CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
ASSETS
Allowance for doubtful accounts	$ 116	$ 112
LIABILITIES AND STOCKHOLDERS’ EQUITY
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	114,687,661	114,434,075
Common stock, shares outstanding (in shares)	71,867,762	72,420,566
Treasury stock, shares (in shares)	42,819,899	42,013,509