit obligation	332	336
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	14	16
Accumulated benefit obligation	14	16
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	114	112
Accumulated benefit obligation	114	112
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	33	33
Accumulated benefit obligation	33	33
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	46	46
Accumulated benefit obligation	46	46
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	4	4
Accumulated benefit obligation	4	4
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	3	5
Accumulated benefit obligation	$ 3	$ 5

Employee Benefit Plans (Assumpt

Employee Benefit Plans (Assumptions Used For Pension Benefits Accounting) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Qualified Pension Plans [Member]
Benefit Obligations [Abstract]
Discount rate	4.10%	4.40%	4.10%
Net Periodic Benefit Cost [Abstract]
Discount rate	4.40%	4.10%	4.70%
Expected long-term rate of return on plan assets		6.50%	6.75%
Qualified Pension Plans [Member] | Minimum [Member]
Benefit Obligations [Abstract]
Salary increase	4.00%	4.00%	4.00%
Net Periodic Benefit Cost [Abstract]
Discount rate
Salary increase	4.00%	4.00%	4.00%
Expected long-term rate of return on plan assets	6.50%
Qualified Pension Plans [Member] | Maximum [Member]
Benefit Obligations [Abstract]
Salary increase	4.50%	4.40%	4.40%
Net Periodic Benefit Cost [Abstract]
Salary increase	4.40%	4.40%	4.40%
Expected long-term rate of return on plan assets	6.75%
Non-Qualified Pension Plans [Member]
Benefit Obligations [Abstract]
Discount rate	4.10%	4.40%	4.10%
Salary increase	4.40%	4.40%	4.40%
Net Periodic Benefit Cost [Abstract]
Discount rate	4.40%	4.10%	4.70%
Salary increase	4.40%	4.40%	4.40%
Other Post-Retirement Benefit Plans [Member]
Benefit Obligations [Abstract]
Discount rate	4.10%	4.40%	4.10%
Net Periodic Benefit Cost [Abstract]
Discount rate	4.40%	4.10%	4.70%
Expected long-term rate of return on plan assets	6.50%	6.50%	6.75%
Assumed tax rate	35.00%	35.00%	35.00%

Employee Benefit Plans (Assumed

Employee Benefit Plans (Assumed Health Care Cost Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	7.00%	7.50%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	4.75%	4.75%
Year that the rate reaches the ultimate trend rate	2,023	2,023

Employee Benefit Plans (Sensiti

Employee Benefit Plans (Sensitivity to Changes in Assumed Health Care Cost Trend Rates) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	$ 1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	29
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(25)
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	7
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(6)
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	12
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(10)
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	6
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(6)
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	5
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(5)
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(1)
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	3
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	$ (2)

Employee Benefit Plans (Expecte

Employee Benefit Plans (Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2016USD ($)
Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	$ 585
2,018	595
2,019	613
2,020	632
2,021	637
2022-2026	3,099
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	162
2,018	171
2,019	177
2,020	186
2,021	181
2022-2026	867
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	159
2,018	159
2,019	164
2,020	171
2,021	175
2022-2026	890
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	84
2,018	83
2,019	86
2,020	90
2,021	92
2022-2026	455
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	74
2,018	75
2,019	76
2,020	79
2,021	81
2022-2026	425
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	35
2,018	33
2,019	33
2,020	34
2,021	35
2022-2026	161
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	49
2,018	49
2,019	48
2,020	47
2,021	48
2022-2026	219
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	29
2,018	25
2,019	25
2,020	24
2,021	24
2022-2026	111
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	2
2,018	2
2,019	2
2,020	2
2,021	1
2022-2026	5
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	8
2,018	8
2,019	8
2,020	8
2,021	8
2022-2026	36
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	3
2,018	3
2,019	2
2,020	2
2,021	2
2022-2026	11
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	3
2,018	3
2,019	3
2,020	3
2,021	3
2022-2026	15
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2022-2026	1
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2022-2026	1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	85
2,018	81
2,019	78
2,020	75
2,021	72
2022-2026	310
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	18
2,018	18
2,019	18
2,020	18
2,021	18
2022-2026	76
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	32
2,018	31
2,019	31
2,020	30
2,021	29
2022-2026	126
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	17
2,018	16
2,019	16
2,020	16
2,021	15
2022-2026	67
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	15
2,018	15
2,019	14
2,020	14
2,021	13
2022-2026	58
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	4
2,018	3
2,019	3
2,020	3
2,021	3
2022-2026	12
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,017	10
2,018	9
2,019	9
2,020	8
2,021	7
2022-2026	$ 31

