Revenue (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue		$ 2,338	$ 2,650
Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		703	778
Other non-606 revenue		9	7
Revenue		712	785
Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		1,451	1,712
Other non-606 revenue	[1]	175	153
Revenue		1,626	1,865
US and Utilities [Domain]
Disaggregation of Revenue [Line Items]
Revenue		971	1,019
US and Utilities [Domain] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		703	778
Other non-606 revenue		9	7
Revenue		712	785
US and Utilities [Domain] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		163	173
Other non-606 revenue	[1]	96	61
Revenue		259	234
South America [Member]
Disaggregation of Revenue [Line Items]
Revenue		712	845
South America [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0	0
Other non-606 revenue		0	0
Revenue		0	0
South America [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		711	843
Other non-606 revenue	[1]	1	2
Revenue		712	845
MCAC [Member]
Disaggregation of Revenue [Line Items]
Revenue		432	450
MCAC [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0	0
Other non-606 revenue		0	0
Revenue		0	0
MCAC [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		408	429
Other non-606 revenue	[1]	24	21
Revenue		432	450
Eurasia - Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue		225	339
Eurasia - Generation [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0	0
Other non-606 revenue		0	0
Revenue		0	0
Eurasia - Generation [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		171	267
Other non-606 revenue	[1]	54	72
Revenue		225	339
Corporate Other And Other Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue		(2)	(3)
Corporate Other And Other Eliminations [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0	0
Other non-606 revenue		0	0
Revenue		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		(2)	0
Other non-606 revenue	[1]	0	(3)
Revenue		$ (2)	$ (3)

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