Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Unsecured Debt	12,937	13,550
Secured Debt	2,806	2,559
First mortgage bonds	19,180	17,831
Capital leases	1,428	1,516
Other debt		8
Tax exempt bonds	1,296	2,356
Notes Payable And Commercial Paper	2,989	1,289
Fair value hedge carrying value adjustment	8	9
Unamortized debt discount and premium, net	1,890	1,977
Total debt	42,534	41,095
Short-term notes payable and commercial paper	(2,514)	(839)
Current maturities of long-term debt	(2,807)	(2,104)
Total long-term debt	37,213	38,152
Short term obligations classified as long-term debt	1,022	1,121
Unsecured Debt [Member]
Debt Instrument [Line Items]
Weighted-average rate	4.92%	5.18%
Debt maturity date, start	Dec. 31, 2015	Dec. 31, 2014
Debt maturity date, end	Dec. 31, 2073	Dec. 31, 2039
Secured Debt [Member]
Debt Instrument [Line Items]
Weighted-average rate	2.50%	2.69%
Debt maturity date, start	Dec. 31, 2016	Dec. 31, 2014
Debt maturity date, end	Dec. 31, 2037	Dec. 31, 2037
First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-average rate	4.76%	4.90%
Debt maturity date, start	Dec. 31, 2015	Dec. 31, 2015
Debt maturity date, end	Dec. 31, 2044	Dec. 31, 2043
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Weighted-average rate	5.30%	5.23%
Debt maturity date, start	Dec. 31, 2015	Dec. 31, 2014
Debt maturity date, end	Dec. 31, 2051	Dec. 31, 2051
Other Debt [Member]
Debt Instrument [Line Items]
Weighted-average rate		4.77%
Debt maturity date, end		Dec. 31, 2027
Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Weighted-average rate	2.13%	1.28%
Debt maturity date, start	Dec. 31, 2015	Dec. 31, 2014
Debt maturity date, end	Dec. 31, 2041	Dec. 31, 2041
Short term obligations classified as long-term debt	347	471
Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Weighted-average rate	0.70%	1.02%
Weighted-average days to maturity	27 days	49 days
Short term obligations classified as long-term debt	475	450
Revolving Loan [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	200	200
Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	1,975	2,067
Total Debt [Member]
Debt Instrument [Line Items]
Weighted-average rate	4.29%	4.52%
Long-term Debt [Member]
Debt Instrument [Line Items]
Weighted-average rate	4.58%	4.59%
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,155	1,157
Secured Debt	400	400
First mortgage bonds	6,161	6,161
Capital leases	27	30
Tax exempt bonds	355	395
Money pool borrowings	300	300
Fair value hedge carrying value adjustment	8	9
Unamortized debt discount and premium, net	(15)	(16)
Total debt	8,391	8,436
Current maturities of long-term debt	(507)	(47)
Total long-term debt	7,884	8,389
Short term obligations classified as long-term debt	335	375
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	35	75
Duke Energy Carolinas [Member] | Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Progress Energy [Member]
Debt Instrument [Line Items]
Unsecured Debt	3,850	4,150
Secured Debt	525	305
First mortgage bonds	9,800	8,450
Capital leases	314	327
Tax exempt bonds	291	910
Money pool borrowings	835	1,213
Unamortized debt discount and premium, net	(26)	(27)
Total debt	15,589	15,328
Short-term money pool borrowings	(835)	(1,213)
Current maturities of long-term debt	(1,507)	(485)
Total long-term debt	13,247	13,630
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Secured Debt	300	305
First mortgage bonds	5,475	4,125
Capital leases	146	148
Tax exempt bonds	291	669
Money pool borrowings		462
Unamortized debt discount and premium, net	(11)	(12)
Total debt	6,201	5,697
Short-term money pool borrowings		(462)
Current maturities of long-term debt	(945)	(174)
Total long-term debt	5,256	5,061
Duke Energy Progress [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	129	144
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Unsecured Debt	150	150
Secured Debt	225
First mortgage bonds	4,325	4,325
Capital leases	168	179
Tax exempt bonds		241
Money pool borrowings	84	181
Unamortized debt discount and premium, net	(8)	(9)
Total debt	4,944	5,067
Short-term money pool borrowings	(84)	(181)
Current maturities of long-term debt	(562)	(11)
Total long-term debt	4,298	4,875
Duke Energy Florida [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	787	838
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Unsecured Debt	773	805
First mortgage bonds	900	900
Capital leases	20	27
Other debt		8
Tax exempt bonds	77	479
Money pool borrowings	516	43
Unamortized debt discount and premium, net	(29)	(31)
Total debt	2,257	2,231
Short-term money pool borrowings	(491)	(43)
Current maturities of long-term debt	(157)	(47)
Total long-term debt	1,609	2,141
Short term obligations classified as long-term debt	52	111
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27	111
Duke Energy Ohio [Member] | Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Unsecured Debt	742	744
First mortgage bonds	2,319	2,319
Capital leases	16	20
Tax exempt bonds	573	573
Money pool borrowings	221	150
Unamortized debt discount and premium, net	(9)	(10)
Total debt	3,862	3,796
Short-term money pool borrowings	(71)
Current maturities of long-term debt	(5)	(5)
Total long-term debt	3,786	3,791
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] | Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150