Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2017

Balance Sheet Components [Abstract]

Schedule of Other Current Assets [Table Text Block]

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

	September 30, 2017		December 31, 2016
Prepaid expenses	$	27	$	48
Assets from price risk management activities	4		18
Margin deposits	4		8
Other	8		3
Other current assets	$	43	$	77

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

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

	September 30, 2017			December 31, 2016
Electric utility plant	$	9,766		$	9,534
Construction work-in-progress	386			213
Total cost	10,152			9,747
Less: accumulated depreciation and amortization	(3,514		)	(3,313		)
Electric utility plant, net	$	6,638		$	6,434

Schedule of Regulatory Assets and Liabilities [Text Block]

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

	September 30, 2017					December 31, 2016
	Current			Noncurrent		Current			Noncurrent
Regulatory assets:
Price risk management	$	39		$	150	$	26		$	120
Pension and other postretirement plans	—			225		—			235
Deferred income taxes	—			83		—			86
Debt issuance costs	—			20		—			22
Other	3			48		10			35
Total regulatory assets	$	42		$	526	$	36		$	498
Regulatory liabilities:
Asset retirement removal costs	$	—		$	921	$	—		$	887
Trojan decommissioning activities	4			—		18			—
Asset retirement obligations	—			52		—			49
Other	16			29		33			22
Total regulatory liabilities	$	20	*	$	1,002	$	51	*	$	958

* 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):

	September 30, 2017		December 31, 2016
Accrued employee compensation and benefits	$	51	$	52
Accrued taxes payable	46		25
Accrued interest payable	40		25
Accrued dividends payable	31		30
Regulatory liabilities—current	20		51
Other	60		71
Total accrued expenses and other current liabilities	$	248	$	254

Pension and Other Postretirement Benefits Disclosure [Text Block]

Components of net periodic benefit cost under the defined benefit pension plan are as follows (in millions):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
Service cost	$	4		$	4		$	12		$	12
Interest cost	8			9			25			25
Expected return on plan assets	(10		)	(10		)	(30		)	(30		)
Amortization of net actuarial loss	3			3			9			11
Net periodic benefit cost	$	5		$	6		$	16		$	18