Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income (loss)	$ 126.7	$ 166.8	$ 10.4
Other comprehensive income (loss):
Defined benefit pension and other postretirement plans	(0.7)	(0.9)	(1.3)
Currency translation adjustments	16.5	32.4	(26.0)
Gain (loss) from hedging activities	(4.9)	(5.7)	0.8
Total other comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0	0.0
Total other comprehensive income (loss), net of income taxes	10.9	25.8	(26.5)
Comprehensive income (loss)	137.6	192.6	(16.1)
Less: comprehensive (income) loss attributable to noncontrolling interests	(0.4)	0.8	0.8
Comprehensive income (loss) attributable to W. R. Grace & Co. shareholders	$ 137.2	$ 193.4	$ (15.3)