Capital Stock - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares Directors shares	Dec. 31, 2018 $ / shares shares	Dec. 31, 2017 $ / shares shares	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Oct. 31, 2017 USD ($)	Nov. 30, 2016 USD ($)
Capital Structure [Line Items]
Common stock, shares authorized | shares	1,800,000,000	1,800,000,000
Repurchase of common stock, shares | shares	7,949,000	14,070,000.000	25,092,000.000
Repurchase price of common stock, per share | $ / shares	$ 129.71	$ 108.74	$ 81.73
Share repurchase program authorized amount | $				$ 8,000,000,000	$ 8,000,000,000	$ 8,000,000,000	$ 8,000,000,000
Share repurchase program, remaining authorized repurchase amount | $	$ 1,241,000,000			$ 2,000,000,000	$ 2,000,000,000	$ 2,000,000,000	$ 2,000,000,000
Minimum [Member]
Capital Structure [Line Items]
Number of directors as per the amended and restated by-laws | Directors	3