Commitments and Contingencies (Nuclear Insurance) (Narrative) (Detail) - USD ($)	1 Months Ended
Mar. 31, 2021	Feb. 28, 2021
Nuclear Obligations \| Secondary Financial Protection Program
Loss Contingencies [Line Items]
Maximum liability protection per nuclear incident amount	$ 13,700,000,000	$ 13,800,000,000

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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