Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Millions |
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2026 |
May 01, 2026 |
Dec. 31, 2025 |
|
| Basis of Presentation | |||
| Gain or loss on deconsolidation of consolidated variable interest entity | $ 0 | ||
| Location, Statement of Financial Position, Balance [Axis]: us-gaap:AccountsPayableCurrent | |||
| Basis of Presentation | |||
| Book overdrafts | 12 | $ 18 | |
| Location, Statement of Financial Position, Balance [Axis]: ar:RevenueDistributionsPayableCurrent | |||
| Basis of Presentation | |||
| Book overdrafts | $ 22 | $ 18 | |
| ORRI | |||
| Basis of Presentation | |||
| Percentage of distributions received | 85.00% |