Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2013

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,
	2013			2012
Balance as of beginning of period	$	5		$	6
Provision, net	2			1
Amounts written off, less recoveries	(1		)	(1		)
Balance as of end of period	$	6		$	6

Schedule of Other Current Assets [Table Text Block]

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

	March 31, 2013		December 31, 2012
Prepaid expenses	$	51	$	37
Current deferred income tax asset	38		51
Assets from price risk management activities	11		4
Other	5		1
Other current assets	$	105	$	93

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

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

	March 31, 2013			December 31, 2012
Electric utility plant	$	6,850		$	6,811
Construction work in progress	201			140
Total cost	7,051			6,951
Less: accumulated depreciation and amortization	(2,602		)	(2,559		)
Electric utility plant, net	$	4,449		$	4,392

Accumulated depreciation and amortization in the table above includes accumulated amortization related to intangible assets of $156 million and $151 million as of March 31, 2013 and December 31, 2012, respectively.

Schedule of Regulatory Assets and Liabilities [Text Block]

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

	March 31, 2013					December 31, 2012
	Current			Noncurrent		Current			Noncurrent
Regulatory assets:
Price risk management	$	80		$	77	$	123		$	71
Pension and other postretirement plans	—			314		—			321
Deferred income taxes	—			78		—			80
Deferred broker settlements	15			1		20			1
Debt reacquisition costs	—			20		—			22
Deferred capital projects	—			19		—			16
Other	1			15		1			13
Total regulatory assets	$	96		$	524	$	144		$	524
Regulatory liabilities:
Asset retirement removal costs	$	—		$	706	$	—		$	692
Asset retirement obligations	—			40		—			39
Power cost adjustment mechanism	4			—		6			—
Other	7			36		6			34
Total regulatory liabilities	$	11	(1)	$	782	$	12	(1)	$	765

(1) 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, 2013		December 31, 2012
Accrued employee compensation and benefits	$	36	$	46
Accrued interest payable	33		23
Accrued taxes payable	30		21
Accrued dividends payable	20		21
Regulatory liabilities—current	11		12
Other	62		56
Total accrued expenses and other current liabilities	$	192	$	179

Pension and Other Postretirement Benefits Disclosure [Text Block]

Components of net periodic benefit cost are as follows (in millions):

	Three Months Ended March 31,
	Defined Benefit Pension Plan						Other Postretirement Benefits				Non-Qualified Benefit Plans
	2013			2012			2013		2012		2013		2012
Service cost	$	4		$	3		$	1	$	1	$	—	$	—
Interest cost	8			8			1		1		—		1
Expected return on plan assets	(10		)	(10		)	—		—		—		—
Amortization of net actuarial loss	6			4			—		—		—		—
Net periodic benefit cost	$	8		$	5		$	2	$	2	$	—	$	1