Income Taxes - Allocation of Total Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Benefit/(Loss) Applicable To: [Abstract]
Loss from continuing operations, before income taxes	$ 168.2	$ 113.2	$ 322.7	$ 402.6
Discontinued operations	0	2.5	0	6.2
Other Comprehensive Income (Loss), Tax	$ 0	$ (0.3)	$ 0.1	$ 1.2
Effective tax rate benefit	29.30%	35.70%	31.50%	51.60%