Components of Net Pension and Postretirement Benefits (Income) Expense and Total (Income) Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Gain on pension curtailment		$ (3.7)	$ (38.7)
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.2	5.9	86.6
Interest cost	178.2	189.2	192.0
Expected return on plan assets	(241.9)	(262.6)	(266.4)
Amortization of prior service credit		0.6	(4.4)
Amortization of actuarial loss (gain)	50.5	32.1	50.1
Gain on pension curtailment		(3.7)	(38.7)
Settlements	0.7	1.1
Net periodic benefit (income) expense	(10.3)	(37.4)	19.2
Discount rate	4.20%	4.90%	5.50%
Rate of compensation increase	0.30%	0.90%	4.00%
Expected return on plan assets	7.90%	8.40%	8.40%
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	7.3	6.6	8.2
Interest cost	16.2	18.4	22.7
Expected return on plan assets	(11.8)	(13.9)	(14.8)
Amortization of prior service credit	(19.7)	(19.7)	(12.5)
Amortization of actuarial loss (gain)		(0.1)	0.1
Gain on pension curtailment
Settlements
Net periodic benefit (income) expense	$ (8.0)	$ (8.7)	$ 3.7
Discount rate	3.90%	4.80%	5.20%
Rate of compensation increase		3.60%	3.60%
Expected return on plan assets	7.30%	7.60%	7.60%