Capacity of facility of company owned solar distribution generation facilities.

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Number of solar development projects acquired.

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Number of solar development projects sold.

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Number of wholly-owned merchant solar projects.

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

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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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.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The cash outflow from the amount invested for projects in hopes of getting a future return or interest from it.

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Acquisitions and Dispositions (Merchant Solar Projects) (Narrative) (Detail) $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2015 USD ($) Project	Sep. 30, 2015 Project MW	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Project MW	Jan. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Project Cost			$ 151	$ 405	$ 40
Merchant Solar Projects \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
MW capacity \| MW		425
Number of solar projects \| Project		24
Total number of solar projects related to potential sale \| Project	15
Amount of consideration	$ 184					$ 117
Merchant Solar Projects \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| SunEdison, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interest sold to non-controlling interest owners		33.00%
Number of Solar Development Projects in Operation [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired					100.00%
Number of Projects \| Project					7
Aggregate purchase price					$ 32
Project Cost					$ 421
MW capacity \| MW					221