Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 26	$ 351
Net amounts presented on Balance Sheets	26	110
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	419	909
Net amounts presented on Balance Sheets	419	668
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	18	210
Gross amounts offset	(3)	(153)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		57
Net amounts presented on Balance Sheets	15	57
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	136
Gross amounts offset	(4)	(88)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		48
Derivative Asset, Not Subject to Master Netting Arrangement		5
Net amounts presented on Balance Sheets	4	53
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	271	573
Gross amounts offset	(22)	(213)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		360
Derivative Liability, Not Subject to Master Netting Arrangement		1
Net amounts presented on Balance Sheets	249	361
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	148	319
Gross amounts offset	(16)	(173)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		146
Derivative Liability, Not Subject to Master Netting Arrangement		16
Net amounts presented on Balance Sheets	132	162
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	45	19
Net amounts presented on Balance Sheets	45	19
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	32	14
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		14
Net amounts presented on Balance Sheets	32	14
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	13	5
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		5
Net amounts presented on Balance Sheets	13	5
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	2
Net amounts presented on Balance Sheets	11	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	322	371
Net amounts presented on Balance Sheets	322	373
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	2
Gross amounts offset	(2)	(2)
Net amounts presented on Balance Sheets	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(4)
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	225	289
Gross amounts offset	(21)	(17)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		272
Net amounts presented on Balance Sheets	204	272
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	97	82
Gross amounts offset	(15)	(8)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		74
Net amounts presented on Balance Sheets	82	74
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts presented on Balance Sheets	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	98	132
Net amounts presented on Balance Sheets	98	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts presented on Balance Sheets	2
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	77	109
Gross amounts offset	(1)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		109
Net amounts presented on Balance Sheets	76	109
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	21	23
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		23
Net amounts presented on Balance Sheets	21	23
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	2
Net amounts presented on Balance Sheets	7	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	216	239
Net amounts presented on Balance Sheets	216	241
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	2
Gross amounts offset	(2)	(2)
Net amounts presented on Balance Sheets	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(4)
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	145	180
Gross amounts offset	(20)	(17)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		163
Net amounts presented on Balance Sheets	125	163
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	71	59
Gross amounts offset	(15)	(8)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		51
Net amounts presented on Balance Sheets	56	51
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	341
Net amounts presented on Balance Sheets	3	49
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	473
Net amounts presented on Balance Sheets	7	181
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	204
Gross amounts offset		(179)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		25
Net amounts presented on Balance Sheets	3	25
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		137
Gross amounts offset		(114)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		23
Net amounts presented on Balance Sheets		23
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	257
Gross amounts offset		(222)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		35
Net amounts presented on Balance Sheets	1	35
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	216
Gross amounts offset		(193)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		23
Net amounts presented on Balance Sheets	6	23
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	14
Net amounts presented on Balance Sheets	7	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	14
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		14
Net amounts presented on Balance Sheets	$ 7	$ 14