Pensions And Other Postretirement Benefits (Components Of Net Periodic Benefit Cost) (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 Pension Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8.0	$ 5.2	$ 16.0	$ 11.0
Interest cost	12.3	12.2	24.3	25.8
Expected return on plan assets	(15.0)	(13.7)	(29.8)	(29.2)
Prior service costs	0.9	1.0	1.9	2.2
Net actuarial loss	7.6	4.8	15.0	10.0
Net periodic benefit cost	13.8	9.5	27.4	19.8
Quarterly pension contributions	7.6	3.5	24.9	27.3
Other Postretirement Benefits Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3.9	2.3	7.5	4.7
Interest cost	5.4	5.3	10.6	11.2
Expected return on plan assets	(4.3)	(3.7)	(8.6)	(8.0)
Prior service costs	0.8	0.2	1.5	0.8
Net actuarial loss	2.7	2.9	5.6	5.8
Net periodic benefit cost	8.5	7.0	16.6	14.5
Quarterly OPEB contributions			$ 21.9	$ 21.9