Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs (Details) $ in Millions	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2018 USD ($)	Sep. 30, 2019 USD ($) project MW	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Investments Accounted for by the Equity Method
Equity investments in affiliates		$ 405		$ 412
Generation capacity (in MW) | MW		23,000
Loss on deconsolidation			$ 22
Current assets		$ 3		3
Net property, plant and equipment		73		76
Other long-term assets		28		28
Total assets		104		107
Current liabilities		1		2
Long-term debt		28		29
Other long-term liabilities		8		7
Total liabilities		37		38
Redeemable noncontrolling interest		19		19
Net assets less noncontrolling interest		48		50
Agua Caliente
Investments Accounted for by the Equity Method
Equity investments in affiliates		213
Ivampah Master Holdings LLC
Investments Accounted for by the Equity Method
Equity investments in affiliates		$ 28
Economic interest in equity method investments (as a percent)		54.50%
Number of solar electric generating projects | project		3
Generation capacity (in MW) | MW		393
Release of reserve funds	$ 95
Decrease in assets due to deconsolidation				$ 1,300
Decrease in liabilities due to deconsolidation			$ 1,200