Property, Plant and Equipment (Tables)

3 Months Ended

Mar. 31, 2018

Property, Plant and Equipment [Line Items]

Schedule of Jointly Owned Utility Plants [Table Text Block]

DPL's undivided ownership interest in such facilities at March 31, 2018, was as follows:

	DPL Share		DPL Carrying Value
	Ownership (%)	Summer Production Capacity (MW)	Gross Plant In Service ($ in millions)		Accumulated Depreciation ($ in millions)		Construction Work in Process ($ in millions)
Jointly-owned production units
Conesville - Unit 4	16.5	129	$	0.6	$	0.6	$	2.3
Killen - Unit 2	67.0	402	9.5		9.1		—
Stuart - Units 2 through 4	35.0	606	1.8		1.8		—
Transmission (at varying percentages)			39.4		9.0		—
Total		1,137	$	51.3	$	20.5	$	2.3

Each of the above generating units has SCR and FGD equipment installed.

Schedule of Change in Asset Retirement Obligation [Table Text Block]

Changes in the Liability for AROs

$ in millions
Balance at January 1, 2018	$	131.2
Accretion expense	0.7
Settlements	(0.2		)
Reductions due to plant sales	(3.4		)
Balance at March 31, 2018	$	128.3

See Note 5 – Fair Value for further discussion on changes to our AROs.

Subsidiaries [Member]

Property, Plant and Equipment [Line Items]

Schedule of Change in Asset Retirement Obligation [Table Text Block]

Changes in the Liability for AROs

$ in millions
Balance at January 1, 2018	$	8.0
Revisions to cash flow and timing estimates	0.1
Reductions due to plant sales	(3.4		)
Balance at March 31, 2018	$	4.7