Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 2,700	$ 2,217	$ 5,335		$ 4,555
Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	659	610	1,357		1,313
Other non-606 revenue	12	14	21		23
Revenue	671	624	1,378		1,336
Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,868	1,419	3,691		2,870
Other non-606 revenue	161	174	266	[1]	349	[1]
Revenue	2,029	1,593	3,957		3,219
US and Utilities [Domain]
Disaggregation of Revenue [Line Items]
Revenue	972	913	1,921		1,884
US and Utilities [Domain] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	659	610	1,357		1,313
Other non-606 revenue	12	14	21		23
Revenue	671	624	1,378		1,336
US and Utilities [Domain] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	232	201	456		364
Other non-606 revenue	69	88	87	[1]	184	[1]
Revenue	301	289	543		548
MCAC [Member]
Disaggregation of Revenue [Line Items]
Revenue	490	381	1,025		813
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	465	356	975		764
Other non-606 revenue	25	25	50	[1]	49	[1]
Revenue	490	381	1,025		813
Eurasia - Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue	277	214	547		439
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	215	156	424		327
Other non-606 revenue	62	58	123	[1]	112	[1]
Revenue	277	214	547		439
Corporate Other And Other Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue	(3)	(2)	(6)		(4)
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)	(2)	(6)		(4)
Other non-606 revenue	0	0	0	[1]	0	[1]
Revenue	(3)	(2)	(6)		(4)
South American SBU
Disaggregation of Revenue [Line Items]
Revenue	964	711	1,848		1,423
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	959	708	1,842		1,419
Other non-606 revenue	5	3	6	[1]	4	[1]
Revenue	$ 964	$ 711	$ 1,848		$ 1,423

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