Commitments And Contingencies (Loss Accrual) (Details) - Butte Fire [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Settlement Agreements Entered By The Utility		$ 624
Settlement Agreement Paid By The Utility		539
Loss Accrual [Member]
Loss Contingencies [Line Items]
Balance at December 31, 2016		690	$ 0
Accrued losses		350	750
Payments	[1]	(479)	(60)
Balance at December 31, 2017		$ 561	$ 690

[1] As of December 31, 2017 the Utility entered into settlement agreements in connection with the Butte fire corresponding to approximately $624 million of which $539 million has been paid by the Utility.