Employee Benefit Plans (Target

Employee Benefit Plans (Target and Actual Asset Allocations) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	100.00%	100.00%
Target allocation	100.00%
Master Trust [Member] | US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	11.00%	11.00%
Target allocation	10.00%
Master Trust [Member] | Non US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	8.00%	8.00%
Target allocation	8.00%
Master Trust [Member] | Global Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	10.00%	10.00%
Target allocation	10.00%
Master Trust [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	63.00%	63.00%
Target allocation	63.00%
Master Trust [Member] | Global Private Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	2.00%
Target allocation	3.00%
Master Trust [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	2.00%
Target allocation	2.00%
Master Trust [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	2.00%
Target allocation	2.00%
Master Trust [Member] | Other Global Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	2.00%
Target allocation	2.00%
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	100.00%	100.00%
Target allocation	100.00%
OPEB [Member] | US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	39.00%	29.00%
Target allocation	38.00%
OPEB [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	22.00%	43.00%
Target allocation	15.00%
OPEB [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	37.00%	28.00%
Target allocation	45.00%
OPEB [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	2.00%	0.00%
Target allocation	2.00%
Piedmont Pension and OPEB Assets [Member] | US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	61.00%
Target allocation	60.00%
Piedmont Pension and OPEB Assets [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocation	39.00%
Target allocation	40.00%

Employee Benefit Plans (Fair Va

Employee Benefit Plans (Fair Value Measurements of Plan Assets - Master Retirement Trust) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ (8,655)	$ (8,243)
Alternative Investments, Fair Value Disclosure	1,300	1,201
Master Trust [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(1,929)	(1,636)
Master Trust [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(5,388)	(5,375)
Master Trust [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(38)	(31)
Master Trust [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(2,472)	(2,160)
Alternative Investments, Fair Value Disclosure	759	688
Master Trust [Member] | Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(1,677)	(1,470)
Master Trust [Member] | Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(27)	(2)
Master Trust [Member] | Equity Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(9)
Master Trust [Member] | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(4,330)	(4,362)
Master Trust [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(8)
Master Trust [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(4,322)	(4,362)
Master Trust [Member] | Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(476)	(404)
Master Trust [Member] | Short Term Investments [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(211)	(192)
Master Trust [Member] | Short Term Investments [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(265)	(212)
Master Trust [Member] | Partnership Interest [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(157)	(185)
Alternative Investments, Fair Value Disclosure	157	185
Master Trust [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(232)	(210)
Alternative Investments, Fair Value Disclosure	232	210
Master Trust [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(144)	(118)
Alternative Investments, Fair Value Disclosure	127	118
Master Trust [Member] | Real Estate [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(17)
Master Trust [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(734)	(748)
Master Trust [Member] | US Treasury and Government [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(734)	(748)
Master Trust [Member] | Guaranteed Investment Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(29)	(31)
Master Trust [Member] | Guaranteed Investment Contracts [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(29)	(31)
Master Trust [Member] | Government Bonds - Foreign [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(32)	(34)
Master Trust [Member] | Government Bonds - Foreign [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(32)	(34)
Master Trust [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(17)	(10)
Master Trust [Member] | Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(15)	(10)
Master Trust [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(2)
Master Trust [Member] | Asset Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets		(9)
Master Trust [Member] | Asset Backed Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets		(9)
Master Trust [Member] | Miscellaneous Investments And Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(32)	(28)
Alternative Investments, Fair Value Disclosure	25
Master Trust [Member] | Miscellaneous Investments And Other [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(1)	(36)
Master Trust [Member] | Miscellaneous Investments And Other [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(6)	(8)
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(66)	(42)
OPEB [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(66)	(42)
OPEB [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(26)	(12)
OPEB [Member] | Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(26)	(12)
OPEB [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(1)
OPEB [Member] | Real Estate [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(1)
OPEB [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(14)	(18)
OPEB [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(14)	(18)
OPEB [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	(25)	(12)
OPEB [Member] | Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ (25)	$ (12)
Duke Energy Carolinas [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	27.00%	28.00%
Progress Energy [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	30.00%	32.00%
Duke Energy Progress [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	15.00%	15.00%
Duke Energy Florida [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	15.00%	16.00%
Duke Energy Ohio [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	5.00%	5.00%
Duke Energy Indiana [Member] | Master Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Allocated assets	8.00%	8.00%

