VARIABLE INTEREST ENTITIES - POWER PURCHASE AGREEMENT (Details) - Power purchase agreement $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($) MW
Variable interest entities
Firm capacity from power purchase agreement (in megawatts) \| MW	236
Minimum energy requirements over remaining term of power purchase agreement (in megawatts) \| MW	0
Remaining term of power purchase agreement (in years)	1 year
Residual guarantee associated with power purchase agreement \| $	$ 0.0
Required capacity payments over remaining term of power purchase agreement \| $	$ 8.9

Under long-term contracts with public utility districts, cooperatives or other organizations, a utility company receives a portion of the output of a production plant constructed and financed by the district or cooperative. The utility has only a nominal or no investment at all in the plant but pays a proportionate part of the plant's costs, including debt service.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.D)
-URI http://asc.fasb.org/extlink&oid=6499423&loc=d3e659339-123030

+ Details

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- 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.

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- Definition

Firm capacity, in megawatts, from a power purchase agreement accounted for as a finance lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	wep_
Data Type:	num:powerItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum energy requirements, in megawatts, over the remaining term of a power purchase agreement accounted for as a finance lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	wep_
Data Type:	num:powerItemType
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- Definition

The remaining term, in years, of a power purchase agreement accounted for as a finance lease.

+ References

No definition available.

+ Details

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- Definition

Amount of the residual guarantee associated with a power purchase agreement accounted for as a finance lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	wep_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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