Pension Plans and Other Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2018

Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]

Schedule of net funded status of fully funded, underfunded, and unfunded pension plans

The following table presents the funded status of Grace’s pension plans:

(In millions)	September 30, 2018			December 31, 2017
Overfunded defined benefit pension plans	$	4.7		$	—
Underfunded defined benefit pension plans	(63.2		)	(110.5		)
Unfunded defined benefit pension plans	(392.3		)	(391.9		)
Total underfunded and unfunded defined benefit pension plans	(455.5		)	(502.4		)
Pension liabilities included in other current liabilities	(14.9		)	(15.0		)
Net funded status	$	(465.7	)	$	(517.4	)

Components of net periodic benefit cost (income)

The following tables present the components of net periodic benefit cost (income).

	Three Months Ended September 30,
	2018						2017
(In millions)	U.S.			Non-U.S.			U.S.			Non-U.S.
Service cost	$	4.9		$	2.3		$	4.3		$	2.2
Interest cost	10.3			1.3			10.5			1.1
Expected return on plan assets	(14.5		)	(0.3		)	(14.4		)	(0.2		)
Amortization of prior service credit	(0.2		)	—			(0.1		)	—
Net periodic benefit cost (income)	$	0.5		$	3.3		$	0.3		$	3.1

	Nine Months Ended September 30,
	2018						2017
(In millions)	U.S.			Non-U.S.			U.S.			Non-U.S.
Service cost	$	14.6		$	7.2		$	12.9		$	6.2
Interest cost	30.9			3.8			31.5			3.2
Expected return on plan assets	(43.6		)	(0.8		)	(43.2		)	(0.6		)
Amortization of prior service credit	(0.5		)	—			(0.3		)	—
Net periodic benefit cost (income)	$	1.4		$	10.2		$	0.9		$	8.8