Debt (Project Financing, Notes Payable and Others) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term Debt		$ 11,857	$ 10,156
Debt Instrument, Interest Rate, Effective Percentage		5.80%	5.70%
Russell City Project [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 272	$ 341
Debt Instrument, Interest Rate, Effective Percentage	[1]	6.60%	6.50%
Steamboat [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 351	$ 384
Debt Instrument, Interest Rate, Effective Percentage	[1]	4.60%	4.50%
OMEC [Member]
Debt Instrument [Line Items]
Long-term Debt	[2]	$ 0	$ 218
Debt Instrument, Interest Rate, Effective Percentage	[1]	0.00%	7.10%
Los Esteros Project [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 135	$ 163
Debt Instrument, Interest Rate, Effective Percentage	[1]	5.20%	4.70%
Pasadena [Member]
Debt Instrument [Line Items]
Long-term Debt	[3]	$ 62	$ 76
Debt Instrument, Interest Rate, Effective Percentage	[1]	8.90%	8.90%
Bethpage [Member]
Debt Instrument [Line Items]
Long-term Debt	[4]	$ 45	$ 53
Debt Instrument, Interest Rate, Effective Percentage	[1]	7.00%	7.10%
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 14	$ 29
Debt Instrument, Interest Rate, Effective Percentage	[1]	0.00%	0.00%
Project Financing Total [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 879	$ 1,264

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

[2] On August 14, 2019, we repaid the project debt associated with OMEC from a portion of the proceeds received from the issuance of our 2026 First Lien Term Loans (as discussed above), together with cash on hand.

[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.