Commitments And Contingencies (Environmental Remediation Liability Composed) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Topock natural gas compressor station	[1]	$ 310	$ 299
Hinkley natural gas compressor station	[1]	147	135
Former manufactured gas plant sites owned by the Utility or third parties		306	285
Utility-owned generation facilities (other than for fossil fuel-fired), other facilities, and third-party disposal sites		124	131
Fossil fuel-fired generation facilities and sites		131	108
Total environmental remediation liability		$ 1,018	$ 958

[1] See "Natural Gas Compressor Station Sites" below.