Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss	$ 11	$ 13	$ (4)
Progress Energy [Member]
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss	(1)	10	$ (9)
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	53	1
Regulatory liabilities, net increase (decrease)	(114)	(92)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	(2)	2
Actuarial (gains) losses arising during the year	3	(5)
Prior year service cost (credit) arising during the year		(3)
Amortization of Prior Year Prior Service Credit	1	3
Net amount recognized in accumulated other comprehensive (income) loss	2	(3)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)	(22)	(8)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	47	1
Regulatory liabilities, net increase (decrease)	(51)	(71)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(1)
Actuarial (gains) losses arising during the year		2
Amortization of Prior Year Prior Service Credit	1	(1)
Net amount recognized in accumulated other comprehensive (income) loss	1
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	38
Regulatory liabilities, net increase (decrease)	(25)	(36)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	9	1
Regulatory liabilities, net increase (decrease)	(26)	(35)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)	(2)	2
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(6)	(7)
Regulatory liabilities, net increase (decrease)	(12)	(8)
Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	214	173
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	4	6
Actuarial (gains) losses arising during the year		4
Prior year service cost (credit) arising during the year	(2)	1
Amortization of prior year actuarial gains (losses)	(7)	(11)
Defined Benefit Plan Amounts Transferred with Midwest Generation Disposal Group		3
Reclassification of actuarial gains (losses) to regulatory assets		(6)
Net amount recognized in accumulated other comprehensive (income) loss	(5)	(3)
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	4	65
Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	34	18
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		5
Amortization of prior year actuarial gains (losses)	(1)	(4)
Net amount recognized in accumulated other comprehensive (income) loss	(1)	1
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	18	14
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	16	4
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	2	14
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	9	11
Non Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(3)	(13)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(7)
Actuarial (gains) losses arising during the year	1	17
Prior year service cost (credit) arising during the year	(1)	1
Net amount recognized in accumulated other comprehensive (income) loss		11
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(2)	2
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	2	(16)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(5)
Actuarial (gains) losses arising during the year		13
Net amount recognized in accumulated other comprehensive (income) loss		8
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	1	(1)
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	1	(15)
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	$ (1)	$ (1)