Equity (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount		$ 1,200,000,000.0		$ 1,200,000,000.0
Treasury stock, average price paid per share (in dollars per share)		$ 98.03	$ 84.03	$ 84.00	$ 82.34
Purchases of treasury stock	$ 7,200,000	$ 6,480,000	$ 117,400,000	$ 51,967,000	$ 441,442,000