Employee Benefit Plans (Projected Benefit Obligations Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	$ 17	$ 9		$ (23)
Net amount recognized in accumulated other comprehensive (income) loss	(38)	(19)		49
Progress Energy [Member]
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)				27
Net amount recognized in accumulated other comprehensive (income) loss	(9)	2		(39)	[1]
Duke Energy Ohio [Member]
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(8)
Net amount recognized in accumulated other comprehensive (income) loss	(1)	(27)	[2]	6
Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(788)	976
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	18	14
Actuarial (gains) losses arising during the year	(33)	(2)
Prior year service cost (credit) arising during the year	(1)	(7)
Amortization of prior year actuarial gains (losses)	(15)	(13)
Reclassification of actuarial gains (losses) to regulatory assets	3	(20)
Amortization of prior year service cost		(1)
Net amount recognized in accumulated other comprehensive (income) loss	(28)	(29)
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(205)	(111)
Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(253)	(76)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Actuarial (gains) losses arising during the year	(2)	3
Amortization of prior year actuarial gains (losses)	(3)	(2)
Amortization of prior year service cost		(1)
Net amount recognized in accumulated other comprehensive (income) loss	(5)	0
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(109)	(89)
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(146)	23
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(96)	22
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		15
Reclassification of actuarial losses to an affiliate		(48)
Amortization of prior year actuarial gains (losses)		(3)
Reclassification of actuarial gains (losses) to regulatory assets		(1)
Amortization of prior year service cost		(1)
Net amount recognized in accumulated other comprehensive (income) loss	0	(38)
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(99)	17
Non Qualified Pension Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(14)	34
Regulatory liabilities, net increase (decrease)	5	(8)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Actuarial (gains) losses arising during the year	2	(2)
Prior year service cost (credit) arising during the year	(1)
Net amount recognized in accumulated other comprehensive (income) loss	1	(2)
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	1
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(16)	(6)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	1	(1)
Actuarial (gains) losses arising during the year	(5)	3
Net amount recognized in accumulated other comprehensive (income) loss	(4)	2
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(4)	(2)
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(3)	1
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(2)
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(683)	484
Regulatory liabilities, net increase (decrease)	30	(6)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)	2	(2)
Actuarial (gains) losses arising during the year	(4)
Prior year service cost (credit) arising during the year	(3)
Amortization of prior year actuarial gains (losses)	1
Reclassification of actuarial gains (losses) to regulatory liabilities		4
Net amount recognized in accumulated other comprehensive (income) loss	(4)	2
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(51)	(20)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(634)	228
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(388)	170
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(166)	28
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)	3	(1)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax benefit (expense)		(4)
Reclassification of actuarial losses to an affiliate		6
Actuarial (gains) losses arising during the year		2
Prior year service cost (credit) arising during the year		1
Amortization of prior year actuarial gains (losses)		1
Net amount recognized in accumulated other comprehensive (income) loss	0	6
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	(6)	(6)
Regulatory liabilities, net increase (decrease)	$ 9	$ (2)

[1] Net of $27 million tax expense in 2011.

[2] Net of $8 million tax expense in 2012.