Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 613	$ 499
Investments and other assets	2,972	3,042
Other current liabilities	1,784	2,115
Deferred credits and other liabilities	32,869	32,490
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies		0
Investments in equity method unconsolidated affiliates	474	387
Total assets	474	387
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets	458	370
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies		0
Investments in equity method unconsolidated affiliates	222	235
Total assets	222	235
Net assets	222	235
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies		0
Investments in equity method unconsolidated affiliates	252	152
Total assets	252	152
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets	236	135
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	35	84
Investments and other assets	16	20
Other current liabilities	82	153
Deferred credits and other liabilities	2,054	1,998
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	39	47
Total assets	39	47
Net assets	39	47
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	60	71
Other current liabilities	101	97
Deferred credits and other liabilities	3,280	3,219
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	58	60
Total assets	58	60
Net assets	$ 58	$ 60