Stockholders Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended		3 Months Ended	9 Months Ended	1 Months Ended
	Sep. 30, 2013	Apr. 30, 2012	Mar. 31, 2013 Employee Stock Purchase Plan Twenty Thirteen	Sep. 30, 2013 Employee Stock Purchase Plan Twenty Thirteen	Oct. 28, 2013 Dividend Declared Two Thousand Thirteen Fourth Quarter	Oct. 30, 2013 Subsequent Event Share Repurchases
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends declaration date					Oct. 28, 2013
Dividends per share					$ 0.15
Dividend payment date					Dec. 12, 2013
Dividend record date					Nov. 21, 2013
Authorized share repurchase		20,000,000
Stock repurchased, shares	6,300,000					1,700,000
Stock repurchased, value	$ 348					$ 87
Average repurchase price per share	$ 55.01					$ 52.06
Shares authorized and remaining under the repurchase program	11,700,000
Common stock purchase price as percentage of fair market value			85.00%
Eligible employees contribution of base compensation			10.00%
Shares of our common stock reserved for issuance				1,500,000
Employee stock purchase plan, shares purchased				37,000
Employee stock ownership plan, average purchase price of shares purchased				$ 39.75