Acquisitions and Dispositions (Dispositions Narrative) (Details) $ in Millions		12 Months Ended
	Sep. 06, 2019 USD ($) asset	Dec. 31, 2019 USD ($)	[1]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of noncontrolling interest	$ 466	$ (407)
Sale of noncontrolling interest tax benefit	8
Commercial Renewables | Certain Renewable Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sales of discontinued operations and other assets, net of cash divested	$ 415
Commercial Renewables | Operating Wind, Solar And Battery Storage Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of portfolio sold	49.00%
Number of portions of portfolios sold | asset	37
Commercial Renewables | Operating Solar Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portion of portfolio sold	33.00%
Number of portions of portfolios sold | asset	11

[1] See Note 3 for additional discussion of the transaction. (f) Amounts in Retained Earnings and AOCI primarily represent impacts to accumulated other comprehensive income due to implementation of a new accounting standard related to Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.