Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2018

Balance Sheet Components [Abstract]

SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]

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

	Years Ended December 31,
	2018			2017			2016
Balance as of beginning of year	$	6		$	6		$	6
Increase in provision	14			6			5
Amounts written off, less recoveries	(5		)	(6		)	(5		)
Balance as of end of year	$	15		$	6		$	6

Investments held in trust [Table Text Block]

The trusts are comprised of the following investments as of December 31 (in millions):  

	Nuclear     Decommissioning Trust				Non-Qualified Benefit     Plan Trust
	2018		2017		2018		2017
Cash equivalents	$	7	$	25	$	2	$	1
Marketable securities, at fair value:
Equity securities	—		—		6		7
Debt securities	35		17		1		1
Insurance contracts, at cash surrender value	—		—		27		28
	$	42	$	42	$	36	$	37

Schedule of Other Assets and Other Liabilities [Table Text Block]

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

	As of December 31,
	2018		2017
Other current assets:
Prepaid expenses	$	54	$	50
Margin deposits	16		11
Assets from price risk management activities	20		6
Other	—		6
	$	90	$	73
Accrued expenses and other current liabilities:
Regulatory liabilities—current	$	36	$	31
Accrued employee compensation and benefits	66		60
Accrued dividends payable	34		31
Accrued interest payable	27		27
Accrued taxes payable	34		31
Other	71		61
	$	268	$	241