Stockholders' Equity (Deficit) Accumulated Other Comprehensive Income and Redeemable Noncontrolling Interest - Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) (USD $) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Foreign Currency Translation [Member]	Sep. 30, 2014 Benefit Plan Liabilities [Member]	Sep. 30, 2014 Unrealized Gain (Loss) on Available-For-Sale Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) net of tax, beginning balance	$ (200.8)	$ (189.9)	$ (18.3)	$ (174.9)	$ 3.3
Other comprehensive income (loss) before reclassifications			(9.9)	3.9	(5.5)
Reclassification from accumulated other comprehensive income, period net of tax				0.6
Net current-period other comprehensive income (loss)			(9.9)	4.5	(5.5)
Accumulated other comprehensive income (loss) net of tax, ending balance	$ (200.8)	$ (189.9)	$ (28.2)	$ (170.4)	$ (2.2)