Equity - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized For Repurchase	34,000,000
Stock repurchased under the repurchase program	998,356	2,187,382	6,715,000
Stock repurchased under the repurchase program, average price	$ 38.90	$ 36.34
Treasury stock, shares held	20,500,000	21,100,000
Treasury stock repurchased	$ 38,837,000	$ 79,500,000	$ 223,993,000
Proceeds from exercise of stock option	34,183,000	42,275,000	30,189,000
Number of stock option exercised	1,800,000	2,100,000
Tax benefit realized for the options exercised	6,800,000	9,200,000
Intrinsic value of options exercised	21,100,000	27,000,000	16,500,000
Weighted average remaining contractual term of all outstanding options (in years)	5 years 8 months
Weighted average remaining contractual term of exercisable options (in years)	4 years 9 months
Equity Incentive Plan 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized grants under the plan	13,000,000
Percentage threshold of outstanding stock for determining availability of grants under Company Plan	7.00%
Number of shares available for grant	10,500,000
Equity Incentive Plan 2010 | Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cap on restricted stock or RSU	2,500,000
Equity Incentive Plan 2010 | Key Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cap on restricted stock or RSU	200,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation costs	15,000,000
Weighted average remaining contractual term of all outstanding options (in years)	1 year 3 months
Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock option exercised	1,409,000
Number of unvested stock options	2,300,000
Unamortized compensation costs	$ 13,500,000
Weighted average remaining contractual term of all outstanding options (in years)	1 year 7 months
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term (in years)	10 years