Long-term Debt Schedule of Long Term Debt Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Mar. 11, 2020
Debt Instrument [Line Items]
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
Other Loans Payable, Long-Term, Noncurrent	260	0
Pollution Control Revenue Bonds, rates at 2.13% and 2.38%, due 2033	119	119	$ 119
Total long-term debt	3,659	3,299
Less: Unamortized debt expense	(13)	(14)
Less: current portion of long-term debt	(260)	0
Long-term debt, net of current portion	$ 3,386	$ 3,285
First mortgage Bonds - minimum rate	1.82%
First Mortgage Bonds - maximum rate	6.88%
Debt, Weighted Average Interest Rate	4.09%	4.11%