Revenue Disaggregation of Revenue (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenues		$ 2,622	$ 2,837	$ 2,537	$ 2,740	$ 2,643	$ 2,693	$ 2,613	$ 2,581	$ 10,736	$ 10,530	$ 10,281
Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										2,885
Other non-606 revenue										54
Revenues										2,939
Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										7,075
Other non-606 revenue	[1]									722
Revenues										7,797
US and Utilities [Domain]
Disaggregation of Revenue [Line Items]
Revenues										4,230
US and Utilities [Domain] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										2,885
Other non-606 revenue										54
Revenues										2,939
US and Utilities [Domain] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										972
Other non-606 revenue	[1]									319
Revenues										1,291
South America [Member]
Disaggregation of Revenue [Line Items]
Revenues										3,533
South America [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										0
Other non-606 revenue										0
Revenues										0
South America [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										3,529
Other non-606 revenue	[1]									4
Revenues										3,533
MCAC [Member]
Disaggregation of Revenue [Line Items]
Revenues										1,728
MCAC [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										0
Other non-606 revenue										0
Revenues										0
MCAC [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										1,642
Other non-606 revenue	[1]									86
Revenues										1,728
EURASIA [Member]
Disaggregation of Revenue [Line Items]
Revenues										1,255
EURASIA [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										0
Other non-606 revenue										0
Revenues										0
EURASIA [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										943
Other non-606 revenue	[1]									312
Revenues										1,255
Corporate Other And Other Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues										(10)
Corporate Other And Other Eliminations [Member] | Regulated Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										0
Other non-606 revenue										0
Revenues										0
Corporate Other And Other Eliminations [Member] | Non-regulated revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										(11)
Other non-606 revenue	[1]									1
Revenues										$ (10)

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