XML 126 R50.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Summary of Significant Accounting Policies - Operations and Maintenance (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Operating Expense [Member] |  |  |
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items] |  |  |
Results of Operations, Expense from Oil and Gas Producing Activities | $ 382 | $ 363 | $ 342

X
- Definition The amount of expenses related to oil and gas producing activities. + References No definition available. + Details
Name: | us-gaap_ResultsOfOperationsExpenseFromOilAndGasProducingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ResultsOfOperationsForOilAndGasProducingActivitiesByGeographicAreaLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_OperatingExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |