Benefit Plans

The components of net periodic benefit cost for the three months ended June 30 were as follows ($ in millions):



	Pension benefits						Other retirement benefits						Total
	2016			2015			2016			2015			2016			2015
Service cost	$	2.7		$	2.7		$	0.1		$	0.2		$	2.8		$	2.9
Interest cost	2.6			3.9			0.1			0.1			2.7			4.0
Expected return on assets	(3.2		)	(5.7		)	—			—			(3.2		)	(5.7		)
Amortization of prior service credit	(0.3		)	(0.3		)	—			—			(0.3		)	(0.3		)
Recognized actuarial losses (gains)	1.1			1.6			(0.3		)	(0.4		)	0.8			1.2
Net periodic benefit cost	$	2.9		$	2.2		$	(0.1	)	$	(0.1	)	$	2.8		$	2.1

The components of net periodic benefit cost for the six months ended June 30 were as follows ($ in millions):



	Pension benefits						Other retirement benefits						Total
	2016			2015			2016			2015			2016			2015
Service cost	$	5.3		$	5.4		$	0.3		$	0.3		$	5.6		$	5.7
Interest cost	5.2			7.8			0.2			0.2			5.4			8.0
Expected return on assets	(6.3		)	(11.4		)	—			—			(6.3		)	(11.4		)
Amortization of prior service credit	(0.7		)	(0.6		)	—			—			(0.7		)	(0.6		)
Recognized actuarial losses (gains)	2.3			3.2			(0.7		)	(0.7		)	1.6			2.5
Net periodic benefit cost	$	5.8		$	4.4		$	(0.2	)	$	(0.2	)	$	5.6		$	4.2