Capital Stock - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Oct. 31, 2017 USD ($) $ / shares shares	May 31, 2016 $ / shares shares	Dec. 31, 2017 $ / shares Directors shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Nov. 30, 2016 USD ($)	Oct. 31, 2015 USD ($)	May 31, 2015 USD ($)	Apr. 30, 2015 shares	Feb. 28, 2015 USD ($)
Capital Structure [Line Items]
Common stock, shares authorized			1,800,000,000	1,800,000,000
Repurchase of common stock, shares	25,092,000		25,092,000	36,325,000	31,991,000
Repurchase price of common stock, per share | $ / shares	$ 81.73			$ 75.72	$ 74.62
Share repurchase program, remaining authorized repurchase amount | $	$ 1,802,000			$ 1,853,000,000
Share repurchase program authorized amount | $	$ 2,000,000,000			$ 3,000,000,000		$ 2,000,000,000	$ 3,000,000,000	$ 1,000,000,000		$ 1,000,000,000
Repurchase of common stock, shares			31,991,000		28,185,000
Stock repurchase program, authorized per share | $ / shares			$ 74.93
Share Repurchase Program Two [Member]
Capital Structure [Line Items]
Repurchase of common stock, shares				26,964,000
Repurchase price of common stock, per share | $ / shares				$ 74.20
Share Repurchase Transaction, October, 2015 [Member]
Capital Structure [Line Items]
Share repurchase program, remaining authorized repurchase amount | $					$ 2.603
Kohlberg Kravis Roberts & Co [Member] | Share Repurchase Program One [Member]
Capital Structure [Line Items]
Repurchase of common stock, shares		9,361,000
Repurchase price of common stock, per share | $ / shares		$ 80.12
Percentage of discount on share repurchase		1.00%
The Bain Entities [Member]
Capital Structure [Line Items]
Repurchase price of common stock, per share | $ / shares					$ 77.26
Percentage of discount on share repurchase					1.00%
Repurchase of common stock, shares									3,806,000
Minimum [Member]
Capital Structure [Line Items]
Number of directors as per the amended and restated by-laws | Directors			3