Long term debt (Tables)

12 Months Ended

Dec. 31, 2022

Long-Term Debt, Unclassified [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

Long-term debt consists of the following (in millions):

	As of December 31,
	2022		2021
First Mortgage Bonds, rates range from 1.82% to 6.88%, with a weighted average rate of 4.09% in 2022 and 4.11% in 2021, due at various dates through 2051	$	3,280	$	3,180
Unsecured term bank loans, variable rate of approximately 5.30% at December 31, 2022	260		—
Pollution Control Revenue Bonds, rates at 2.13% and 2.38%, due 2033	119		119
Total long-term debt	3,659		3,299
Less: Unamortized debt expense	(13)		(14)
Less: Current portion of long-term debt	(260)		—
Long-term debt, net of current portion	$	3,386	$	3,285

Schedule of Maturities of Long-term Debt [Table Text Block]

As of December 31, 2022, the future minimum principal payments on long-term debt are as follows (in millions):

Years ending December 31:
2023	$	260
2024	80
2025	—
2026	—
2027	160
Thereafter	3,159
	$	3,659

Lessee, Operating Lease, Liability, Maturity

As of December 31, 2022, the future minimum payments on the financing arrangement are as follows (in millions):

Years ending December 31:
2023	$	2
2024	2
2025	5
2026	5
2027	5
Thereafter	69
Total Payments	88
Less: Imputed Interest	(61)
Present value of minimum payments	$	27