Employee Benefit Plans (Sensitivity to Changes in Assumed Health Care Cost Trend Rates) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	$ 2
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	36
Effect on total service and interest costs - 1 Percentage Point Decrease	(2)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(31)
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	9
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(8)
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	15
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(13)
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	8
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(7)
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	7
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(6)
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	2
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(1)
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	4
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	$ (3)

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Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (m)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

+ Details

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

+ Details

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

+ Details

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