Income Taxes - Summary of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Deferred tax liabilities:
Attributable to investment in OTA	$ 505	$ 495
Attributable to property, plant and equipment	182	172
Other	110	111
Total deferred tax liabilities	797	778
Deferred tax assets:
Net operating loss carryovers	74	73
Temporary differences related to Texas Margin Tax	3	3
Total deferred tax assets	77	76
Total net deferred tax liabilities	$ 720	$ 702