Long term debt (Tables)

12 Months Ended

Dec. 31, 2016

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,
	2016			2015
First Mortgage Bonds, rates range from 2.51% to 9.31%, with a weighted average rate of 4.86% in 2016 and 5.29% in 2015, due at various dates through 2048	$	2,090		$	2,083
Unsecured term bank loans, variable rates of approximately 1.37%due 2017	150			—
Pollution Control Revenue Bonds, 5% rate, due 2033	142			142
Pollution Control Revenue Bonds owned by PGE	(21		)	(21		)
Total long-term debt	2,361			2,204
Less: Unamortized debt expense	(11		)	(11		)
Less: Current portion of long-term debt	(150		)	(133		)
Long-term debt, net of current portion	$	2,200		$	2,060

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

As of December 31, 2016, the future minimum principal payments on long-term debt are as follows (in millions):

Years ending December 31:
2017	$	150
2018	—
2019	300
2020	—
2021	160
Thereafter	1,751
	$	2,361