CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 17	$ 20
Accumulated depreciation	$ 2,072	$ 1,952
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	6,000,000,000	6,000,000,000
Common stock, shares issued	501,891,243	501,891,243
Common stock, shares outstanding	472,574,090	475,317,751
Treasury shares	29,317,153	26,573,492
Restricted cash	$ 3	$ 2