Commitments And Contingencies (Future Minimum Payments For Operating And Capital Leases) (Details) (Duke Energy Corp [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Duke Energy Corp [Member]
Operating Leases, Future Minimum Payments Due [Abstract]
2012	$ 81
2013	70
2014	55
2015	42
2016	31
Thereafter	202
Total future minimum lease payments	481
Capital Leases, Future Minimum Payments Due [Abstract]
2012	36
2013	25
2014	23
2015	22
2016	24
Thereafter	176
Total future minimum lease payments	$ 306

The total of contractually required rental payments on leases meeting the criteria for capitalization.

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Contractually required rental payments on leases meeting the criteria for capitalization, due within one year of the balance sheet date.

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The total of future contractually required payments on leases defined as operating.

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