Employee Benefit Plans (Reconci

Employee Benefit Plans (Reconciliation of Assets Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 15	$ 4
Purchases	33	24
Sales		(1)
Total gains (losses) and other, net		(21)
Ending balance	(161)	15
Master Trust [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	31	34
Sales	(2)	(2)
Total gains (losses) and other, net	0	(1)
Ending balance	38	$ 31
Piedmont Natural Gas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases	(187)
Piedmont Natural Gas [Member] | Master Trust [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Ending balance	$ (9)

Employee Benefit Plans (Employe

Employee Benefit Plans (Employee Savings Plans)(Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		$ 169	$ 159	$ 143
Employee Savings Plans [Abstract]
Matching contribution percentage		100.00%
Eligible pay percentage		6.00%
Additional contribution percentage for employees not participating in defined pension plans		4.00%
Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		$ 155	302
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		57	54	47
Duke Energy Carolinas [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		43	91
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		50	48	43
Progress Energy [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		43	83
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		35	34	30
Duke Energy Progress [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		24	42
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		15	13	14
Duke Energy Florida [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		20	40
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		3	3	3
Duke Energy Ohio [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		5	8
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized		8	7	$ 7
Duke Energy Indiana [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Employer contributions		$ 9	$ 19
Piedmont Natural Gas [Member]
Employee Savings Plans [Abstract]
Eligible pay percentage		5.00%
Additional contribution percentage for employees not participating in defined pension plans		4.00%
Piedmont Natural Gas [Member] | Pension Plan [Member]
Employee Savings Plans [Abstract]
Eligible pay percentage		4.00%
Piedmont Natural Gas [Member] | Pension Plan [Member] | Subsequent Event [Member]
Employee Savings Plans [Abstract]
Employer contributions	$ 2.2

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current state taxes	$ (15)	$ (12)	$ 56
Current foreign taxes	2	4	6
Total current income taxes	(13)	(8)	62
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	1,064	1,097	1,144
Deferred state taxes	117	181	35
Total deferred income taxes	1,181	1,278	1,179
Investment tax credit amortization	(12)	(14)	(16)
Income tax expense (benefit) from continuing operations	1,156	1,256	1,225
Tax expense (benefit) from discontinued operations	(30)	89	149
Total income tax expense included in Consolidated Statements of Operations	1,126	1,345	1,374
Net operating loss utilization			1,544
Net operating loss carry forward	648	264
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Domestic	3,689	3,831	3,637
Foreign	45	79	126
Total income from continuing operations before income taxes	3,734	3,910	3,763
Taxes on Foreign Earnings [Abstract]
Undistributed Earnings of Foreign Subsidiaries			2,700
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			373
Duke Energy Carolinas [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	139	216	161
Current state taxes	25	14	51
Total current income taxes	164	230	212
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	430	345	407
Deferred state taxes	45	57	(25)
Total deferred income taxes	475	402	382
Investment tax credit amortization	(5)	(5)	(6)
Income tax expense (benefit) from continuing operations	634	627	588
Total income tax expense included in Consolidated Statements of Operations	634	627	588
Net operating loss utilization			345
Net operating loss carry forward	4	15
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	1,800	1,708	1,660
Progress Energy [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	15	(193)	(466)
Current state taxes	(19)	1	(8)
Total current income taxes	(4)	(192)	(474)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	486	694	938
Deferred state taxes	50	27	84
Total deferred income taxes	536	721	1,022
Investment tax credit amortization	(5)	(7)	(8)
Income tax expense (benefit) from continuing operations	527	522	540
Tax expense (benefit) from discontinued operations	1	(1)	(4)
Total income tax expense included in Consolidated Statements of Operations	528	521	536
Net operating loss utilization			530
Net operating loss carry forward	190	119
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	1,566	1,587	1,420
Duke Energy Progress [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(59)	(56)	(184)
Current state taxes	(25)	(4)	14
Total current income taxes	(84)	(60)	(170)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	350	334	436
Deferred state taxes	40	27	25
Total deferred income taxes	390	361	461
Investment tax credit amortization	(5)	(7)	(6)
Income tax expense (benefit) from continuing operations	301	294	285
Total income tax expense included in Consolidated Statements of Operations	301	294	285
Net operating loss utilization			291
Net operating loss carry forward	60	21
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	900	860	752
Duke Energy Florida [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	76	1	(53)
Current state taxes	22	(7)	1
Total current income taxes	98	(6)	(52)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	199	290	350
Deferred state taxes	25	58	52
Total deferred income taxes	224	348	402
Investment tax credit amortization			(1)
Income tax expense (benefit) from continuing operations	322	342	349
Total income tax expense included in Consolidated Statements of Operations	322	342	349
Net operating loss utilization			64
Net operating loss carry forward	49	84
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	873	941	897
Duke Energy Ohio [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(7)	(18)	(73)
Current state taxes	(13)	(1)	3
Total current income taxes	(20)	(19)	(70)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	88	96	113
Deferred state taxes	11	5	1
Total deferred income taxes	99	101	114
Investment tax credit amortization	(1)	(1)	(1)
Income tax expense (benefit) from continuing operations	78	81	43
Tax expense (benefit) from discontinued operations	(36)	22	(300)
Total income tax expense included in Consolidated Statements of Operations	42	103	(257)
Net operating loss utilization			56
Net operating loss carry forward	26	3
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	270	230	111
Duke Energy Indiana [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	7	(86)	(112)
Current state taxes	6	(12)	1
Total current income taxes	13	(98)	(111)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	202	245	294
Deferred state taxes	11	17	15
Total deferred income taxes	213	262	309
Investment tax credit amortization	(1)	(1)	(1)
Income tax expense (benefit) from continuing operations	225	163	197
Total income tax expense included in Consolidated Statements of Operations	225	163	197
Net operating loss utilization			141
Net operating loss carry forward	58	45
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	606	$ 479	$ 556
Previously Remitted Earnings [Member]
Taxes on Foreign Earnings [Abstract]
Foreign Income Tax Expense (Benefit)	$ (95)

