Accumulated Other Comprehensive Income (Reclassifications Out Of Accumulated Other Comprehensive Income) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Amortization of defined benefit pension items:
Total net periodic benefit cost, net of tax	$ (3.0)		$ (3.4)
Amount Reclassified From Accumulated Other Comprehensive Income [Member]
Amortization of defined benefit pension items:
Prior service cost	(0.3)	[1],[2]
Recognized actuarial loss	(4.4)	[1],[2]
Total net periodic benefit cost, before tax	(4.7)	[1]
Total net periodic benefit cost, tax benefit	1.8	[1]
Total net periodic benefit cost, net of tax	$ (2.9)	[1]

[1] Amounts in parentheses indicate expense recognized in the Consolidated Statements of Income.

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (See Note 8 Benefit Plans for additional details).