Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits - January 1	$ 208.8	$ 198.7	$ 203.4
Additions for:
Prior year tax positions	1.6	48.4	1.5
Current year tax positions	8.0	0.8	15.1
Assumed in acquisition	0	3.8	0
Reductions for:
Prior year tax positions	(55.4)	(4.8)	(21.2)
Settlements	(1.0)	(33.6)	0
Lapse of statute	(0.8)	(4.5)	(0.1)
Unrecognized tax benefits - December 31	$ 161.2	$ 208.8	$ 198.7