The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

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Unconsolidated Affiliate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Unconsolidated Affiliate (Details) - USD ($) $ in Millions	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Investment in unconsolidated affiliates
Equity method investment, ownership interest (as a percent)	50.00%		50.00%
Investment in unconsolidated affiliate	$ 108.7		$ 108.7		$ 113.1
Equity in earnings of unconsolidated affiliate	2.3	$ 3.1	8.5	$ 6.8
Grace sales of catalysts to ART	63.3	64.5	117.5	130.0
Charges for fixed costs, research and development and selling, general and administrative services to ART	5.9	$ 7.1	$ 11.8	$ 14.6
Commitment fee on credit facility (as a percent)			0.10%
Parent Company [Member]
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	15.0		$ 15.0
Corporate Joint Venture [Member]
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15.0		$ 15.0