Employee Benefit Plans (Net Periodic Cost For Pension And postretirement Benefit Plans) (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 Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.5	$ 1.3	$ 3.0		$ 2.8
Interest cost	10.0	10.7	20.0		21.3
Expected return on plan assets	(12.1)	(12.2)	(24.2)		(24.2)
Net amortization	6.7	5.0	13.4		10.1
Net periodic cost	6.1	4.8	12.2		10.1
Curtailment loss (gain)			0	[1]	0.1	[1]
Pension Plans, Defined Benefit | Building Block Chemicals
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment loss (gain)					0.1
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.4	0.2	0.7		0.5
Interest cost	2.3	2.9	4.6		5.7
Expected return on plan assets	(0.5)	(0.7)	(1.0)		(1.4)
Net amortization	0.4	(1.6)	0.9		(3.4)
Net periodic cost	2.6	0.8	5.2		0.3
Curtailment loss (gain)			0	[1]	(1.1)	[1]
Other Postretirement Benefit Plans, Defined Benefit | Building Block Chemicals
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment loss (gain)					$ 1.1

[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.