Ownership of Coal-fired Facilities (Ownership Interests) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 MW
Construction Work in Process	$ 24.0
Beckjord Unit 6 [Member]
Ownership (%)	50.00%
Conesville Unit 4 [Member]
Production Capacity (MW)	129
Hutchings Station [Member]
Ownership (%)	100.00%
DP&L [Member]
Construction Work in Process	24.0
DP&L [Member] | Conesville Unit 4 [Member]
Production Capacity (MW)	129
DP&L [Member] | East Bend Station [Member]
Production Capacity (MW)	186
DP&L Share [Member] | Beckjord Unit 6 [Member]
Ownership (%)	50.00%
Production Capacity (MW)	207
DP&L Share [Member] | Conesville Unit 4 [Member]
Ownership (%)	16.50%
Production Capacity (MW)	129
DP&L Share [Member] | East Bend Station [Member]
Ownership (%)	31.00%
Production Capacity (MW)	186
DP&L Share [Member] | Killen Station [Member]
Ownership (%)	67.00%
Production Capacity (MW)	402
DP&L Share [Member] | Miami Fort Units 7 and 8 [Member]
Ownership (%)	36.00%
Production Capacity (MW)	368
DP&L Share [Member] | Stuart Station [Member]
Ownership (%)	35.00%
Production Capacity (MW)	808
DP&L Share [Member] | Zimmer Station [Member]
Ownership (%)	28.10%
Production Capacity (MW)	365
DP&L Share [Member] | Total Jointly-owned Stations [Member]
Production Capacity (MW)	2,465
DP&L Share [Member] | Hutchings Station [Member]
Ownership (%)	100.00%
DP&L Share [Member] | DP&L [Member] | Beckjord Unit 6 [Member]
Ownership (%)	50.00%
Production Capacity (MW)	207
DP&L Share [Member] | DP&L [Member] | Conesville Unit 4 [Member]
Ownership (%)	16.50%
Production Capacity (MW)	129
DP&L Share [Member] | DP&L [Member] | East Bend Station [Member]
Ownership (%)	31.00%
Production Capacity (MW)	186
DP&L Share [Member] | DP&L [Member] | Killen Station [Member]
Ownership (%)	67.00%
Production Capacity (MW)	402
DP&L Share [Member] | DP&L [Member] | Miami Fort Units 7 and 8 [Member]
Ownership (%)	36.00%
Production Capacity (MW)	368
DP&L Share [Member] | DP&L [Member] | Stuart Station [Member]
Ownership (%)	35.00%
Production Capacity (MW)	808
DP&L Share [Member] | DP&L [Member] | Zimmer Station [Member]
Ownership (%)	28.10%
Production Capacity (MW)	365
DP&L Share [Member] | DP&L [Member] | Total Jointly-owned Stations [Member]
Production Capacity (MW)	2,465
DP&L Share [Member] | DP&L [Member] | Hutchings Station [Member]
Ownership (%)	100.00%
DP&L Investment [Member] | Beckjord Unit 6 [Member]
Gross Plant In Service	2
Accumulated Depreciation	1
SCR and FGD Equipment Installed and In Service	No
DP&L Investment [Member] | Conesville Unit 4 [Member]
Gross Plant In Service	24
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | East Bend Station [Member]
Gross Plant In Service	12
Accumulated Depreciation	5
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | Killen Station [Member]
Gross Plant In Service	306
Accumulated Depreciation	9
Construction Work in Process	4.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | Miami Fort Units 7 and 8 [Member]
Gross Plant In Service	212
Accumulated Depreciation	13
Construction Work in Process	1.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | Stuart Station [Member]
Gross Plant In Service	205
Accumulated Depreciation	12
Construction Work in Process	16.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | Zimmer Station [Member]
Gross Plant In Service	177
Accumulated Depreciation	25
Construction Work in Process	3.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | Total Jointly-owned Stations [Member]
Gross Plant In Service	979
Accumulated Depreciation	69
Construction Work in Process	24.0
DP&L Investment [Member] | Transmission (At Varying Percentages) [Member]
Gross Plant In Service	41
Accumulated Depreciation	4
DP&L Investment [Member] | Hutchings Station [Member]
SCR and FGD Equipment Installed and In Service	No
DP&L Investment [Member] | DP&L [Member] | Beckjord Unit 6 [Member]
Gross Plant In Service	76
Accumulated Depreciation	69
SCR and FGD Equipment Installed and In Service	No
DP&L Investment [Member] | DP&L [Member] | Conesville Unit 4 [Member]
Gross Plant In Service	20
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | East Bend Station [Member]
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | Killen Station [Member]
Gross Plant In Service	622
Accumulated Depreciation	303
Construction Work in Process	4.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | Miami Fort Units 7 and 8 [Member]
Gross Plant In Service	361
Accumulated Depreciation	152
Construction Work in Process	1.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | Stuart Station [Member]
Gross Plant In Service	744
Accumulated Depreciation	307
Construction Work in Process	16.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | Zimmer Station [Member]
Gross Plant In Service	1,098
Accumulated Depreciation	657
Construction Work in Process	3.0
SCR and FGD Equipment Installed and In Service	Yes
DP&L Investment [Member] | DP&L [Member] | Total Jointly-owned Stations [Member]
Gross Plant In Service	3,019
Accumulated Depreciation	1,548
Construction Work in Process	24.0
DP&L Investment [Member] | DP&L [Member] | Transmission (At Varying Percentages) [Member]
Gross Plant In Service	98
Accumulated Depreciation	$ 60
DP&L Investment [Member] | DP&L [Member] | Hutchings Station [Member]
SCR and FGD Equipment Installed and In Service	No