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 1,307	$ 1,369	$ 1,317
State income tax, net of federal income tax effect	64	109	59
AFUDC equity income	(70)	(58)	(47)
Renewable energy production tax credits	(97)	(72)	(67)
Audit Adjustment	5	(22)
Tax true-up	(14)	2
Other items, net	(39)	(72)	(37)
Income tax expense (benefit) from continuing operations	$ 1,156	$ 1,256	$ 1,225
Effective tax rate	31.00%	32.10%	32.60%
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 630	$ 598	$ 581
State income tax, net of federal income tax effect	46	46	17
AFUDC equity income	(36)	(34)	(32)
Audit Adjustment	3
Tax true-up	(14)	2
Other items, net	5	15	22
Income tax expense (benefit) from continuing operations	$ 634	$ 627	$ 588
Effective tax rate	35.20%	36.70%	35.40%
Progress Energy [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 548	$ 555	$ 497
State income tax, net of federal income tax effect	20	18	49
AFUDC equity income	(26)	(19)	(9)
Renewable energy production tax credits		(1)
Audit Adjustment		(23)
Tax true-up	(11)	(3)
Other items, net	(4)	(5)	3
Income tax expense (benefit) from continuing operations	$ 527	$ 522	$ 540
Effective tax rate	33.70%	32.90%	38.00%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 315	$ 302	$ 263
State income tax, net of federal income tax effect	10	15	25
AFUDC equity income	(17)	(17)	(9)
Audit Adjustment		1
Tax true-up	(3)	(4)
Other items, net	(4)	(3)	6
Income tax expense (benefit) from continuing operations	$ 301	$ 294	$ 285
Effective tax rate	33.40%	34.20%	37.90%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 306	$ 330	$ 314
State income tax, net of federal income tax effect	30	33	34
AFUDC equity income	(9)	(3)
Audit Adjustment		(24)
Tax true-up	(9)	2
Other items, net	4	4	1
Income tax expense (benefit) from continuing operations	$ 322	$ 342	$ 349
Effective tax rate	36.90%	36.30%	38.90%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 95	$ 81	$ 39
State income tax, net of federal income tax effect	(2)	2	3
AFUDC equity income	(2)	(1)	(1)
Tax true-up	(16)	(5)
Other items, net	3	4	2
Income tax expense (benefit) from continuing operations	$ 78	$ 81	$ 43
Effective tax rate	28.90%	35.20%	38.90%
Duke Energy Indiana [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 212	$ 168	$ 195
State income tax, net of federal income tax effect	11	2	10
AFUDC equity income	(6)	(4)	(5)
Tax true-up	2	(9)
Other items, net	6	6	(3)
Income tax expense (benefit) from continuing operations	$ 225	$ 163	$ 197
Effective tax rate	37.10%	34.00%	35.50%

