Long-term Debt Schedule of Long Term Debt Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
First Mortgage Bonds, rates range from 3.46% to 9.31%, with a weighted average rate of 5.42% in 2014 and 5.62% in 2013, due at various dates through 2048	$ 2,090	$ 2,083
Unsecured Debt, Current	150	0
Pollution Control Revenue Bonds, 5% rate, due 2033	142	142
Pollution Control Revenue Bonds owned by PGE	(21)	(21)
Debt Instrument, Unamortized Discount	(11)	(11)
Total long-term debt	2,361	2,204
Less: current portion of long-term debt	(150)	(133)
Long-term debt, net of current portion	$ 2,200	$ 2,060