Income Taxes (Other Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	$ 88	$ 213	$ 230
Gross decreases-tax positions in prior periods	(4)	(48)	(2)
Decreases due to settlements	(68)	(45)	(15)
Reduction due to lapse of statute of limitations	1	(32)
Total changes	(71)	(125)	(17)
Unrecognized Tax Benefits - December 31	17	88	213
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	8
Amount that if recognized, would affect the effective tax rate or regulatory liability	8
Amount that if recognized, would be recorded as a component of discontinued operations	5
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		12	6
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest receivable related to income taxes		3
Interest payable related to income taxes	4		13
Duke Energy Carolinas [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	72	160	171
Gross decreases-tax positions in prior periods	(4)	(45)
Decreases due to settlements	(67)	(43)	(11)
Total changes	(71)	(88)	(11)
Unrecognized Tax Benefits - December 31	1	72	160
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	1
Amount that if recognized, would affect the effective tax rate or regulatory liability	1
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest expense recognized related to income taxes	7	1	1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	23	14	13
Progress Energy [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	1	32	32
Gross increases-tax positions in prior periods		1	1
Gross decreases-tax positions in prior periods	(1)
Decreases due to settlements			(1)
Reduction due to lapse of statute of limitations	2	(32)
Total changes	1	(31)
Unrecognized Tax Benefits - December 31	2	1	32
Amount that if recognized, would affect the effective tax rate or regulatory liability	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	1	2	3
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	1		5
Duke Energy Progress [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	3	23	22
Gross increases-tax positions in prior periods		1	1
Gross decreases-tax positions in prior periods	(1)
Reduction due to lapse of statute of limitations		(21)
Total changes	(1)	(20)	1
Unrecognized Tax Benefits - December 31	2	3	23
Amount that if recognized, would affect the effective tax rate or regulatory liability	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		2
Net interest expense recognized related to income taxes			1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes	1	1	3
Duke Energy Florida [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1		8	8
Reduction due to lapse of statute of limitations		(8)
Total changes		(8)
Unrecognized Tax Benefits - December 31			8
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes	2	1	1
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest payable related to income taxes			5
Duke Energy Ohio [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross increases-tax positions in prior periods	4
Total changes	4
Unrecognized Tax Benefits - December 31	4
Amount that if recognized, would be recorded as a component of discontinued operations	2
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes			4
Duke Energy Indiana [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	1	1	1
Decreases due to settlements	(1)
Total changes	$ (1)
Unrecognized Tax Benefits - December 31		1	1
Income Tax Examination, Penalties and Interest Expense [Abstract]
Net interest income recognized related to income taxes		1	4
Income Tax Examination, Penalties and Interest Accrued [Abstract]
Interest receivable related to income taxes		$ 3	$ 2