Income Taxes (Deferred Income T

Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Jan. 01, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		$ 382	$ 201
Capital lease obligations		60	63
Pension, postretirement and other employee benefits		561	580
Progress Energy merger purchase accounting adjustments		918	1,009
Tax credits and NOL carryforwards		4,682	3,631
Other		205	206
Valuation allowance		(96)	(93)
Total deferred income tax assets		6,712	5,597
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(1,892)	(1,573)
Accelerated depreciation rates		(14,872)	(12,939)
Regulatory assets and deferred debits, net		(4,103)	(3,633)
Total deferred income tax liabilities		(20,867)	(18,145)
Net deferred income tax liabilities		(14,155)	(12,548)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		4,682	3,631
Valuation allowance		(96)	(93)
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(14,155)	(12,548)
State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Net reduction in deferred tax liability		80	95
Investment Tax Credits [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		1,143
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		$ 1,143
Investment Tax Credits [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2027
Investment Tax Credits [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2036
Alternative Minimum Tax Credit [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		$ 1,151
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		1,151
NOL Carryforwards [Member] | Federal [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		1,267
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		$ 1,267
NOL Carryforwards [Member] | Federal [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2020
NOL Carryforwards [Member] | Federal [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2036
NOL Carryforwards [Member] | State [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		$ 248
Valuation allowance		(84)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		248
Valuation allowance		$ (84)
NOL Carryforwards [Member] | State [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2017
NOL Carryforwards [Member] | State [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2036
NOL Carryforwards [Member] | Foreign Jurisdictions [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		$ 12
Valuation allowance		(12)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		12
Valuation allowance		$ (12)
NOL Carryforwards [Member] | Foreign Jurisdictions [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2026
NOL Carryforwards [Member] | Foreign Jurisdictions [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2036
Foreign Tax Credit [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		$ 859
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		$ 859
Foreign Tax Credit [Member] | Foreign Jurisdictions [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2024
Foreign Tax Credit [Member] | Foreign Jurisdictions [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2026
charitable carryforwards [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards		$ 2
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		$ 2
charitable carryforwards [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2017
charitable carryforwards [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year		Dec. 31, 2019
Duke Energy Carolinas [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		$ 66	38
Capital lease obligations		8	9
Pension, postretirement and other employee benefits		16	46
Tax credits and NOL carryforwards		192	170
Other		16	20
Total deferred income tax assets		298	283
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(1,149)	(1,057)
Accelerated depreciation rates		(4,664)	(4,429)
Regulatory assets and deferred debits, net		(1,029)	(943)
Total deferred income tax liabilities		(6,842)	(6,429)
Net deferred income tax liabilities		(6,544)	(6,146)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		192	170
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(6,544)	(6,146)
Progress Energy [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		126	115
Pension, postretirement and other employee benefits		199	186
Tax credits and NOL carryforwards		1,165	997
Other		35	48
Valuation allowance		(12)	(38)
Total deferred income tax assets		1,513	1,308
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(597)	(412)
Accelerated depreciation rates		(4,490)	(4,169)
Regulatory assets and deferred debits, net		(1,672)	(1,517)
Total deferred income tax liabilities		(6,759)	(6,098)
Net deferred income tax liabilities		(5,246)	(4,790)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		1,165	997
Valuation allowance		(12)	(38)
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(5,246)	(4,790)
Duke Energy Progress [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		40	25
Pension, postretirement and other employee benefits		91	92
Tax credits and NOL carryforwards		222	163
Other		8	2
Total deferred income tax assets		361	282
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(313)	(228)
Accelerated depreciation rates		(2,479)	(2,325)
Regulatory assets and deferred debits, net		(892)	(756)
Total deferred income tax liabilities		(3,684)	(3,309)
Net deferred income tax liabilities		(3,323)	(3,027)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		222	163
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(3,323)	(3,027)
Duke Energy Florida [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		93	66
Pension, postretirement and other employee benefits		96	82
Tax credits and NOL carryforwards		232	177
Other			46
Total deferred income tax assets		421	371
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(297)	(201)
Accelerated depreciation rates		(2,038)	(1,868)
Regulatory assets and deferred debits, net		(780)	(762)
Total deferred income tax liabilities		(3,115)	(2,831)
Net deferred income tax liabilities		(2,694)	(2,460)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		232	177
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(2,694)	(2,460)
Duke Energy Ohio [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		21	29
Pension, postretirement and other employee benefits		22	24
Tax credits and NOL carryforwards		49	25
Investments and other assets		3	3
Other		5	37
Total deferred income tax assets		100	118
Deferred Tax Liabilities, Gross [Abstract]
Accelerated depreciation rates		(1,404)	(1,356)
Regulatory assets and deferred debits, net		(139)	(169)
Total deferred income tax liabilities		(1,543)	(1,525)
Net deferred income tax liabilities		(1,443)	(1,407)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		49	25
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		(1,443)	(1,407)
Duke Energy Indiana [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities		4	5
Capital lease obligations		1	2
Pension, postretirement and other employee benefits		37	40
Tax credits and NOL carryforwards		278	215
Other		9	20
Total deferred income tax assets		329	282
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(21)	(7)
Accelerated depreciation rates		(1,938)	(1,797)
Regulatory assets and deferred debits, net		(270)	(135)
Total deferred income tax liabilities		(2,229)	(1,939)
Net deferred income tax liabilities		(1,900)	(1,657)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards		278	215
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Net deferred income tax liabilities		$ (1,900)	$ (1,657)
January 2015 [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate			5.00%
January 2015 [Member] | Duke Energy Carolinas [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate			5.00%
January 2015 [Member] | Duke Energy Progress [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate			5.00%
January 2016 [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate		4.00%
January 2016 [Member] | Duke Energy Carolinas [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate		4.00%
January 2016 [Member] | Duke Energy Progress [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate		4.00%
Scenario, Forecast [Member] | January 2017 [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate	3.00%
Scenario, Forecast [Member] | January 2017 [Member] | Duke Energy Carolinas [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate	3.00%
Scenario, Forecast [Member] | January 2017 [Member] | Duke Energy Progress [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Statutory Tax Rate	3.00%

