Variable Interest Entities (Schedule Of Non-Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Investments in equity method unconsolidated affiliates	$ 460	$ 444
Intangibles	363	467
Other Current Liabilities	1,091	1,370
Deferred Credits and Other Liabilities	15,454	14,605
Total common stockholder's equity	22,772	22,522
Duke Energy Ohio [Member]
Intangibles	143	248
Other Current Liabilities	122	135
Deferred Credits and Other Liabilities	2,490	2,255
Total common stockholder's equity	5,167	5,464	5,898	6,670
Duke Energy Indiana [Member]
Intangibles	50	64
Other Current Liabilities	93	110
Deferred Credits and Other Liabilities	2,079	2,087
Total common stockholder's equity	3,734	3,567	2,934	2,594
Non-Consolidated VIEs [Member]
Receivables
Investments in equity method unconsolidated affiliates	235	255
Intangibles	111	119
Total Assets	346	374
Other Current Liabilities	3	3
Deferred Credits and Other Liabilities	18	28
Total Liabilities	21	31
Total common stockholder's equity	325	343
Non-Consolidated VIEs [Member] | DukeNet [Member]
Receivables
Investments in equity method unconsolidated affiliates	129	137
Intangibles
Total Assets	129	137
Other Current Liabilities
Deferred Credits and Other Liabilities
Total Liabilities
Total common stockholder's equity	129	137
Non-Consolidated VIEs [Member] | Renewables [Member]
Receivables
Investments in equity method unconsolidated affiliates	81	95
Intangibles
Total Assets	81	95
Other Current Liabilities
Deferred Credits and Other Liabilities
Total Liabilities
Total common stockholder's equity	81	95
Non-Consolidated VIEs [Member] | Other VIEs [Member]
Receivables
Investments in equity method unconsolidated affiliates	25	23
Intangibles	111	119
Total Assets	136	142
Other Current Liabilities	3	3
Deferred Credits and Other Liabilities	18	28
Total Liabilities	21	31
Total common stockholder's equity	115	111
Non-Consolidated VIEs [Member] | Duke Energy Ohio [Member]
Receivables	129	216
Investments in equity method unconsolidated affiliates
Intangibles	111	119
Total Assets	240	335
Other Current Liabilities
Deferred Credits and Other Liabilities
Total Liabilities
Total common stockholder's equity	240	335
Non-Consolidated VIEs [Member] | Duke Energy Indiana [Member]
Receivables	139	192
Investments in equity method unconsolidated affiliates
Intangibles
Total Assets	139	192
Other Current Liabilities
Deferred Credits and Other Liabilities
Total Liabilities
Total common stockholder's equity	$ 139	$ 192