Accounts Receivable Accounts Receivable (Activity in the Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions  | 
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2024  | 
Dec. 31, 2023  | 
Dec. 31, 2022  | 
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| Accounts Receivable, Allowance for Credit Loss [Roll Forward] | |||
| Balance beginning of year | $ 101 | $ 102 | $ 99 | 
| Additions- charged to expense | 57 | 58 | 80 | 
| Deductions- write-offs | (69) | (59) | (77) | 
| Balance end of year | $ 89 | $ 101 | $ 102 | 
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- Definition Amount of allowance for credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition Amount of direct write-downs of accounts receivable charged against the allowance. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of expense (reversal of expense) for expected credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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