Acquisitions, Investments and Dispositions - Coram Wind (Details) - Coram Wind - California $ in Millions	1 Months Ended
Dec. 31, 2016 USD ($) MW
Business Acquisition [Line Items]
Percentage of voting interest acquired	100.00%
Generating capacity (MW AC) \| MW	102
Purchase price	$ 97
Non-utility property	191
Intangible assets	78
Restricted cash, current	8
Long-term debt	180
Net assets	$ 96

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restricted Cash, Current

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Generating Capacity

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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