Earnings Per Common Share - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive effect on computation of diluted earnings per common share	14,000,000	34,000,000	14,000,000	34,000,000
Grant of long term stock awards			1,000,000	1,000,000
Repurchase and retirement of common stock to offset the dilutive impact of long term stock awards			1,700,000
Repurchase and retirement of common stock cash aggregate to offset the dilutive effect			$ 35
Common stock outstanding under repurchase authorization	22,600,000		22,600,000
Cash dividends per common share paid	$ 0.075	$ 0.075	$ 0.150	$ 0.150
Cash dividends per common share declared	$ 0.075	$ 0.075	$ 0.150	$ 0.150
Long-Term Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Grant of long term stock awards			1,600,000