Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2019

Entity Information [Line Items]

Schedule of Net Periodic Benefit Cost / (Income)

The net periodic benefit cost of the pension benefit plans for the three and nine months ended September 30, 2019 and 2018 was:

	Three months ended						Nine months ended
	September 30,						September 30,
$ in millions	2019			2018			2019			2018
Service cost	$	0.9		$	1.5		$	2.7		$	4.5
Interest cost	3.7			3.4			11.2			10.3
Expected return on plan assets	(5.0		)	(5.3		)	(15.0		)	(15.9		)
Amortization of unrecognized:
Prior service cost	0.3			0.3			0.9			0.8
Actuarial loss	1.1			1.6			3.2			4.8
Net periodic benefit cost	$	1.0		$	1.5		$	3.0		$	4.5

THE DAYTON POWER AND LIGHT COMPANY [Member]

Entity Information [Line Items]

Schedule of Net Periodic Benefit Cost / (Income)

The net periodic benefit cost of the pension benefit plans for the three and nine months ended September 30, 2019 and 2018 was:

	Three months ended						Nine months ended
	September 30,						September 30,
$ in millions	2019			2018			2019			2018
Service cost	$	0.9		$	1.5		$	2.7		$	4.5
Interest cost	3.7			3.4			11.2			10.3
Expected return on plan assets	(5.0		)	(5.3		)	(15.0		)	(15.9		)
Amortization of unrecognized:
Prior service cost	0.4			0.4			1.3			1.1
Actuarial loss	1.8			2.4			5.3			7.1
Net periodic benefit cost	$	1.8		$	2.4		$	5.5		$	7.1