The value (monetary amount) of the award the plaintiff seeks in the legal matter.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Name:	us-gaap_LossContingencyDamagesSoughtValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

COMMITMENTS AND CONTINGENCIES - Spent Nuclear Fuel Obligations - Yankee Companies (Details) - USD ($) $ in Millions	Feb. 21, 2019	May 22, 2017
Loss Contingencies [Line Items]
Remaining damages sought	$ 1.2
CYAPC, YAEC, and MYAPC
Loss Contingencies [Line Items]
Damages sought		$ 104.4
Damages awarded	103.2
CYAPC
Loss Contingencies [Line Items]
Damages awarded	40.7
YAEC
Loss Contingencies [Line Items]
Damages awarded	28.1
MYAPC
Loss Contingencies [Line Items]
Damages awarded	$ 34.4