Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 350	$ 390
Investments and other assets	3,287	3,432
Other current liabilities	1,868	1,996
Deferred credits and other liabilities	31,250	26,575
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)
Investments in equity method unconsolidated affiliates	152	213
Intangibles, net		96
Investments and other assets	4	4
Total assets	156	313
Other current liabilities	2	3
Deferred credits and other liabilities	14	15
Total liabilities	16	18
Net assets (liabilities)	140	295
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)
Investments in equity method unconsolidated affiliates	149	153
Intangibles, net
Investments and other assets
Total assets	149	153
Other current liabilities
Deferred credits and other liabilities
Total liabilities
Net assets (liabilities)	149	153
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)
Investments in equity method unconsolidated affiliates	3	60
Intangibles, net		96
Investments and other assets	4	4
Total assets	7	160
Other current liabilities	2	3
Deferred credits and other liabilities	14	15
Total liabilities	16	18
Net assets (liabilities)	(9)	142
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Investments and other assets	20	232
Other current liabilities	79	110
Deferred credits and other liabilities	2,300	2,546
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)	49	114
Investments in equity method unconsolidated affiliates
Intangibles, net		96
Investments and other assets
Total assets	49	210
Other current liabilities
Deferred credits and other liabilities
Total liabilities
Net assets (liabilities)	49	210
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Investments and other assets	214	269
Other current liabilities	116	88
Deferred credits and other liabilities	2,573	2,334
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)	76	143
Investments in equity method unconsolidated affiliates
Intangibles, net
Investments and other assets
Total assets	76	143
Other current liabilities
Deferred credits and other liabilities
Total liabilities
Net assets (liabilities)	$ 76	$ 143