Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 925	$ 499
Investments and other assets	2,752	2,830
Other current liabilities	2,044	2,011
Deferred credits and other liabilities	34,593	33,143
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	751	387
Investments and other assets	12
Total assets	763	387
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets of non-consolidated VIEs	747	370
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	487	113
Investments and other assets	12
Total assets	499	113
Net assets of non-consolidated VIEs	499	113
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	174	235
Total assets	174	235
Net assets of non-consolidated VIEs	174	235
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	90	39
Total assets	90	39
Other current liabilities	3	3
Deferred credits and other liabilities	13	14
Total liabilities	16	17
Net assets of non-consolidated VIEs	74	22
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	129	84
Investments and other assets	21	20
Other current liabilities	91	153
Deferred credits and other liabilities	1,978	1,998
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	82	47
Investments in equity method unconsolidated affiliates
Total assets	82	47
Net assets of non-consolidated VIEs	82	47
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	114	71
Other current liabilities	93	97
Deferred credits and other liabilities	3,749	3,219
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables from affiliated companies	101	60
Total assets	101	60
Net assets of non-consolidated VIEs	$ 101	$ 60