Stockholders' Equity - Shares of Common Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares)	219,012,050	226,126,674	228,605,485
Incentive Plan and Awards (in shares)	1,688,931	1,310,778	1,320,129
Stock Options Exercised (in shares)	786,931	575,662	1,997,362
Treasury Stock Purchased (in shares)	(11,778,866)	(9,001,064)	(5,796,302)
Ending balance (in shares)	209,709,046	219,012,050	226,126,674