Effect of Revision on Previously Reported Amounts, Income Statement (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2012	Sep. 30, 2012
Parent Company
Condensed Financial Statements, Captions [Line Items]
Income tax provision (benefit)	$ (70.1)	$ (58.3)	$ (38.6)	$ (96.9)	$ (167.0)
Equity earnings of subsidiaries	(70.1)	(58.3)	(38.6)	(96.9)	(167.0)
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Income tax provision (benefit)	50.3	46.9	30.9	77.8	128.1
Equity earnings of subsidiaries	(19.8)	(11.4)	(7.7)	(19.1)	(38.9)
Net income (loss)	(70.1)	(58.3)	(38.6)	(96.9)	(167.0)
Comprehensive income (loss)	(70.1)	(58.3)	(38.6)	(96.9)	(167.0)
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Income tax provision (benefit)	19.8	11.4	7.7	19.1	38.9
Net income (loss)	(19.8)	(11.4)	(7.7)	(19.1)	(38.9)
Comprehensive income (loss)	(19.8)	(11.4)	(7.7)	(19.1)	(38.9)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Equity earnings of subsidiaries	89.9	69.7	46.3	116.0	205.9
Net income (loss)	89.9	69.7	46.3	116.0	205.9
Comprehensive income (loss)	$ 89.9	$ 69.7	$ 46.3	$ 116.0	$ 205.9