Unconsolidated Affiliates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]
Equity method investment, ownership interest	50.00%
Investment in unconsolidated affiliate	$ 103.2	$ 113.1
Equity in earnings of unconsolidated affiliates	20.4	19.7	$ 22.9
ART's assets, liabilities and results of operations:
Current assets	244.2	216.9
Noncurrent assets	69.7	59.3
Total assets	313.9	276.2
Current liabilities	111.3	54.7
Total liabilities	111.3	54.7
Net sales	415.7	409.9	370.4
Costs and expenses applicable to net sales	367.2	358.1	311.2
Income before income taxes	42.6	41.2	46.6
Net income	40.9	39.7	45.6
Related party transactions:
Grace sales of catalysts to ART	258.9	266.4	232.0
Charges for fixed costs, research and development and selling, general and administrative services to ART	$ 23.4	$ 26.9	$ 28.8
Schedule of Investments [Line Items]
Commitment fee on credit facility	0.10%
Corporate Joint Venture [Member]
Schedule of Investments [Line Items]
Line of credit facility, maximum provided by Grace and Chevron each	$ 15.0
W R Grace & Co. [Member]
Schedule of Investments [Line Items]
Line of credit facility, maximum provided by Grace and Chevron each	$ 15.0