Income Taxes (Other Disclosures

Income Taxes (Other Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	$ 88	$ 213	$ 230
Gross decreases-tax positions in prior periods	(4)	(48)	(2)
Decreases due to settlements	(68)	(45)	(15)
Reduction due to lapse of statute of limitations	1	(32)
Total changes	(71)	(125)	(17)
Unrecognized Tax Benefits - December 31	17	88	213
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	8
Amount that if recognized, would affect the effective tax rate or regulatory liability	8
Amount that if recognized, would be recorded as a component of discontinued operations	5
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		12	6
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest receivable related to income taxes		3
Interest payable related to income taxes	4		13
Duke Energy Carolinas [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	72	160	171
Gross decreases-tax positions in prior periods	(4)	(45)
Decreases due to settlements	(67)	(43)	(11)
Total changes	(71)	(88)	(11)
Unrecognized Tax Benefits - December 31	1	72	160
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	1
Amount that if recognized, would affect the effective tax rate or regulatory liability	1
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest expense recognized related to income taxes	7	1	1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	23	14	13
Progress Energy [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	1	32	32
Gross increases-tax positions in prior periods		1	1
Gross decreases-tax positions in prior periods	(1)
Decreases due to settlements			(1)
Reduction due to lapse of statute of limitations	2	(32)
Total changes	1	(31)
Unrecognized Tax Benefits - December 31	2	1	32
Amount that if recognized, would affect the effective tax rate or regulatory liability	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	1	2	3
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	1		5
Duke Energy Progress [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	3	23	22
Gross increases-tax positions in prior periods		1	1
Gross decreases-tax positions in prior periods	(1)
Reduction due to lapse of statute of limitations		(21)
Total changes	(1)	(20)	1
Unrecognized Tax Benefits - December 31	2	3	23
Amount that if recognized, would affect the effective tax rate or regulatory liability	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		2
Net interest expense recognized related to income taxes			1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	1	1	3
Duke Energy Florida [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1		8	8
Reduction due to lapse of statute of limitations		(8)
Total changes		(8)
Unrecognized Tax Benefits - December 31			8
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	2	1	1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes			5
Duke Energy Ohio [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross increases-tax positions in prior periods	4
Total changes	4
Unrecognized Tax Benefits - December 31	4
Amount that if recognized, would be recorded as a component of discontinued operations	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes			4
Duke Energy Indiana [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	1	1	1
Decreases due to settlements	(1)
Total changes	$ (1)
Unrecognized Tax Benefits - December 31		1	1
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		1	4
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest receivable related to income taxes		$ 3	$ 2

