Capital Stock, Dividends and Common Stock Repurchase Program - Repurchases (Detail) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2019 $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares
Capital Stock, Dividends and Common Stock Repurchase Program
Common stock, shares authorized | shares	1,500,000,000	1,500,000,000	1,500,000,000
Common stock, par value | $ / shares	$ 0.01	$ 0.01	$ 0.01
Common stock, shares issued | shares	630,282,461	630,282,461	630,282,461
Number of common shares outstanding | shares	424,300,000	424,300,000	424,000,000.0	433,300,000
Preferred stock shares authorized | shares	10,000,000	10,000,000
Preferred stock par value per share | $ / shares	$ 0.01	$ 0.01
Preferred stock shares outstanding | shares	0	0
Cash dividends | $		$ 876	$ 802	$ 750
Cash dividends declared and paid per common share | $ / shares		$ 2.05	$ 1.86	$ 1.70
Quarterly common stock dividend per share | $ / shares	0.5125
Expected quarterly common stock dividend per share | $ / shares	$ 0.545