Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended			3 Months Ended				9 Months Ended			9 Months Ended	3 Months Ended		9 Months Ended				3 Months Ended	9 Months Ended	0 Months Ended
	Jul. 11, 2013	Apr. 11, 2013	Feb. 14, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Stock Appreciation Rights (SARs)	Sep. 30, 2013 Stock Appreciation Rights (SARs) General and Administrative Expense	Sep. 30, 2012 Stock Appreciation Rights (SARs) General and Administrative Expense	Sep. 30, 2013 Stock Appreciation Rights (SARs) General and Administrative Expense	Sep. 30, 2012 Stock Appreciation Rights (SARs) General and Administrative Expense	Sep. 30, 2013 Stock Appreciation Rights (SARs) General and Administrative Expense Other Current Liabilities	Sep. 30, 2013 Stock Appreciation Rights (SARs) General and Administrative Expense Other Noncurrent Liabilities	Sep. 30, 2013 Stock Appreciation Rights (SARs) Restructuring Charges	Sep. 30, 2013 Stock Appreciation Rights (SARs) Restructuring Charges	Oct. 10, 2013 Subsequent Event	Oct. 31, 2013 Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividends declared per common share	$ 0.13	$ 0.13	$ 0.13																	$ 0.13
Estimated dividend payable																				$ 25
Common stock, shares outstanding				196,148,264				196,148,264		194,557,669											196,000,000
Common stock dividends, cash paid					25	25
SARs outstanding											1,400,000
Weighted average remaining vesting life											1 year
Compensation expense				8.7			2.9	26.8	5.6			9.0	3.0	27.0	6.0			1.0	1.0
Payment due to exercise SARs														43	23				2
Liability for SARs												25		25		8	17	1	1
Unrecognized pension items				137.5				137.5		142.3
Reclassification from accumulated other comprehensive income, before tax								7
Reclassification from accumulated other comprehensive income, net of tax								$ 5