Regulatory Matters - FERC Matters (Details) - Open Access Transmission Tariff - SCS	May 10, 2018
Loss Contingencies [Line Items]
Public utilities, approved return on equity percentage	10.60%
Moratorium period	5 years

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.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration