Nuclear Decommissioning - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Nuclear Decommissioning Additional Narrative Information [Line Items]
Increase in PPE related to ARO update	$ (335)	$ 2

Amount of asset retirement obligations (ARO) costs incurred (whether capitalized or charged to expense) during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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