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Regulatory Assets and Liabilities, Regulatory Liabilities (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [1] | $ 436 | $ 239
Regulatory Liability, Noncurrent | [1] | 5,187 | 5,083
Deferred Income Tax Adjustment and TCJA Refunds |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [2] | 157 | 0
Regulatory Liability, Noncurrent | [2] | $ 3,715 | 3,790
Regulatory liability, remaining amortization period |  | Various |
Plant Removal Costs |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current |  | $ 0 | 0
Regulatory Liability, Noncurrent |  | $ 1,175 | 1,131
Regulatory liability, remaining amortization period |  | Plant lives |
Effects of regulation on employee benefit costs |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [3] | $ 0 | 0
Regulatory Liability, Noncurrent | [3] | $ 137 | 46
Regulatory liability, remaining amortization period |  | Various |
Renewable Resources and Environmental Initiatives |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current |  | $ 9 | 19
Regulatory Liability, Noncurrent |  | $ 54 | 60
Regulatory liability, remaining amortization period |  | Various |
Investment Tax Credit Deferrals |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [4] | $ 0 | 0
Regulatory Liability, Noncurrent | [4] | $ 40 | 23
Regulatory liability, remaining amortization period |  | Various |
Deferred Electric, Natural Gas and Steam Production Costs |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current |  | $ 102 | 104
Regulatory Liability, Noncurrent |  | $ 0 | 0
Regulatory liability remaining amortization period, maximum |  | 1 year |
Contract Valuation Adjustments |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [5] | $ 26 | 30
Regulatory Liability, Noncurrent | [5] | $ 0 | 0
Regulatory liability remaining amortization period, maximum |  | 1 year |
Conservation Programs |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current | [6] | $ 36 | 23
Regulatory Liability, Noncurrent | [6] | $ 0 | 0
Regulatory liability remaining amortization period, maximum |  | 1 year |
DOE Settlement |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current |  | $ 19 | 18
Regulatory Liability, Noncurrent |  | $ 0 | 0
Regulatory liability remaining amortization period, maximum |  | 1 year |
Other Regulatory Liabilities |  |  |
Regulatory Liabilities [Line Items] |  |  |
Regulatory Liability, Current |  | $ 87 | 45
Regulatory Liability, Noncurrent |  | $ 66 | 33
Regulatory liability, remaining amortization period |  | Various |
Other Current Liabilities |  |  |
Regulatory Liabilities [Line Items] |  |  |
Entity's Recorded Provision for Revenue Subject To Refund |  | $ 29 | $ 15
[1] | Revenue subject to refund of $29 million and $15 million for 2018 and 2017, respectively, is included in other current liabilities.
[2] | Includes the revaluation of recoverable/regulated plant ADIT and revaluation impact of non-plant ADIT due to the TCJA.
[3] | Includes regulatory amortization and certain TCJA benefits approved by the CPUC to offset the PSCo prepaid pension asset at Dec. 31, 2018.
[4] | Includes impact of lower federal tax rate due to the TCJA.
[5] | Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases.
[6] | Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

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- Definition The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 405 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
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