Capital Stock, Dividends and Common Stock Repurchase Program (Detail) $ / shares in Units, shares in Thousands, $ in Millions	2 Months Ended	12 Months Ended
	Feb. 14, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) item $ / shares shares	Dec. 31, 2017 USD ($) item $ / shares shares
Accelerated Share Repurchases [Line Items]
Cash paid for repurchase of common stock		$ 248	$ 1,004	$ 750
Shares repurchased (in shares) | shares		2,247	11,673	10,058
Total repurchases		$ 244	$ 1,008	$ 750
Weighted average per share purchase price | $ / shares		$ 108.60	$ 86.35	$ 77.67
Authorized share repurchases		$ 1,320
10b5-1 Plan [Member]
Accelerated Share Repurchases [Line Items]
Cash paid for repurchase of common stock	$ 4
Shares repurchased (in shares) | shares		700	1,900
Total repurchases		$ 64	$ 158
Accelerated Share Repurchase Agreement (ASR) [Member]
Accelerated Share Repurchases [Line Items]
Cash paid for repurchase of common stock		$ 180	$ 850	$ 750
Shares repurchased (in shares) | shares		1,600	9,800	400
Number of ASR agreements | item			4	2