Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2014

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Asset Retirement Obligations [Table Text Block]

AROs consist of the following (in millions):

	As of December 31,
	2014		2013
Trojan decommissioning activities	$	41	$	41
Utility plant	64		49
Non-utility property	11		10
Asset retirement obligations	$	116	$	100

Schedule of Change in Asset Retirement Obligation [Table Text Block]

The following is a summary of the changes in the Company’s AROs (in millions):

	Years Ended December 31,
	2014			2013			2012
Balance as of beginning of year	$	100		$	94		$	87
Liabilities incurred	15			4			—
Liabilities settled	(3		)	(4		)	(3		)
Accretion expense	6			6			6
Revisions in estimated cash flows	(2		)	—			4
Balance as of end of year	$	116		$	100		$	94