Condensed Consolidated Statement of Operations (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension and OPEB related adjustments to AOCI, tax	$ (10)	$ 0	$ (7)	$ (3)
Net unrealized gains (losses) on cash flow hedges, tax	(1)	(26)	(10)	(28)
Reclassification into earnings from cash flow hedges, tax	0	0	0	1
Duke Energy Carolinas [Member]
Reclassification into earnings from cash flow hedges, tax	0	(1)	2	1
Duke Energy Ohio [Member]
Pension and OPEB related adjustments to AOCI, tax	0	(1)	1	0
Duke Energy Indiana [Member]
Reclassification into earnings from cash flow hedges, tax		$ (1)		$ (1)

Tax effects of the increase (decrease) to accumulated comprehensive income during the period related to benefit plans. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

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Total tax effect of the change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. The change includes an entity's share of an equity investee's increase or decrease in deferred hedging gains or losses. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

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- Definition

Tax effect on reclassification adjustment for accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

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