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The after tax amount of amortization of prior year actuarial gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise.

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No definition available.

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The increase (decrease) during the reporting period in the value of other assets that are created when regulatory agencies permits public utilities to defer costs to the balance sheet.

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The increase (decrease) during the reporting period in regulated liabilities. Regulated liabilities are created when regulatory agency permits an entity to defer revenues to the balance sheet.

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Amount, before tax, of cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount, after tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2016
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss		$ 6	$ (3)	$ 11
Progress Energy [Member]
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Net amount recognized in accumulated other comprehensive (income) loss		(5)	(4)	$ (1)
Pension Plan [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		298	(212)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		(2)
Prior year service cost (credit) arising during the year		1	1
Amortization of prior year actuarial gains (losses)		10	(7)
Net amount recognized in accumulated other comprehensive (income) loss		9	(6)
Pension Plan [Member] \| Nonqualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(16)	5
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		1
Actuarial (gains) losses arising during the year		(4)	2
Prior year service cost (credit) arising during the year			(1)
Net amount recognized in accumulated other comprehensive (income) loss		(3)	1
Pension Plan [Member] \| Duke Energy Carolinas [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		170	(70)
Pension Plan [Member] \| Duke Energy Carolinas [Member] \| Nonqualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		1	(1)
Pension Plan [Member] \| Progress Energy [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		40	(49)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		1	3
Amortization of prior year actuarial gains (losses)		(4)	(7)
Net amount recognized in accumulated other comprehensive (income) loss		(3)	(4)
Pension Plan [Member] \| Progress Energy [Member] \| Nonqualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(6)	3
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		1
Actuarial (gains) losses arising during the year		(3)
Net amount recognized in accumulated other comprehensive (income) loss		(2)
Pension Plan [Member] \| Duke Energy Progress [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		31	(37)
Pension Plan [Member] \| Duke Energy Progress [Member] \| Nonqualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(3)	1
Pension Plan [Member] \| Duke Energy Florida [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		9	(11)
Pension Plan [Member] \| Duke Energy Florida [Member] \| Nonqualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(3)	2
Pension Plan [Member] \| Duke Energy Ohio [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		10	9
Pension Plan [Member] \| Duke Energy Indiana [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		30	(19)
Pension Plan [Member] \| Piedmont Natural Gas [Member] \| Qualified Plan [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	$ 34	8	(64)		$ 35
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)			0
Prior year service cost (credit) arising during the year			0
Amortization of prior year actuarial gains (losses)			0
Net amount recognized in accumulated other comprehensive (income) loss			0
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		137	71
Regulatory liabilities, net increase (decrease)		154	(27)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)		(1)	(1)
Amortization of prior year prior service cost		1	3
Net amount recognized in accumulated other comprehensive (income) loss			2
Other Post-Retirement Benefit Plans [Member] \| Duke Energy Carolinas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)		(6)	(2)
Other Post-Retirement Benefit Plans [Member] \| Progress Energy [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		133	81
Regulatory liabilities, net increase (decrease)		149
Other Post-Retirement Benefit Plans [Member] \| Duke Energy Progress [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		84	42
Regulatory liabilities, net increase (decrease)		93
Other Post-Retirement Benefit Plans [Member] \| Duke Energy Florida [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		49	39
Regulatory liabilities, net increase (decrease)		56
Other Post-Retirement Benefit Plans [Member] \| Duke Energy Ohio [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory liabilities, net increase (decrease)		2	(3)
Other Post-Retirement Benefit Plans [Member] \| Duke Energy Indiana [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)		(5)	(5)
Regulatory liabilities, net increase (decrease)		3	(7)
Other Post-Retirement Benefit Plans [Member] \| Piedmont Natural Gas [Member]
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]
Regulatory assets, net increase (decrease)	$ (1)	$ 4	(11)		$ 2
Regulatory liabilities, net increase (decrease)			0
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]
Deferred income tax expense (benefit)			0
Amortization of prior year prior service cost			0
Net amount recognized in accumulated other comprehensive (income) loss			$ 0