Postretirement and Other Benefits (Tables)

12 Months Ended

Dec. 31, 2017

Defined Benefit Plan Disclosure [Line Items]

The funded status of these plans as of December 31, 2017 and 2016 was as follows ($ in millions):



	Pension Benefits												OPEB Benefits
	United States						France						United States
	2017			2016			2017			2016			2017			2016
Change in Projected Benefit Obligation, or PBO:
PBO at beginning of year	$	123.2		$	123.4		$	32.4		$	32.2		$	1.4		$	1.7
Service cost	—			—			1.1			1.0			—			—
Interest cost	4.8			5.2			0.4			0.4			0.1			0.1
Actuarial (gain) loss	3.9			2.4			(2.6		)	2.1			0.2			—
Participant contributions	—			—			—			—			0.1			0.1
Gross benefits paid	(7.8		)	(7.8		)	(5.7		)	(3.0		)	(0.4		)	(0.5		)
Currency translation effect	—			—			4.9			(0.3		)	—			—
PBO at end of year	$	124.1		$	123.2		$	30.5		$	32.4		$	1.4		$	1.4
Change in Plan Assets:
Fair value of plan assets at beginning of year	118.9			116.7			6.1			8.4			—			—
Actual return on plan assets	17.6			10.0			0.2			0.1			—			—
Employer contributions	—			—			1.9			0.7			0.3			0.4
Participant contributions	—			—			—			—			0.1			0.1
Gross benefits paid	(7.8		)	(7.8		)	(5.6		)	(2.9		)	(0.4		)	(0.5		)
Currency translation effect	—			—			0.6			(0.2		)	—			—
Fair value of plan assets at end of year	$	128.7		$	118.9		$	3.2		$	6.1		$	—		$	—
Funded status at end of year	$	4.6		$	(4.3	)	$	(27.3	)	$	(26.3	)	$	(1.4	)	$	(1.4	)

Schedule of Accumulated Benefit Obligations and PBO excess of Fair Value of Pension Plan Assets

The PBO, ABO and fair value of pension plan assets for the Company's U.S. and French defined benefit pension plans as of December 31, 2017 and 2016 as follows ($ in millions):



	United States				France
	2017		2016		2017		2016
PBO	$	124.1	$	123.2	$	30.5	$	32.4
ABO	124.1		123.2		25.6		28.2
Fair value of plan assets	128.7		118.9		3.2		6.1

Schedule of Defined Benefit Plan Amounts Recognized in Accumulated Other Comprehensive Income

As of December 31, 2017, the pre-tax amounts in accumulated other comprehensive income that have not been recognized as components of net periodic benefit cost for the U.S. and French pension plans and other postretirement benefit plans in the United States are as follows ($ in millions):



	Pension Benefits					OPEB Benefits
	United States		France			United States
Accumulated loss	$	27.1	$	12.5		$	0.6
Prior service credit	—		(3.4		)	(0.2		)
Accumulated other comprehensive loss	$	27.1	$	9.1		$	0.4

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year

The amounts in accumulated other comprehensive loss at December 31, 2017, which are expected to be recognized as components of U.S. and French net periodic benefit cost in 2018 are as follows ($ in millions):



	Pension Benefits						OPEB Benefits
	United States			France			United States
Amortization of accumulated loss	$	(3.5	)	$	(1.1	)	$	(0.3	)
Amortization of prior service credit	—			0.3			0.1
Total	$	(3.5	)	$	(0.8	)	$	(0.2	)

Schedule of Net Benefit Costs

The components of net pension and OPEB benefit costs for U.S. employees and net pension benefit costs for French employees during the years ended December 31, 2017, 2016 and 2015 were as follows ($ in millions):



	U.S. Pension Benefits									French Pension Benefits									U.S. OPEB Benefits
	2017			2016			2015			2017			2016			2015			2017		2016		2015
Service cost	$	—		$	—		$	—		$	1.1		$	1.0		$	1.3		$	—	$	—	$	—
Interest cost	4.8			5.2			5.0			0.4			0.4			0.4			0.1		0.1		0.1
Expected return on plan assets	(6.4		)	(6.8		)	(7.0		)	(0.2		)	(0.2		)	(0.3		)	—		—		—
Amortizations and other	3.2			3.8			5.1			1.4			1.1			0.2			0.2		0.2		(0.2		)
Net periodic benefit cost	$	1.6		$	2.2		$	3.1		$	2.7		$	2.3		$	1.6		$	0.3	$	0.3	$	(0.1	)

Schedule of Allocation of Plan Assets

The following table sets forth by level, within the fair value hierarchy, the U.S. and French pension plans' assets at fair value as of December 31, 2017 ($ in millions):



