Unrecognized tax benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance at Beginning of Year	$ 17.5	$ 86.9	$ 138.9
Tax Positions Related to Prior Years - Additions	5.7	13.3	4.4
Tax Positions Related to Prior Years - Subtractions	0	(0.6)	(11.8)
Settlements with Tax Authorities	(4.8)	(23.5)	(44.6)
Lapses of Statute of Limitations	0	(61.1)	0
Tax Positions Taken During Current Year	0	2.5	0
Balance at End of Year	18.4	17.5	86.9
Less Tax Attributable to Temporary Items Included Above	(10.2)	(15.0)	(86.9)
Total Unrecognized Tax Benefits that if Recognized Would Affect the Effective Tax Rate	$ 8.2	$ 2.5	$ 0