Employee Benefit Plans (Narrative) (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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts expensed to savings plans and profit growth sharing plans	$ 5.1	$ 5.0	$ 12.3	$ 13.5
Building Block Chemicals
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts expensed to savings plans and profit growth sharing plans	0.7	0.8	1.6	2.6
Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected future contributions	40.7		40.7
Expected contributions to continuing plans			35.5
Contributions made during the period			18.3
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected future contributions	11.2		11.2
Expected contributions to continuing plans			11.2
Contributions made during the period			$ 7.4