Employee Benefit Plans (Costs Disclosed To Discontinued Operations) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Periodic cost in discontinued operations	$ 0.9	[1]	$ 0.7	[1]	$ 1.8	[1]	$ 2.0	[1]
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Periodic cost in discontinued operations	$ 0.4	[1]	$ 0.1	[1]	$ 0.8	[1]	$ (0.9)	[1]

[1] Six months ended June 30, 2011 includes a pension curtailment charge of $0.1 and a postretirement plan curtailment gain of $1.1 resulting from the sale of our former Building Block Chemicals segment, which are included in gain on sale of discontinued operations, net of tax in the consolidated statements of income.