Deb - 3.500% Senior Unsecured Notes Due 2031 - Additional Information (Detail) - 3.500% Senior Unsecured Notes Due 2031 [Member] - USD ($)		12 Months Ended
	Dec. 04, 2020	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Senior unsecured notes face amount	$ 1,300,000,000
Senior unsecured notes, interest rate	3.50%	3.50%	3.50%
Senior unsecured notes, payable term		Interest on the notes is payable semi-annually on March 15 and September 15 of each year.
Debt instrument maturity date	Mar. 15, 2031