Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021		Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 3,036	$ 2,545	$ 8,371		$ 7,100
Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	760	674	2,117		1,987
Other non-606 revenue	9	6	30		29
Revenue	769	680	2,147		2,016
Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	2,015	1,774	5,706		4,644
Other non-606 revenue	252	91	518	[1]	440	[1]
Revenue	2,267	1,865	6,224		5,084
US and Utilities [Domain]
Disaggregation of Revenue [Line Items]
Revenue	1,327	1,061	3,248		2,945
US and Utilities [Domain] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	760	674	2,117		1,987
Other non-606 revenue	9	6	30		29
Revenue	769	680	2,147		2,016
US and Utilities [Domain] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	394	378	850		742
Other non-606 revenue	164	3	251	[1]	187	[1]
Revenue	558	381	1,101		929
MCAC [Member]
Disaggregation of Revenue [Line Items]
Revenue	559	442	1,584		1,255
MCAC [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0		0
Other non-606 revenue	0	0	0		0
Revenue	0	0	0		0
MCAC [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	534	417	1,509		1,181
Other non-606 revenue	25	25	75	[1]	74	[1]
Revenue	559	442	1,584		1,255
Eurasia - Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue	257	195	804		634
Eurasia - Generation [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0		0
Other non-606 revenue	0	0	0		0
Revenue	0	0	0		0
Eurasia - Generation [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	197	134	621		461
Other non-606 revenue	60	61	183	[1]	173	[1]
Revenue	257	195	804		634
Corporate Other And Other Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue	(3)	(3)	(9)		(7)
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		0
Other non-606 revenue	0	0	0		0
Revenue	0	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	(3)	(3)	(9)		(7)
Other non-606 revenue	0	0	0	[1]	0	[1]
Revenue	(3)	(3)	(9)		(7)
South American SBU
Disaggregation of Revenue [Line Items]
Revenue	896	850	2,744		2,273
South American SBU | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0		0
Other non-606 revenue	0	0	0		0
Revenue	0	0	0		0
South American SBU | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	893	848	2,735		2,267
Other non-606 revenue	3	2	9	[1]	6	[1]
Revenue	$ 896	$ 850	$ 2,744		$ 2,273

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