Long-term Debt Schedule of Long Term Debt Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Mar. 11, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
First mortgage Bonds - minimum rate	1.84%
First Mortgage Bonds, rates range from 2.51% to 9.31%, with a weighted average rate of 4.63% in 2019 and 5.01% in 2018, due at various dates through 2050	$ 2,940		$ 2,510
Pollution Control Revenue Bonds, 5% rate, due 2033	119	$ 119	119
Pollution Control Revenue Bonds owned by PGE	0		(21)
Total long-term debt	3,059		2,608
Debt Instrument, Unamortized Discount	(13)		(11)
Less: current portion of long-term debt	(160)		0
Long-term debt, net of current portion	$ 2,886		$ 2,597
First Mortgage Bonds - maximum rate	9.31%
Debt, Weighted Average Interest Rate	0.00%