Merger Agreement (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			6 Months Ended	9 Months Ended					3 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Jun. 30, 2012	Sep. 30, 2012		Sep. 30, 2011	Jul. 02, 2012	Dec. 31, 2011	Sep. 30, 2012 Other Duke Subsidiaries [Member]	Sep. 30, 2012 Other Duke Subsidiaries [Member]	Sep. 30, 2012 Other Duke Subsidiaries [Member]	Sep. 30, 2012 PEC [Member]	Sep. 30, 2011 PEC [Member]	Sep. 30, 2012 PEC [Member]	Sep. 30, 2011 PEC [Member]	Sep. 30, 2012 PEC [Member]	Sep. 30, 2012 PEF [Member]	Sep. 30, 2011 PEF [Member]	Sep. 30, 2012 PEF [Member]	Sep. 30, 2011 PEF [Member]	Sep. 30, 2012 PEF [Member]
Discontinued operations attributable to controlling interests
Income (loss) from discontinued operations, net of tax	$ 3		$ 0		$ 10		$ (4)
Discontinued operations, pre-tax gain from indemnification reversals					18
Merger Agreement [Line Items]
Merger Share Exchange Ratio, Adjusted								0.87083
Settlement agreement, fuel savings	650				650
Interim FERC Mitigation Rate Reduction					65
Community support and charitable contributions					99
FERC Mitigation					71										71
Severance Charges	66				66								42		42			24		24
Community support, charitable contributions and other					63										54					9
Total charges recognized					200										167					33
Cost to achieve the merger, pre-tax	218		14		241		32						180	7	194	17		38	7	47	15
Estimated exit cost liability	17				17
Exit cost liability recognized	2	[1]		5	7					1	1	1	1		4		8	0		2		3
Estimated exit cost liability expense allocation											4				9					4
Exit cost liability	$ 12	[2]		$ 10	$ 12	[2]			$ 5

[1] PEC, PEF and other Duke Energy subsidiaries recognized exit costs of $1 million, $- million and $1 million, respectively, for the three months ended September 30, 2012, and $4 million, $2 million and $1 million, respectively, for the nine months ended September 30, 2012.

[2] Expense related to the recognition of the cumulative exit cost liability at September 30, 2012, was attributed to PEC, PEF and other Duke Energy subsidiaries totaling $8 million, $3 million and $1 million, respectively.