Leases - Schedule of Supplemental Balance Sheet (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating leases
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets (Note 9)	Other assets (Note 9)	Other assets (Note 9)
Other assets	$ 860	$ 860	$ 796
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other accrued liabilities (Notes 9 and 12)	Other accrued liabilities (Notes 9 and 12)	Other accrued liabilities (Notes 9 and 12)
Other accrued liabilities	$ 97	$ 97	$ 95
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other liabilities (Notes 9 and 12)	Other liabilities (Notes 9 and 12)	Other liabilities (Notes 9 and 12)
Other liabilities	$ 846	$ 846	$ 785
Total operating lease liabilities	943	943	880
Finance leases
Property, plant and equipment	1,279	1,279	265
Accumulated depreciation	$ (147)	$ (147)	$ (118)
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net of accumulated depreciation - $15,229 and $14,492 (Note 6)	Property, plant and equipment, net of accumulated depreciation - $15,229 and $14,492 (Note 6)	Property, plant and equipment, net of accumulated depreciation - $15,229 and $14,492 (Note 6)
Property, plant and equipment, net	$ 1,132	$ 1,132	$ 147
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current portion of long-term debt and short-term borrowings (Note 10)	Current portion of long-term debt and short-term borrowings (Note 10)	Current portion of long-term debt and short-term borrowings (Note 10)
Current portion of long-term debt and short-term borrowings	$ 84	$ 84	$ 30
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt	Long-term debt	Long-term debt
Long-term debt	$ 1,148	$ 1,148	$ 144
Total finance lease liabilities	1,232	1,232	174
Finance leases		1,389	21	$ 30
Financing cash outflows from finance leases		346	$ 30	$ 36
Government Incentives, 48D Credits
Finance leases
Right-of-use asset, tax incentive	318	318
Facility Lease
Finance leases
Property, plant and equipment, net	797	797
Long-term debt	797	797
Financing cash outflows from finance leases	315	315
Facility Lease | Government Incentives, 48D Credits
Finance leases
Right-of-use asset, tax incentive	$ 189	$ 189