Employee Benefit Plans (Reconciliation Of Changes In Plan Assets Benefit Obligations And Funded Status) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liability		$ (2,128)		$ (2,641)
Decrease in other comprehensive income		(1)		2	$ 1
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1		2,173		2,035
Actual return on plan assets		298		167
Company contributions		33		52
Plan participant contribution		87		85
Benefits and expenses paid		(171)		(166)
Fair value of plan assets at December 31		2,420		2,173	2,035
Projected benefit obligation at January 1		1,877		1,766
Service cost for benefits earned		59		52
Interest cost		77		76	71
Actuarial (gain) loss		(49)		11
Plan amendments		0		37
Benefits and expenses paid		(157)		(153)
Federal subsidy on benefits paid		3		3
Projected benefit obligation at December 31		1,897		1,877	1,766
Noncurrent liability		(30)		(72)
Net assets (liabilities) at end of year		523		296
Noncurrent asset	[1]	553		368
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1		14,729		13,745
Actual return on plan assets		2,380		1,358
Company contributions		335		334
Benefits and expenses paid		(792)		(708)
Fair value of plan assets at December 31		16,652		14,729	13,745
Projected benefit obligation at January 1		17,305		16,299
Service cost for benefits earned		472		453
Interest cost		714		715	673
Actuarial (gain) loss		1,048		637
Plan amendments		10		(91)
Benefits and expenses paid		(792)		(708)
Projected benefit obligation at December 31		18,757	[2]	17,305	$ 16,299
Current liability		(7)		(7)
Noncurrent liability		(2,098)		(2,569)
Net assets (liabilities) at end of year		$ (2,105)		$ (2,576)

[1] At December 31, 2017 and 2016, the postretirement medical plan was in an overfunded position and the postretirement life insurance plan was in an underfunded position.

[2] PG&E Corporation’s accumulated benefit obligation was $16.8 billion and $15.6 billion at December 31, 2017 and 2016, respectively.