SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reconciliation of valuation and reserves roll forward
Income Tax Reconciliation Release of State Valuation Allowance	$ (24.4)		$ (44.0)
Allowances for notes and accounts receivable
Reconciliation of valuation and reserves roll forward
Balance at beginning of period	6.9		9.8		8.7
Additions charged to costs and expenses	2.2		1.9		2.9
Deductions	(1.6)		(4.8)		(2.0)
Other net	0.1	[1]	0	[1]	0.2	[1]
Balance at end of period	7.6		6.9		9.8
Valuation allowance for deferred tax assets
Reconciliation of valuation and reserves roll forward
Balance at beginning of period	40.8	[2]	100.8	[2]	104.6	[2]
Additions charged to costs and expenses	4.4	[2]	0	[2]	0	[2]
Deductions	(24.4)	[2]	(60.0)	[2]	(3.8)	[2]
Other net	(2.5)	[1],[2]	0	[1],[2]	0	[1],[2]
Balance at end of period	18.3	[2]	40.8	[2]	100.8	[2]
Reserves for asbestos related litigation
Reconciliation of valuation and reserves roll forward
Balance at beginning of period	2,065.0		1,700.0		1,700.0
Additions charged to costs and expenses	27.4		365.0		0
Deductions	0		0		0
Other net	0	[1]	0	[1]	0	[1]
Balance at end of period	2,092.4		2,065.0		1,700.0
Reserves for environmental remediation
Reconciliation of valuation and reserves roll forward
Balance at beginning of period	140.5		149.9		144.0
Additions charged to costs and expenses	8.0		3.6		17.8
Deductions	(14.0)		(13.0)		(11.8)
Other net	0	[1]	0	[1]	(0.1)	[1]
Balance at end of period	134.5		140.5		149.9
Reserves for retained obligations of divested businesses
Reconciliation of valuation and reserves roll forward
Balance at beginning of period	34.2		33.7		33.9
Additions charged to costs and expenses	0.8		0.7		0.4
Deductions	0		(0.2)		(0.6)
Other net	0	[1]	0	[1]	0	[1]
Balance at end of period	35.0		34.2		33.7
Net Operating Loss Carryforwards [Member] | State and Local Jurisdiction [Member]
Reconciliation of valuation and reserves roll forward
Reduction in valuation allowance	$ 22.5

[1] Various miscellaneous adjustments against reserves and effects of currency translation.

[2] The valuation allowance decreased $22.5 million from December 31, 2012, to December 31, 2013. In the 2013 fourth quarter, Grace determined that it is more likely than not that its deductions generated at emergence will be used before their expiration. Accordingly, Grace recorded a $24.4 million release of its valuation allowance on its state deferred tax assets. Further decreases in Grace’s deferred tax assets resulted from the utilization and expiration of state net operating losses ("NOLs") in the current year, and the reduction of NOLs resulting from prior-year adjustments to taxable income. These decreases were partially offset by the recording of valuation allowance on deferred tax assets associated with certain U.S. federal foreign tax credits. The reduction in the valuation allowance during 2012 related in part to a $44.0 million release of the valuation allowance as Grace determined that it is more likely than not that a substantial portion of its state net operating losses will be used before their expiration; the remainder of the release related to the utilization and expiration of state net operating losses in the current year, and the reduction of net operating losses resulting from prior-year adjustments made to income by the Internal Revenue Service. The reduction in 2011 primarily related to the utilization and expiration of state net operating losses.