Contractual Obligations, Commercial Commitments And Contingencies (Schedule Of Contractual Obligations And Commercial Commitments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total long-term debt	$ 2,598.7
Long-term debt, Less than 1 year	570.4
Long-term debt, 2 - 3 years	425.3
Long-term debt, 4 - 5 years	450.2
Long-term debt, More than 5 years	1,152.8
Total Interest payments	1,031.4
Interest payments, Less than 1 year	133.5
Interest payments, 2 - 3 years	216.3
Interest payments, 4 - 5 years	174.1
Interest payments, More than 5 years	507.5
Total Pension and postretirement payments	256.2
Pension and postretirement payments, Less than 1 year	24.6
Pension and postretirement payments, 2 - 3 years	50.3
Pension and postretirement payments, 4 - 5 years	51.1
Pension and postretirement payments, More than 5 years	130.2
Total Operating leases	1.0
Operating leases, Less than 1 year	0.4
Operating leases, 2 - 3 years	0.6
Total Coal Contracts	586.4
Coal Contracts, Less than 1 year	227.6
Coal Contracts, 2 - 3 years	150.6
Coal Contracts, 4 - 5 years	138.8
Coal Contracts, More than 5 years	69.4
Total Limestone Contracts	26.8
Limestone Contracts, Less than 1 year	5.4
Limestone Contracts, 2 - 3 years	10.7
Limestion Contracts, 4 - 5 years	10.7
Total Purchase orders and other contractual obligations	55.9
Purchase orders and other contractual obligations, Less than 1 year	34.6
Purchase orders and other contractual obligations, 2 - 3 years	10.9
Purchase orders and other contractual obligations, 4 - 5 years	10.4
Total Reserve for uncertain tax positions	18.3
Reserve for uncertain tax positions, less than 1 year	18.3
Total contractual obligations	4,574.7
Total contractual obligations, Less than 1 year	1,014.8
Total contractual obligations, 2 - 3 years	864.7
Total contractual obligations, 4 - 5 years	835.3
Total contractual obligations, More than 5 years	1,859.9
DP&L [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total long-term debt	903.2
Long-term debt, Less than 1 year	570.4
Long-term debt, 2 - 3 years	0.3
Long-term debt, 4 - 5 years	0.2
Long-term debt, More than 5 years	332.3
Total Interest payments	361.9
Interest payments, Less than 1 year	34.0
Interest payments, 2 - 3 years	31.6
Interest payments, 4 - 5 years	31.6
Interest payments, More than 5 years	264.7
Total Pension and postretirement payments	256.2
Pension and postretirement payments, Less than 1 year	24.6
Pension and postretirement payments, 2 - 3 years	50.3
Pension and postretirement payments, 4 - 5 years	51.1
Pension and postretirement payments, More than 5 years	130.2
Total Operating leases	1.0
Operating leases, Less than 1 year	0.4
Operating leases, 2 - 3 years	0.6
Total Coal Contracts	586.4
Coal Contracts, Less than 1 year	227.6
Coal Contracts, 2 - 3 years	150.6
Coal Contracts, 4 - 5 years	138.8
Coal Contracts, More than 5 years	69.4
Total Limestone Contracts	26.8
Limestone Contracts, Less than 1 year	5.4
Limestone Contracts, 2 - 3 years	10.7
Limestion Contracts, 4 - 5 years	10.7
Total Purchase orders and other contractual obligations	55.9
Purchase orders and other contractual obligations, Less than 1 year	34.6
Purchase orders and other contractual obligations, 2 - 3 years	10.9
Purchase orders and other contractual obligations, 4 - 5 years	10.4
Total Reserve for uncertain tax positions	18.3
Reserve for uncertain tax positions, less than 1 year	18.3
Total contractual obligations	2,209.7
Total contractual obligations, Less than 1 year	915.3
Total contractual obligations, 2 - 3 years	255.0
Total contractual obligations, 4 - 5 years	242.8
Total contractual obligations, More than 5 years	$ 796.6