	United States										France
Plan Asset Category	Total		Other*		Level 1		Level 2		Level 3		Total		Level 1		Level 2
Cash equivalents	$	1.1	$	—	$	1.1	$	—	$	—	$	1.2	$	1.2	$	—
Equity securities
Domestic large cap	9.0		9.0		—		—		—		1.0		1.0		—
Domestic small cap	5.8		5.8		—		—		—		—		—		—
International	25.3		25.3		—		—		—		—		—		—
Fixed income securities	87.4		31.1		—		56.3		—		0.9		—		0.9
Alternative investments**	0.1		—		—		—		0.1		0.1		—		0.1
Total	$	128.7	$	71.2	$	1.1	$	56.3	$	0.1	$	3.2	$	2.2	$	1.0

The following table sets forth by level, within the fair value hierarchy, the U.S. and French pension plans' assets at fair value as of December 31, 2016 ($ in millions):



	United States										France
Plan Asset Category	Total		Other*		Level 1		Level 2		Level 3		Total		Level 1		Level 2
Cash equivalents	$	1.2	$	—	$	1.2	$	—	$	—	$	1.5	$	1.5	$	—
Equity securities
Domestic large cap	8.3		8.3		—		—		—		1.2		1.2		—
Domestic small cap	5.7		5.7		—		—		—		—		—		—
International	23.7		23.7		—		—		—		—		—		—
Fixed income securities	79.9		79.9		—		—		—		3.2		—		3.2
Alternative investments**	0.1		—		—		—		0.1		0.2		—		0.2
Total	$	118.9	$	117.6	$	1.2	$	—	$	0.1	$	6.1	$	2.7	$	3.4


*	Assets are measured at NAV as a practical expedient and not subject to hierarchy level classification disclosure.

The U.S. and French pension plans' asset target allocations by asset category for 2018 and actual allocations by asset category at December 31, 2017 and 2016 were as follows:



	United States						France
	2018 Target		2017		2016		2017		2016
Asset Category
Cash and cash equivalents	1	%	1	%	1	%	38	%	24	%
Equity securities*
Domestic large cap	7		7		7		31		20
Domestic small cap	4		4		5		—		—
International	20		20		20		—		—
Fixed income securities	68		68		67		28		54
Alternative investments**	—		—		—		3		2
Total	100	%	100	%	100	%	100	%	100	%


*	None of the Company's pension plan assets are targeted for investment in SWM stock, except that it is possible that one or more mutual funds held by the plan could hold shares of SWM.


**	Investments in this category under the U.S. pension plan only may include hedge funds, and may include real estate under the French pension plan.

Schedule of Changes in Plan Assets

The following table shows the changes in Level 3 asset values ($ in millions):



U.S. Level 3 Asset Reconciliation	Alternative Investments Total
Beginning balance, January 1, 2016	$	0.3
Realized and unrealized gains	—
Purchases	—
Sales	(0.2		)
Ending balance, December 31, 2016	$	0.1
Realized and unrealized gains	—
Purchases	—
Sales	—
Ending balance, December 31, 2017	$	0.1

Schedule of Expected Benefit Payments

The Company expects the following estimated undiscounted future pension benefit payments for the United States and France and future postretirement healthcare and life insurance benefit payments for the United States, which are to be made from pension plan and employer assets, net of amounts that will be funded from retiree contributions, and which reflect expected future service, as appropriate ($ in millions):



	United States				France
	Pension Benefits		Healthcare and Life Insurance Benefits		Pension Benefits
2018	$	8.5	$	0.2	$	1.4
2019	8.4		0.1		2.1
2020	8.3		0.1		0.7
2021	8.3		0.1		1.3
2022	8.2		0.1		0.9
2023 - 2027	39.1		0.3		7.7

Benefit Obligations [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule of Assumptions Used

The weighted average assumptions used to determine benefit obligations as of December 31, 2017 and 2016 were as follows:



	Pension Benefits								OPEB Benefits
	United States				France				United States
	2017		2016		2017		2016		2017		2016
Discount rate	3.60	%	4.11	%	1.14	%	1.12	%	3.59	%	4.09	%
Rate of compensation increase	—	%	—	%	1.75	%	1.90	%	3.50	%	3.50	%

Net Periodic Benfit Cost [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule of Assumptions Used

The weighted average assumptions used to determine net periodic benefit costs for the years ended December 31, 2017, 2016 and 2015 were as follows:



	Pension Benefits												OPEB Benefits
	United States						France						United States
	2017		2016		2015		2017		2016		2015		2017		2016		2015
Discount rate	4.11	%	4.40	%	3.94	%	1.14	%	1.12	%	1.43	%	4.09	%	4.29	%	3.82	%
Expected long-term rate of return on plan assets	5.56	%	5.83	%	6.06	%	3.00	%	3.00	%	3.00	%	—	%	—	%	—	%
Rate of compensation increase	—	%	—	%	—	%	1.75	%	1.90	%	1.90	%	3.50	%	3.50	%	3.50	%