Segments and Geographic Information Segment and Geographic Information (Revenue and Assets by Country) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		$ 2,560	$ 2,545	$ 2,217	$ 2,338	$ 2,431	$ 2,625	$ 2,483	$ 2,650	$ 9,660	$ 10,189	$ 10,736
Property, plant and equipment, net		22,826				22,574				22,826	22,574
Long-Lived Assets		23,103				22,822				23,103	22,822
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	[1]									3,243	3,230	3,462
Long-Lived Assets	[1]	10,360				9,762				10,360	9,762
Total Non-U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										6,417	6,959	7,274
Long-Lived Assets		12,743				13,060				12,743	13,060
VIET NAM
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	[2]									285	343	245
Long-Lived Assets	[2]	0				2				0	2
PHILIPPINES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	[3]									0	0	93
Long-Lived Assets	[3]	0				0				0	0
Brazil
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										401	525	527
Long-Lived Assets		1,091				1,266				1,091	1,266
CHILE
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										2,092	1,839	2,087
Long-Lived Assets		5,831				5,982				5,831	5,982
Dominican Republic
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										896	877	884
Long-Lived Assets		843				1,006				843	1,006
El Salvador
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										666	824	768
Long-Lived Assets		361				351				361	351
Colombia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										358	472	428
Long-Lived Assets		355				340				355	340
ARGENTINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										308	373	487
Long-Lived Assets		484				393				484	393
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										349	402	399
Long-Lived Assets		623				649				623	649
UNITED KINGDOM
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										0	147	390
Long-Lived Assets		0				0				0	0
BULGARIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										444	459	426
Long-Lived Assets		1,149				1,106				1,149	1,106
Panama
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										519	601	438
Long-Lived Assets		1,939				1,945				1,939	1,945
Puerto Rico
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	[1]									298	294	257
Long-Lived Assets	[1]	533				538				533	538
JORDAN
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										96	95	95
Long-Lived Assets		44				0				44	0
Other Non-U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue										3	2	$ 7
Long-Lived Assets		$ 23				$ 20				$ 23	$ 20

[1] Includes Puerto Rico revenues of $298 million, $294 million, and $257 million for the years ended December 31, 2020, 2019, and 2018, respectively, and long-lived assets of $533 million and $538 million as of December 31, 2020 and 2019, respectively.

[2] The Mong Duong 2 power project is operated under a BOT contract. Future expected payments for the construction performance obligation are recognized in Loan receivable on the Consolidated Balance Sheets as of December 31, 2019. Mong Duong assets were classified as held-for-sale as of December 31, 2020. See Notes 20—Revenue and 25—Held-For-Sale and Dispositions for further information.

[3] The Masinloc long-lived assets were deconsolidated upon completion of the sale in March 2018. See Note 25—Held-For-Sale and Dispositions for further information.