Basis of Presentation, Principles of Consolidation, and Summary of Significant Accounting Policies - Changes to Allowance for Estimated Uncollectible Amounts (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Opening balance	$ 162	$ 158	$ 160	$ 167
Provisions (reversals), net	8	5	16	7
Write-offs against allowance	(14)	(13)	(20)	(26)
Recoveries and other	0	3	0	5
Closing balance	$ 156	$ 153	$ 156	$ 153