Commitments and Contingencies (Schedule of Long-Term Purchase Agreements) (Parenthetical) (Detail) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Solar Affiliates [Member]
Long Term Purchase Commitment [Line Items]
Purchases from affiliates	$ 234

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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Period Type:	duration