Other Income and Expenses, N163

Other Income and Expenses, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	$ 21	$ 20	$ 16
AFUDC equity	200	164	135
Post in-service equity returns	67	73	89
Nonoperating income (expense), other	36	33	80
Other income and expenses, net	324	290	320
Duke Energy Carolinas [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	4	2	4
AFUDC equity	102	96	91
Post in-service equity returns	55	60	71
Nonoperating income (expense), other	1	2	6
Other income and expenses, net	162	160	172
Progress Energy [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	4	4	3
AFUDC equity	76	54	26
Post in-service equity returns	12	13	17
Nonoperating income (expense), other	22	26	31
Other income and expenses, net	114	97	77
Duke Energy Progress [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	3	2
AFUDC equity	50	47	25
Post in-service equity returns	12	13	17
Nonoperating income (expense), other	6	9	9
Other income and expenses, net	71	71	51
Duke Energy Florida [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	2	2	2
AFUDC equity	26	7
Nonoperating income (expense), other	16	15	18
Other income and expenses, net	44	24	20
Duke Energy Ohio [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	5	4	8
AFUDC equity	6	3	4
Nonoperating income (expense), other	(2)	(1)	(2)
Other income and expenses, net	9	6	10
Duke Energy Indiana [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	6	6	6
AFUDC equity	16	11	14
Nonoperating income (expense), other		(6)	2
Other income and expenses, net	$ 22	$ 11	$ 22

Quarterly Financial Data (Un164

Quarterly Financial Data (Unaudited) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 5,577	$ 6,576	$ 5,213	$ 5,377	$ 5,075	$ 6,202	$ 5,302	$ 5,792	$ 22,743	$ 22,371	$ 22,509
Operating income (loss)	888	1,954	1,259	1,240	890	1,606	1,192	1,390	5,341	5,078	4,842
Income (loss) from continuing operations	376	1,001	624	577	433	890	576	755	2,578	2,654	2,538
Income (Loss) From Discontinued Operations, net of tax	(598)	180	(112)	122	49	45	(29)	112	(408)	177	(649)
Net Income (Loss)	(222)	1,181	512	699	482	935	547	867	2,170	2,831	1,889
Net Income (Loss) Attributable to Parent	$ (227)	$ 1,176	$ 509	$ 694	$ 477	$ 932	$ 543	$ 864	$ 2,152	$ 2,816	$ 1,883
Income (loss) from continuing operations attributable to Duke Energy Corporation common shareholders [Abstract]
Basic	$ 0.53	$ 1.44	$ 0.90	$ 0.83	$ 0.62	$ 1.29	$ 0.83	$ 1.06	$ 3.71	$ 3.80	$ 3.58
Diluted	0.53	1.44	0.90	0.83	0.62	1.29	0.83	1.06	3.71	3.80	3.58
Income (loss) from discontinued operations attributable To Duke Energy Corporation common shareholders [Abstract]
Basic	(0.86)	0.26	(0.16)	0.18	0.07	0.06	(0.05)	0.16	(0.60)	0.25	(0.92)
Diluted	(0.86)	0.26	(0.16)	0.18	0.07	0.06	(0.05)	0.16	(0.60)	0.25	(0.92)
Net income attributable to Duke Energy Corporation common shareholders [Abstract]
Basic	(0.33)	1.70	0.74	1.01	0.69	1.35	0.78	1.22	3.11	4.05	2.66
Diluted	$ (0.33)	$ 1.70	$ 0.74	$ 1.01	$ 0.69	$ 1.35	$ 0.78	$ 1.22	$ 3.11	$ 4.05	$ 2.66
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 1,681	$ 2,226	$ 1,675	$ 1,740	$ 1,560	$ 2,061	$ 1,707	$ 1,901	$ 7,322	$ 7,229	$ 7,351
Operating income (loss)	302	815	464	481	296	666	483	515	2,062	1,960	1,895
Net Income (Loss) Attributable to Parent	140	494	261	271	141	383	265	292	1,166	1,081	1,072
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	2,208	2,965	2,348	2,332	2,336	2,929	2,476	2,536	9,853	10,277	10,166
Operating income (loss)	292	814	560	475	351	756	504	549	2,141	2,160	2,018
Income (loss) from continuing operations	104	449	274	212	132	452	217	264	1,039	1,065	880
Income (Loss) From Discontinued Operations, net of tax									2	(3)	(6)
Net Income (Loss)	106	449	274	212	131	451	217	263	1,041	1,062	874
Net Income (Loss) Attributable to Parent	104	446	272	209	128	448	215	260	1,031	1,051	869
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,174	1,583	1,213	1,307	1,160	1,488	1,193	1,449	5,277	5,290	5,176
Operating income (loss)	135	438	255	258	130	394	184	316	1,086	1,024	935
Net Income (Loss) Attributable to Parent	60	271	131	137	69	229	85	183	599	566	467
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,030	1,381	1,133	1,024	1,174	1,436	1,281	1,086	4,568	4,977	4,975
Operating income (loss)	155	373	300	213	216	357	315	227	1,041	1,115	1,078
Net Income (Loss) Attributable to Parent	64	206	171	110	105	216	165	113	551	599	548
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	511	489	428	516	452	462	405	586	1,944	1,905	1,913
Operating income (loss)	90	106	55	96	73	76	43	111	347	303	187
Income (loss) from continuing operations									192	149	68
Income (Loss) From Discontinued Operations, net of tax		34		2		(2)	(65)	90	36	23	(563)
Net Income (Loss) Attributable to Parent	57	89	23	59	43	32	(52)	149	228	172	(495)
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	733	809	702	714	667	749	686	788	2,958	2,890	3,175
Operating income (loss)	176	239	174	176	171	117	146	210	765	644	705
Net Income (Loss) Attributable to Parent	$ 72	$ 129	$ 85	$ 95	$ 94	$ 46	$ 68	$ 108	$ 381	$ 316	$ 359

