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