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Disposal Group, Including Discontinued Operation, Working Capital Adjustments

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Future Capital Contributions From Partners in Equity Method Investment

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Future Revenue Rights

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Loss Contingency Number Of Projects To Be Completed

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Loss Contingency, Number of Parking Spaces Required

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Percent, after disposal, of ownership interest of a discontinued operation in which an equity method investment is retained.

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

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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Amount of gain (loss) on sale or disposal of other assets.

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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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Amount awarded to other party in judgment or settlement of litigation.

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Amount of loss contingency liability.

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The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

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Acquisitions, Discontinued Operations and Dispositions - Dispositions of Majority Interest in EVgo (Details) $ in Millions		3 Months Ended	12 Months Ended
	Jun. 17, 2016 USD ($) charging_station parking_space	Jun. 30, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale			$ (49)	$ (9)	$ 139
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| EVgo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration	$ 39
Cash received	17
Working capital adjustments	3
Capital contributions	15
Future capital contributions	7
Future earnout potential	70
Financial obligations under agreement	$ 103
Number of public fast charging Freedom stations \| charging_station	200
Number of commercial and multiifamily parking spaces \| parking_space	10,000
Loss on sale		$ 78
Loss on sale of equity interest		$ 27
Remaining obligation	$ 56		$ 6
Remaining ownership interest			23.70%