Debt (Project Financing, Notes Payable and Others) (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term Debt		$ 10,156	$ 11,213
Russell City Project [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 341	$ 401
Debt Instrument, Interest Rate, Effective Percentage	[1]	6.50%	6.40%
Steamboat [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 384	$ 414
Debt Instrument, Interest Rate, Effective Percentage	[1]	4.50%	4.70%
OMEC [Member]
Debt Instrument [Line Items]
Long-term Debt	[2]	$ 218	$ 294
Debt Instrument, Interest Rate, Effective Percentage	[1]	7.10%	7.20%
Los Esteros Project [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 163	$ 191
Debt Instrument, Interest Rate, Effective Percentage	[1]	4.70%	5.30%
Pasadena [Member]
Debt Instrument [Line Items]
Long-term Debt	[3]	$ 76	$ 89
Debt Instrument, Interest Rate, Effective Percentage	[1]	8.90%	8.90%
Bethpage [Member]
Debt Instrument [Line Items]
Long-term Debt	[4]	$ 53	$ 60
Debt Instrument, Interest Rate, Effective Percentage	[1]	7.10%	7.10%
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 29	$ 49
Debt Instrument, Interest Rate, Effective Percentage	[1]	0.00%	0.00%
Project Financing Total [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 1,264	$ 1,498

[1] Our weighted average interest rate calculation includes the amortization of debt issuance costs and debt discount.

[2] On December 19, 2018, we refinanced the project debt associated with OMEC which lowered the aggregate debt balance to $220 million and extended the maturity to August 2024. In the event that the OMEC put option is exercised, the debt will become payable on November 3, 2019. See Note 7 for further information related to the OMEC put option.

[3] Represents a failed sale-leaseback transaction that is accounted for as financing transaction under U.S. GAAP.

[4] Represents a weighted average of first and second lien loans for the weighted average effective interest rates.