Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Customer accounts receivable, net of allowance for doubtful accounts	$ 21	$ 22
Equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	100,000,000	100,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	1,500,000,000	1,500,000,000
Common stock, issued (in shares)	635,000,000	634,000,000
Common stock, outstanding (in shares)	559,000,000	559,000,000
Treasury stock (in shares)	76,000,000	75,000,000