Income Taxes (Deferred Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	188	$ 245
Capital lease obligations	63	59
Pension, postretirement and other employee benefits	546	649
Progress Energy merger purchase accounting adjustments	1,124	1,184
Tax credits and NOL carryforwards	3,540	4,307
Other		265
Valuation allowance	(184)	(192)
Total deferred income tax assets	5,277	6,517
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(1,625)	(1,396)
Accelerated depreciation rates	(11,715)	(12,615)
Regulatory assets and deferred debits	(3,694)	(3,185)
Other	(44)
Total deferred income tax liabilities	(17,078)	(17,196)
Net deferred income tax liabilities	(11,801)	(10,679)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	3,540	4,307
Valuation allowance	(184)	(192)
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	1,593	1,373
Investments and Other Assets: Other	29	45
Deferred Credits and Other Liabilities: Other	(13,423)	(12,097)
Net deferred income tax liabilities	(11,801)	(10,679)
Investment Tax Credits [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	581
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	581
Investment Tax Credits [Member] | Minimum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2029
Investment Tax Credits [Member] | Maximum [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2034
Alternative Minimum Tax Credit [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	1,093
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	1,093
NOL Carryforwards [Member] | Federal [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	749
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	749
NOL Carryforwards [Member] | State [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	162
Valuation allowance	(79)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	162
Valuation allowance	(79)
NOL Carryforwards [Member] | Foreign Jurisdictions [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	117
Valuation allowance	(105)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	117
Valuation allowance	(105)
NOL Carryforwards [Member] | Minimum [Member] | Federal [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2030
NOL Carryforwards [Member] | Minimum [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2015
NOL Carryforwards [Member] | Minimum [Member] | Foreign Jurisdictions [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2015
NOL Carryforwards [Member] | Maximum [Member] | Federal [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2033
NOL Carryforwards [Member] | Maximum [Member] | State [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2034
NOL Carryforwards [Member] | Maximum [Member] | Foreign Jurisdictions [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2033
Foreign Tax Credit [Member]
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	838
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	838
Foreign Tax Credit [Member] | Minimum [Member] | Foreign Jurisdictions [Member]
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Expiration year	Dec. 31, 2024
Duke Energy Carolinas [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	53	56
Capital lease obligations	10	11
Pension, postretirement and other employee benefits	4	18
Tax credits and NOL carryforwards	157	488
Other	12	15
Total deferred income tax assets	236	588
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(1,051)	(999)
Accelerated depreciation rates	(4,046)	(4,400)
Regulatory assets and deferred debits	(953)	(609)
Total deferred income tax liabilities	(6,050)	(6,008)
Net deferred income tax liabilities	(5,814)	(5,420)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	157	488
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	3	286
Current Liabilities: Other	(5)
Deferred Credits and Other Liabilities: Other	(5,812)	(5,706)
Net deferred income tax liabilities	(5,814)	(5,420)
Progress Energy [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	108	136
Pension, postretirement and other employee benefits	188	341
Tax credits and NOL carryforwards	980	1,965
Other		116
Valuation allowance	(13)	(40)
Total deferred income tax assets	1,263	2,518
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(427)	(209)
Accelerated depreciation rates	(3,284)	(3,663)
Regulatory assets and deferred debits	(1,602)	(1,389)
Other	(151)
Total deferred income tax liabilities	(5,464)	(5,261)
Net deferred income tax liabilities	(4,201)	(2,743)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	980	1,965
Valuation allowance	(13)	(40)
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	558	540
Deferred Credits and Other Liabilities: Other	(4,759)	(3,283)
Net deferred income tax liabilities	(4,201)	(2,743)
Duke Energy Progress [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	28	9
Pension, postretirement and other employee benefits	96	119
Tax credits and NOL carryforwards	91	396
Other	55	39
Valuation allowance	(1)	(1)
Total deferred income tax assets	269	562
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(232)	(160)
Accelerated depreciation rates	(2,030)	(2,528)
Regulatory assets and deferred debits	(809)	(202)
Total deferred income tax liabilities	(3,071)	(2,890)
Net deferred income tax liabilities	(2,802)	(2,328)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	91	396
Valuation allowance	(1)	(1)
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	106	229
Deferred Credits and Other Liabilities: Other	(2,908)	(2,557)
Net deferred income tax liabilities	(2,802)	(2,328)
Duke Energy Florida [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	78	96
Pension, postretirement and other employee benefits	93	145
Tax credits and NOL carryforwards	252	365
Other		43
Total deferred income tax assets	423	649
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(245)	(49)
Accelerated depreciation rates	(1,252)	(1,160)
Regulatory assets and deferred debits	(792)	(1,159)
Other	(246)
Total deferred income tax liabilities	(2,535)	(2,368)
Net deferred income tax liabilities	(2,112)	(1,719)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	252	365
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	340	110
Deferred Credits and Other Liabilities: Other	(2,452)	(1,829)
Net deferred income tax liabilities	(2,112)	(1,719)
Duke Energy Ohio [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	(8)	(13)
Pension, postretirement and other employee benefits	17	23
Tax credits and NOL carryforwards	38	165
Investments and other assets	14
Other	35	20
Total deferred income tax assets	96	195
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets		(17)
Accelerated depreciation rates	(1,660)	(1,937)
Regulatory assets and deferred debits	(141)	(168)
Total deferred income tax liabilities	(1,801)	(2,122)
Net deferred income tax liabilities	(1,705)	(1,927)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	38	165
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	60	85
Deferred Credits and Other Liabilities: Other	(1,765)	(2,012)
Net deferred income tax liabilities	(1,705)	(1,927)
Duke Energy Indiana [Member]
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	12	9
Capital lease obligations	2	(2)
Pension, postretirement and other employee benefits	43	54
Tax credits and NOL carryforwards	260	521
Other	11	14
Total deferred income tax assets	328	596
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(4)	(7)
Accelerated depreciation rates	(1,603)	(1,591)
Regulatory assets and deferred debits	(106)	(117)
Total deferred income tax liabilities	(1,713)	(1,715)
Net deferred income tax liabilities	(1,385)	(1,119)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	260	521
Classification of Deferred Tax Assets (Liabiliities) in the Consolidated Balance Sheets [Abstract]
Current Assets: Other	206	52
Deferred Credits and Other Liabilities: Other	(1,591)	(1,171)
Net deferred income tax liabilities	(1,385)	$ (1,119)