Regulatory Assets and Liabilities, Regulatory Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[1]	$ 95	$ 100
Regulatory Liability, Noncurrent	[1]	2,397	2,337
Other Current Liabilities
Regulatory Liabilities [Line Items]
Entity's Recorded Provision for Revenue Subject To Refund		2	0
Deferred Income Tax Adjustments and TCJA Refunds
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[2]	2	5
Regulatory Liability, Noncurrent	[2]	1,328	1,368
Plant Removal Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		651	615
Effects of regulation on employee benefit costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[3]	0	0
Regulatory Liability, Noncurrent	[3]	216	203
Renewable Resources and Environmental Initiatives
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		91	59
ITC Deferrals
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		42	40
Sales True Up and Revenue Decoupling [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		9	10
Regulatory Liability, Noncurrent		$ 41	41
Sales True Up and Revenue Decoupling [Member] | Minimum
Regulatory Liabilities [Line Items]
Regulatory Liability, Amortization Period		1 year
Sales True Up and Revenue Decoupling [Member] | Maximum
Regulatory Liabilities [Line Items]
Regulatory Liability, Amortization Period		2 years
Conservation programs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[4]	$ 34	39
Regulatory Liability, Noncurrent	[4]	0	0
Deferred Electric, Gas, and Steam Production Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		29	17
Regulatory Liability, Noncurrent		0	0
Other
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		21	29
Regulatory Liability, Noncurrent		$ 28	$ 11

[1] Revenue subject to refund of $2 million for 2021 is included in other current liabilities and none for 2020

[2] Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA.

[3] Includes regulatory amortization and certain 2018 TCJA benefits approved by the CPUC to offset the prepaid pension asset.

[4] Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.