Debt Obligations (Long-term Debt Maturities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014
Due within one year	$ 20.2
Due within two years	40.1
Due within three years	915.1
Due within four years	40.1
Due within five years	50.1
Thereafter	1,232.7
Total Maturities	2,298.3
Unamortized discounts and premiums, net	3.9
Total	2,294.4
DP&L [Member]
Due within one year	0.2
Due within two years	0.1
Due within three years	445.1
Due within four years	0.1
Due within five years	0.1
Thereafter	432.2
Total Maturities	877.8
Unamortized discounts and premiums, net	(0.7)
Total	$ 877.1