Consolidated Statements of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales	$ 776.7		$ 771.3		$ 802.8		$ 709.9		$ 797.8		$ 776.6		$ 826.7		$ 754.4		$ 3,060.7	$ 3,155.5	$ 3,211.9
Cost of goods sold																	1,918.6	2,041.1	2,099.0
Gross profit	299.8		282.4		300.9		259.0		258.3		282.2		301.4		272.5		1,142.1	1,114.4	1,112.9
Selling, general and administrative expenses																	505.7	635.2	659.9
Restructuring expenses and related asset impairments																	12.5	6.9	6.9
Research and development expenses																	65.2	64.5	68.5
Defined Benefit Pension Expense																	(23.2)	149.6	139.9
Interest expense and related financing costs																	43.8	46.5	43.3
Provision for environmental remediation																	8.2	3.6	17.8
Chapter 11 expenses, net of interest income																	15.3	16.6	20.0
Default interest settlement on prepetition debt																	129.0	0	0
Asbestos and bankruptcy-related charges																	21.9	384.6	0
Provision for asbestos-related contingencies																	21.9	384.6	0
Equity in earnings of unconsolidated affiliates																	(22.9)	(18.5)	(15.2)
Other (income) expense, net																	23.5	6.1	29.4
Total costs and expenses																	781.5	1,135.0	805.9
Income before income taxes																	360.6	(20.6)	307.0
Benefit from (provision for) income taxes																	(102.9)	61.6	(87.9)
Net income																	257.7	41.0	219.1
Less: Net loss (income) attributable to noncontrolling interests																	(1.6)	(1.0)	0.6
Net income attributable to W. R. Grace & Co. shareholders	$ 29.7		$ 77.0		$ 90.3		$ 59.1		$ (184.3)		$ 82.1		$ 75.4		$ 66.8		$ 256.1	$ 40.0	$ 219.7
Basic earnings per share:
Net income attributable to W. R. Grace & Co. shareholders (in dollars per share)	$ 0.39	[1]	$ 1.00	[1]	$ 1.18	[1]	$ 0.78	[1]	$ (2.44)	[1]	$ 1.09	[1]	$ 1.01	[1]	$ 0.90	[1]	$ 3.35	$ 0.53	$ 2.99
Weighted average number of basic shares (in shares)																	76.4	74.9	73.6
Diluted earnings per share:
Net income attributable to W. R. Grace & Co. shareholders (in dollars per share)	$ 0.38	[1]	$ 0.99	[1]	$ 1.16	[1]	$ 0.77	[1]	$ (2.44)	[1]	$ 1.07	[1]	$ 0.98	[1]	$ 0.87	[1]	$ 3.30	$ 0.52	$ 2.91
Weighted average number of diluted shares (in shares)																	77.7	76.3	75.5

[1] Per share results for the four quarters may differ from full-year per share results, as a separate computation of the weighted average number of shares outstanding is made for each quarter presented.