Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2015

Balance Sheet Components [Abstract]

Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]

The activity in the allowance for uncollectible accounts is as follows (in millions):

	Three Months Ended March 31,
	2015			2014
Balance as of beginning of period	$	6		$	6
Provision, net	2			2
Amounts written off, less recoveries	(1		)	(1		)
Balance as of end of period	$	7		$	7

Schedule of Other Current Assets [Table Text Block]

Other current assets consist of the following (in millions):

	March 31, 2015		December 31, 2014
Prepaid expenses	$	58	$	39
Current deferred income tax asset	33		33
Margin deposits	20		11
Accrued sales tax refund related to Tucannon River Wind Farm	11		23
Assets from price risk management activities	7		6
Other	4		3
Other current assets	$	133	$	115

Schedule of Public Utility Property, Plant, and Equipment [Table Text Block]

Electric utility plant, net consists of the following (in millions):

	March 31, 2015			December 31, 2014
Electric utility plant	$	8,251		$	8,161
Construction work-in-progress	478			417
Total cost	8,729			8,578
Less: accumulated depreciation and amortization	(2,940		)	(2,899		)
Electric utility plant, net	$	5,789		$	5,679

Schedule of Regulatory Assets and Liabilities [Text Block]

Regulatory assets and liabilities consist of the following (in millions):

	March 31, 2015					December 31, 2014
	Current			Noncurrent		Current			Noncurrent
Regulatory assets:
Price risk management	$	100		$	174	$	100		$	121
Pension and other postretirement plans	—			242		—			247
Deferred income taxes	—			87		—			86
Debt issuance costs	—			15		—			15
Deferred capital projects	14			—		19			—
Other	11			27		14			25
Total regulatory assets	$	125		$	545	$	133		$	494
Regulatory liabilities:
Asset retirement removal costs	$	—		$	813	$	—		$	804
Trojan decommissioning activities	22			29		23			34
Asset retirement obligations	—			40		—			39
Other	37			29		37			29
Total regulatory liabilities	$	59	*	$	911	$	60	*	$	906

* Included in Accrued expenses and other current liabilities in the condensed consolidated balance sheets.

Other Liabilities Disclosure [Text Block]

Accrued expenses and other current liabilities consist of the following (in millions):

	March 31, 2015		December 31, 2014
Regulatory liabilities—current	$	59	$	60
Accrued employee compensation and benefits	39		51
Accrued interest payable	40		26
Accrued dividends payable	22		23
Accrued taxes payable	26		22
Other	57		54
Total accrued expenses and other current liabilities	$	243	$	236

Pension and Other Postretirement Benefits Disclosure [Text Block]

Components of net periodic benefit cost are as follows for the three months ended March 31 (in millions):

	Defined Benefit Pension Plan						Other Postretirement Benefits
	2015			2014			2015		2014
Service cost	$	4		$	4		$	1	$	—
Interest cost	8			9			1		1
Expected return on plan assets	(10		)	(10		)	—		—
Amortization of net actuarial loss	5			4			—		—
Net periodic benefit cost	$	7		$	7		$	2	$	1