Equity (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Common Stock Value	$ 11,616,000	$ 11,616,000	$ 11,282,000
Pacific Gas And Electric Company [Member]
Common Stock Value	$ 1,322,000	$ 1,322,000	$ 1,322,000
Equity Contract [Member]
Equity Distribution Agreement, shares issued	800,000	2,200,000
Remaining equity distribution agreement amount	$ 301,000	$ 301,000
Fees and commissions	400	1,000
Stock Issued During Period Value Under Equity Distribution Agreement	$ 49,000	$ 123,000
401K Plan, DRSPP, and Shared Based Compensation Plans [Member]
Stock issued during period for stock options exercised and under 401(K) plan and DRSPP, shares		4,000,000
Stock Issued During Period Value Stock Options Exercised		$ 165,000