Basis of Presentation and Significant Accounting Policies and Practices - Additional Information (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Advertising expense	$ 28	$ 30	$ 34
Antidilutive securities excluded from computation of earnings per share, Amount (in shares)	4	6	4
Maximum length to maturity of a security, from the investment date, where it is classified as cash and cash equivalent	90 days
Length to maturity from the investment date of a security where the length of time is too short to be classified as a short-term investment	90 days