We maintain qualified and nonqualified defined benefit retirement plans covering certain current and former U.S. and European employees, retirement savings plans covering eligible U.S. and U.K. employees and certain postretirement health care and life insurance benefit plans covering eligible U.S. retirees. We also participate in a union sponsored multi-employer pension plan covering certain U.S. employees with union affiliations.

Net periodic benefit costs of our defined benefit retirement plans for the three and nine months ended September 30, 2019 and 2018 were as follows:

	Quarter Ended September 30,				Nine Months Ended September 30,
(In millions)	2019		2018		2019		2018
U.S. Nonqualified Defined Benefit Retirement Plans
Service cost	$	0.3	$	0.2	$	0.9	$	0.8
Interest cost		0.2		0.1		0.5		0.4
Net amortization	—			0.1	—			0.1
Net periodic benefit cost	$	0.5	$	0.4	$	1.4	$	1.3

(In millions)	September 30, 2019		December 31, 2018
Amounts recognized on the balance sheet for U.S. nonqualified defined benefit retirement plans:
Accrued liabilities	$	0.9	$	0.9
Other non-current liabilities		18.0		17.2
	$	18.9	$	18.1

	Quarter Ended September 30,						Nine Months Ended September 30,
(In millions)	2019			2018			2019			2018
European Defined Benefit Retirement Plans
Service cost	$	0.3		$	0.3		$	0.8		$	0.8
Interest cost		1.1			1.2			3.3			3.4
Expected return on plan assets		(2.1	)		(2.4	)		(6.5	)		(7.1	)
Net amortization and deferral	—			—				0.2			0.2
Net periodic benefit credit	$	(0.7	)	$	(0.9	)	$	(2.2	)	$	(2.7	)

(In millions)	September 30, 2019		December 31, 2018
Amounts recognized on the balance sheet for European defined benefit retirement plans:
Other assets	$	47.1	$	42.6

Accrued liabilities		0.3		0.4
Other non-current liabilities		18.1		18.8
Total accrued benefit	$	18.4	$	19.2

All costs related to our pensions are included as a component of operating income in our Condensed Consolidated Statements of Operations. For the three month periods ended September 30, 2019 and 2018, amounts unrelated to service costs were a benefit of $0.8 million and $1.0 million, respectively. For the nine months ended September 30, 2019 and 2018, amounts unrelated to the service costs were a benefit of $2.5 million and $3.0 million, respectively.

We generally fund our U.S. non-qualified defined benefit retirement plans when benefit payments are incurred. We have contributed approximately $0.5 million in the first nine months of 2019 to cover unfunded benefits. We expect to contribute a total of $0.9 million in 2019 to cover unfunded benefits. We contributed $4.4 million to our U.S. non-qualified defined benefit retirement plans during the first nine months of 2018.

We contributed $3.3 million and $3.8 million to our European defined benefit retirement plans during the nine months ended September 30, 2019 and 2018, respectively. We plan to contribute approximately $5.0 million during 2019 to our European plans.

We recorded $0.2 million of net amortization gain deferral for the quarter ended September 30, 2019 and $0.7 million and $0.9 million for the nine months ended September 30, 2019 and 2018, respectively. There were no amounts related to the amortization gain deferral recorded during the three months ended September 30, 2018. Net periodic benefit costs of our postretirement health care and life insurance benefit plans for the quarter and the nine months ended September 30, 2019 and 2018 were immaterial.

(In millions)	September 30, 2019		December 31, 2018
Amounts recognized on the balance sheet:
Accrued liabilities	$	0.5	$	0.5
Other non-current liabilities	2.7		2.8
Total accrued benefit	$	3.2	$	3.3

Amounts contributed in connection with our postretirement plans were immaterial for both the nine months ended September 30, 2019 and September 30, 2018. We periodically fund our postretirement plans to pay covered expenses as they are incurred. We expect to contribute less than $0.5 million in 2019 to cover unfunded benefits.