Variable Interest Entities (Consolidated VIEs) (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Restricted Receivables of VIEs	$ 1,152	$ 1,302
Other Current Assets	758	1,078
Intangibles, net	371	467
Restricted Other Assets of VIEs	176	139
Other Assets	2,236	2,300
Property, Plant and Equipment Cost, VIEs	921	942
Less Accumulated Depreciation and Amortization	(18,905)	(18,195)
Other Assets and Deferred Debits	2,479	2,233
Accounts payable	1,080	1,587
Non-Recourse Notes Payable	275	216
Taxes accrued	438	412
Current Maturities of Long-Term Debt	1,527	275
Other Current Liabilities	1,046	1,170
Non-Recourse Long-Term Debt	959	976
Deferred Income Taxes	7,466	6,978
Asset Retirement Obligation	1,905	1,816
Other Liabilities	5,430	5,452
Noncontrolling interests	105	131
Total common stockholder's equity	22,794	22,522
DERF [Member] | Consolidated VIEs [Member]
Restricted Receivables of VIEs	637	637
Total Assets	637	637
Non-Recourse Long-Term Debt	300	300
Total Liabilities	300	300
Total common stockholder's equity	337	337
Consolidated VIEs [Member]
Restricted Receivables of VIEs	1,152	1,302
Other Current Assets	94	294
Intangibles, net	12	13
Restricted Other Assets of VIEs	176	139
Other Assets	21	23
Property, Plant and Equipment Cost, VIEs	921	942
Less Accumulated Depreciation and Amortization	(53)	(55)
Other Assets and Deferred Debits	34	21
Total Assets	2,357	2,679
Accounts payable	3	4
Non-Recourse Notes Payable	275	216
Taxes accrued	3	1
Current Maturities of Long-Term Debt	72	61
Other Current Liabilities	62	21
Non-Recourse Long-Term Debt	959	976
Deferred Income Taxes	173	191
Asset Retirement Obligation	12	12
Other Liabilities	58	26
Total Liabilities	1,617	1,508
Noncontrolling interests	2	1
Total common stockholder's equity	738	1,170
Consolidated VIEs [Member] | Cinergy Receivables [Member]
Restricted Receivables of VIEs	492	629
Total Assets	492	629
Non-Recourse Notes Payable	275	216
Total Liabilities	275	216
Total common stockholder's equity	217	413
Consolidated VIEs [Member] | CinCap V [Member]
Restricted Receivables of VIEs	13	12
Other Current Assets	4	4
Restricted Other Assets of VIEs	67	76
Other Assets	21	23
Total Assets	105	115
Current Maturities of Long-Term Debt	10	9
Other Current Liabilities	5	5
Non-Recourse Long-Term Debt	63	71
Other Liabilities	20	22
Total Liabilities	98	107
Total common stockholder's equity	7	8
Consolidated VIEs [Member] | Renewables [Member]
Restricted Receivables of VIEs	7	20
Other Current Assets	82	282
Intangibles, net	12	13
Restricted Other Assets of VIEs	48	(2)
Property, Plant and Equipment Cost, VIEs	921	892
Less Accumulated Depreciation and Amortization	(53)	(26)
Other Assets and Deferred Debits	25	24
Total Assets	1,042	1,203
Accounts payable	1	2
Taxes accrued	3	1
Current Maturities of Long-Term Debt	57	45
Other Current Liabilities	57	16
Non-Recourse Long-Term Debt	533	518
Deferred Income Taxes	173	191
Asset Retirement Obligation	12	12
Other Liabilities	37	4
Total Liabilities	873	789
Total common stockholder's equity	169	414
Consolidated VIEs [Member] | Other VIEs [Member]
Restricted Receivables of VIEs	3	4
Other Current Assets	8	8
Restricted Other Assets of VIEs	61	65
Property, Plant and Equipment Cost, VIEs		50
Less Accumulated Depreciation and Amortization		(29)
Other Assets and Deferred Debits	9	(3)
Total Assets	81	95
Accounts payable	2	2
Current Maturities of Long-Term Debt	5	7
Non-Recourse Long-Term Debt	63	87
Other Liabilities	1
Total Liabilities	71	96
Noncontrolling interests	2	1
Total common stockholder's equity	8	(2)
Non-Consolidated VIEs [Member]
Intangibles, net	113	119
Other Current Liabilities	1	3
Total common stockholder's equity	333	343
Non-Consolidated VIEs [Member] | Renewables [Member]
Total common stockholder's equity	84	95
Non-Consolidated VIEs [Member] | Other VIEs [Member]
Intangibles, net	113	119
Other Current Liabilities	1	3
Total common stockholder's equity	$ 119	$ 111