Commitments And Contingencies (Environmental Remediation Liability Composed) (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Topock natural gas compressor station	[1]	$ 300	$ 291
Hinkley natural gas compressor station	[1]	140	158
Former manufactured gas plant sites owned by the Utility or third parties		271	257
Utility-owned generation facilities (other than for fossil fuel-fired), other facilities, and third-party disposal sites		164	150
Fossil fuel-fired generation facilities and sites		94	98
Total environmental remediation liability		$ 969	$ 954

[1] See Natural Gas Compressor Station Sites below.