Revenue Disaggregation of Revenue (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
Disaggregation of Revenue [Line Items]
Revenues	$ 2,560	$ 2,545	$ 2,217	$ 2,338	$ 2,431	$ 2,625	$ 2,483	$ 2,650	$ 9,660		$ 10,189		$ 10,736
Loan receivable, net of allowance of $0	$ 0				$ 1,351				0		1,351
Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									2,626		2,979		2,885
Other non-606 revenue									35		49		54
Revenues									2,661		3,028		2,939
Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									6,418		6,555		7,075
Other non-606 revenue									581	[1]	606	[1]	722
Revenues									6,999		7,161		7,797
US and Utilities [Domain]
Disaggregation of Revenue [Line Items]
Revenues									3,918		4,058		4,230
US and Utilities [Domain] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									2,626		2,979		2,885
Other non-606 revenue									35		49		54
Revenues									2,661		3,028		2,939
US and Utilities [Domain] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									1,015		767		972
Other non-606 revenue									242	[1]	263	[1]	319
Revenues									1,257		1,030		1,291
South America
Disaggregation of Revenue [Line Items]
Revenues									3,159		3,208		3,533
South America | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									0		0		0
Other non-606 revenue									0		0		0
Revenues									0		0		0
South America | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									3,151		3,205		3,529
Other non-606 revenue									8	[1]	3	[1]	4
Revenues									3,159		3,208		3,533
MCAC [Member]
Disaggregation of Revenue [Line Items]
Revenues									1,766		1,882		1,728
MCAC [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									0		0		0
Other non-606 revenue									0		0		0
Revenues									0		0		0
MCAC [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									1,668		1,788		1,642
Other non-606 revenue									98	[1]	94	[1]	86
Revenues									1,766		1,882		1,728
EURASIA [Member]
Disaggregation of Revenue [Line Items]
Revenues									828		1,047		1,255
EURASIA [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									0		0		0
Other non-606 revenue									0		0		0
Revenues									0		0		0
EURASIA [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									594		799		943
Other non-606 revenue									234	[1]	248	[1]	312
Revenues									828		1,047		1,255
Corporate Other And Other Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues									(11)		(6)		(10)
Corporate Other And Other Eliminations [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									0		0		0
Other non-606 revenue									0		0		0
Revenues									0		0		0
Corporate Other And Other Eliminations [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									(10)		(4)		(11)
Other non-606 revenue									(1)	[1]	(2)	[1]	1
Revenues									$ (11)		$ (6)		$ (10)

[1] Other non-regulated revenue primarily includes lease and derivative revenue not accounted for under ASC 606.