Equity (Treasury Stock) - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended			9 Months Ended
	Apr. 12, 2016	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Apr. 12, 2016	Sep. 30, 2015	Dec. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Payments for repurchase of common stock			$ 172,279,000			$ 354,279,000
2015 Repurchase Program [Member] | Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Aggregate authorized amount of common stock to be repurchased		$ 1,250,000,000						$ 1,250,000,000
2015 Repurchase Program Open Market Purchases [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired					19,200,000
Value of treasury stock acquired, cost method					$ 449,900,000
2013 Repurchase Program [Member] | Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Aggregate authorized amount of common stock to be repurchased									$ 500,000,000
2013 Repurchase Program Open Market Repurchases [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired								14,300,000
Value of treasury stock acquired, cost method								$ 406,500,000
Accelerated Share Repurchase Agreement [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired	9,400,000	25,700,000
Value of treasury stock acquired, cost method		$ 600,000,000
Aggregate authorized amount of common stock to be repurchased		750,000,000						$ 750,000,000
Payments for repurchase of common stock		750,000,000
Accelerated stock repurchases not yet settled		$ 150,000,000
2015 Repurchase Plan Open Market Purchases And Accelerated Share Repurchase Agreement [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired							54,300,000
Value of treasury stock acquired, cost method							$ 1,200,000,000
Treasury stock remaining authorized repurchase amount	$ 50,100,000						$ 50,100,000
Common Stock Withheld for Settlement of Employee Tax Liabilities [Member] | Treasury Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock acquired				352,061		345,083
Value of treasury stock acquired, cost method				$ 7,200,000		$ 9,900,000