Property, Plant and Equipment (Ownership of Coal-Fired Facilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 MW
Jointly Owned Utility Plant Interests [Line Items]
Production Capacity (MW)	2,465
Beckjord Unit 6
Jointly Owned Utility Plant Interests [Line Items]
Ownership	50.00%
Production Capacity (MW)	207
Gross Plant In Service	$ 2
Accumulated Depreciation	1
Construction Work In Process	0
Conesville Unit 4
Jointly Owned Utility Plant Interests [Line Items]
Ownership	17.00%
Production Capacity (MW)	129
Gross Plant In Service	24
Accumulated Depreciation	0
Construction Work In Process	0
East Bend Station
Jointly Owned Utility Plant Interests [Line Items]
Ownership	31.00%
Production Capacity (MW)	186
Gross Plant In Service	12
Accumulated Depreciation	5
Construction Work In Process	0
Killen Station
Jointly Owned Utility Plant Interests [Line Items]
Ownership	67.00%
Production Capacity (MW)	402
Gross Plant In Service	306
Accumulated Depreciation	9
Construction Work In Process	4
Miami Fort Units 7 and 8
Jointly Owned Utility Plant Interests [Line Items]
Ownership	36.00%
Production Capacity (MW)	368
Gross Plant In Service	212
Accumulated Depreciation	13
Construction Work In Process	1
Stuart Station
Jointly Owned Utility Plant Interests [Line Items]
Ownership	35.00%
Production Capacity (MW)	808
Gross Plant In Service	205
Accumulated Depreciation	12
Construction Work In Process	16
Zimmer Station
Jointly Owned Utility Plant Interests [Line Items]
Ownership	28.00%
Production Capacity (MW)	365
Gross Plant In Service	177
Accumulated Depreciation	25
Construction Work In Process	3
Transmission
Jointly Owned Utility Plant Interests [Line Items]
Gross Plant In Service	41
Accumulated Depreciation	4
Construction Work In Process	0
Total Jointly Owned Plant
Jointly Owned Utility Plant Interests [Line Items]
Gross Plant In Service	979
Accumulated Depreciation	69
Construction Work In Process	$ 24