Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 499	$ 358
Investments and other assets	3,042	3,008
Other current liabilities	2,115	2,188
Other liabilities	32,490	31,364
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	387	188
Investments and other assets		4
Total assets	387	192
Other current liabilities	3	3
Other liabilities	14	14
Total liabilities	17	17
Net assets of non-consolidated VIEs	370	175
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	235	150
Total assets	235	150
Net assets of non-consolidated VIEs	235	150
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	152	38
Investments and other assets		4
Total assets	152	42
Other current liabilities	3	3
Other liabilities	14	14
Total liabilities	17	17
Net assets of non-consolidated VIEs	135	25
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Investments and other assets	20	23
Other current liabilities	153	66
Other liabilities	1,998	2,281
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	47	91
Total assets	47	91
Net assets of non-consolidated VIEs	47	91
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Other current liabilities	97	98
Other liabilities	3,219	2,730
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	60	113
Total assets	60	113
Net assets of non-consolidated VIEs	$ 60	$ 113