Commitments, Environmental, Legal (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013 T	Mar. 01, 2011
Public Utility, Property, Plant and Equipment [Line Items]
Third party guarantees	$ 18,000,000
Due to third parties, current	700,000
Debt instrument interest percentage		4.20%
Environmental reserves	2,200,000
Percentage of energy generated by coal	97.00%
Annual CO2 emissions generation at stations, in tons	14,000,000
Supplemental Eviromental Project	200,000
Number of Auxiliary Boilers	7
Relief and civil penalties, per day	27,500
DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Equity ownership interest	4.90%
Long Term Debt Date Range Equity Ownership, Start	2018
Long Term Debt Date Range Equity Ownership, End	2040
Environmental reserves	2,200,000
Percentage of energy generated by coal	97.00%
Supplemental Eviromental Project	200,000
Number of tons of CO2 emitted per year including electric generating units	14,000,000
Number of Auxiliary Boilers	7
Relief and civil penalties, per day	27,500
Coal supply failure by suppliers	570,000
Electric Generation Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt obligation	1,569,800,000
DPLE and DPLER [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Third party guarantees	17,800,000
MC Squared [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Third party guarantees	200,000
Beckjord Unit 6 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Percentage of coal-fire power plant holdings	50.00%
Hutchings Plant [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Percentage of coal-fire power plant holdings	100.00%
Coal Supply Agreements [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Coal supply failure by suppliers	1,500,000
Coal Supply Agreements [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Coal supply failure by suppliers	1,500,000
Coal supply agreement, in tons	570,000
Debt Obligation on 4.9% Equity Ownership [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Equity ownership interest	4.90%
Equity ownership interest aggregate cost	76,900,000
Long Term Debt Date Range Equity Ownership, Start	2018
Long Term Debt Date Range Equity Ownership, End	2040
Debt Obligation on 4.9% Equity Ownership [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Equity ownership interest aggregate cost	$ 76,900,000
First Mortgage Bonds Maturing in October 2013 - 5.125% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	5.125%
First Mortgage Bonds Maturing in October 2013 - 5.125% [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	5.125%
Pollution Control Series Maturing in January 2028 - 4.70% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.70%
Pollution Control Series Maturing in January 2028 - 4.70% [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.70%
Pollution Control Series Maturing in January 2034 - 4.80% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.80%
Pollution Control Series Maturing in January 2034 - 4.80% [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.80%
Pollution Control Series Maturing in September 2036 - 4.80% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.80%
Pollution Control Series Maturing in September 2036 - 4.80% [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.80%
U.S. Government note maturing in February 2061 - 4.20% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.20%
U.S. Government note maturing in February 2061 - 4.20% [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	4.20%	4.20%
Note to DPL Capital Trust II Maturing in September 2031 - 8.125% [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	8.125%
Five Year Senior Unsecured Notes at 6.50% maturing on October 15, 2016 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	6.50%
Ten Year Senior Unsecured Notes at 7.25% maturing at October 15, 2021 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt instrument interest percentage	7.25%
NOx [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Emission Reductions	54.00%
NOx [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Emission Reductions	54.00%
SO2 [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Emission Reductions	73.00%
SO2 [Member] | DP&L [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Emission Reductions	73.00%