Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Customer accounts receivable, net of allowance for doubtful accounts	$ 21	$ 21
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)	651,000,000	649,000,000
Common stock, outstanding (in shares)	574,000,000	573,000,000
Treasury stock (in shares)	(77,000,000)	(76,000,000)