Quarterly Financial Data (Un165

Quarterly Financial Data (Unaudited) (Unusual or Infrequently Occurring Items) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	$ (208)	$ (84)	$ (111)	$ (120)	$ (30)	$ (24)	$ (22)	$ (21)	$ (523)	$ (97)
Asset Impairment Charges									(18)	(106)	$ (81)
Cost Savings Initiative	(29)	(19)	(24)	(20)	(142)				(92)	(142)
Total	(751)	(174)	(329)	(140)	(182)	(121)	(63)	(21)	(1,394)	(387)
Commercial Renewables Impairment [Member]
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charges		(71)							(71)
Edwardsport Settlement [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(3)	(90)				(93)
Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(7)	(7)				(14)
Midwest Generation Business [Member]
Quarterly Financial Information Disclosure [Line Items]
State Tax Adjustment related to Midwest Generation Sale							(41)			(41)
Central America Impairment [Member]
Quarterly Financial Information Disclosure [Line Items]
Asset Impairment Charges			(194)						(194)
Intl Disposal Group [Member]
Quarterly Financial Information Disclosure [Line Items]
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax	514								514
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(68)	(13)	(12)	(11)	(16)	(11)	(11)	(9)	(104)	(47)
Asset Impairment Charges									(1)	(1)	(3)
Cost Savings Initiative	(11)	(8)	(10)	(10)	(93)				(39)	(93)
Total	(79)	(21)	(22)	(21)	(116)	(12)	(11)	(9)	(143)	(148)
Duke Energy Carolinas [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					(7)	(1)				(8)
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(44)	(10)	(8)	(7)	(10)	(8)	(8)	(8)	(69)	(34)
Asset Impairment Charges									(7)	(12)	16
Cost Savings Initiative	(14)	(10)	(8)	(8)	(36)				(40)	(36)
Total	(58)	(20)	(16)	(15)	(46)	(14)	(8)	(8)	(109)	(76)
Progress Energy [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties						(6)				(6)
Duke Energy Progress [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(40)	(6)	(5)	(5)	(6)	(6)	(5)	(5)	(56)	(22)
Asset Impairment Charges									(1)	(5)	18
Cost Savings Initiative	(6)	(7)	(5)	(5)	(28)				(23)	(28)
Total	(46)	(13)	(10)	(10)	(34)	(12)	(5)	(5)	(79)	(56)
Duke Energy Progress [Member] | Ash Basin [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties						(6)				(6)
Duke Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(4)	(4)	(3)	(2)	(4)	(3)	(3)	(3)	(13)	(13)
Asset Impairment Charges									(6)	(7)	(2)
Cost Savings Initiative	(9)	(3)	(3)	(2)	(8)				(17)	(8)
Total	(13)	(7)	(6)	(4)	(12)	(3)	(3)	(3)	(30)	(21)
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(2)	(2)	(1)	(1)	(1)	(1)	(1)	(1)	(6)	(4)
Asset Impairment Charges											$ (94)
Cost Savings Initiative	(1)		(1)	(1)	(2)				(3)	(2)
Total	(3)	(2)	(2)	(2)	(3)	(1)	(1)	(1)	(9)	(6)
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Costs to achieve mergers	(3)	(3)	(2)	(1)	(2)	(2)	(1)	(2)	(9)	(7)
Asset Impairment Charges									(8)	(88)
Cost Savings Initiative	(1)	(1)	(4)	(1)	(6)				(7)	(6)
Total	$ (4)	$ (4)	$ (6)	$ (2)	(11)	(92)	$ (1)	$ (2)	$ (16)	(106)
Duke Energy Indiana [Member] | Edwardsport Settlement [Member]
Quarterly Financial Information Disclosure [Line Items]
Settlements and penalties					$ (3)	$ (90)				$ (93)