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=118942415&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=118942415&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=118942415&loc=d3e14326-108349

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

Commitments and Contingencies (Details) $ in Millions			6 Months Ended
Commitments and Contingencies (Details) $ in Millions	May 29, 2019 USD ($)	Jun. 01, 2001	Jun. 30, 2019 USD ($) facility	Aug. 18, 2016 USD ($)
Commonwealth Edison Company And Exelon Generation Company LLC
Loss Contingencies
Payment for litigation settlement	$ 26.0
CDWR and SDGE v Sunrise Power
Loss Contingencies
PPA period		10 years
Damages sought, amount			$ 1.2
Remaining term			70 months
Sierra Club Et Al V. Midwest Generation LLC
Loss Contingencies
Number of facilities \| facility			4
Lignite Contract With Texas Westmoreland Coal Co.
Loss Contingencies
Bond obligation				$ 99.0