Segments and Geographic Information Segment and Geographic Information (Assets, Depreciation and Amortization and Capital Expenditures ) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total Assets	$ 33,648	$ 33,648	$ 32,521	$ 33,112
Depreciation and Amortization		1,045	1,003	1,169
Capital Expenditures		2,551	2,396	2,356
Interest Income		318	310	244
Interest Expense		1,050	1,056	1,170
Investments in and Advances to Affiliates	966	966	1,114	1,197
Net Equity in Earnings (Losses) of Affiliates	(175)	(172)	39	71
Operating Segments [Member] | US and Utilities SBU
Segment Reporting Information [Line Items]
Total Assets	13,334	13,334	12,286	11,548
Depreciation and Amortization		465	449	487
Capital Expenditures		1,484	1,373	905
Interest Income		18	10	5
Interest Expense		301	287	315
Investments in and Advances to Affiliates	465	465	538	535
Net Equity in Earnings (Losses) of Affiliates		11	35	41
Operating Segments [Member] | South America [Member]
Segment Reporting Information [Line Items]
Total Assets	11,314	11,314	10,941	11,126
Depreciation and Amortization		315	300	301
Capital Expenditures		692	662	477
Interest Income		95	92	95
Interest Expense		285	283	297
Investments in and Advances to Affiliates	77	77	213	358
Net Equity in Earnings (Losses) of Affiliates		(129)	15	28
Operating Segments [Member] | MCAC SBU
Segment Reporting Information [Line Items]
Total Assets	4,770	4,770	4,462	4,087
Depreciation and Amortization		183	141	122
Capital Expenditures		344	302	435
Interest Income		22	20	13
Interest Expense		142	124	111
Investments in and Advances to Affiliates	107	107	5	(5)
Net Equity in Earnings (Losses) of Affiliates		(13)	(7)	(4)
Operating Segments [Member] | EURASIA [Member]
Segment Reporting Information [Line Items]
Total Assets	3,990	3,990	4,538	6,002
Depreciation and Amortization		67	99	127
Capital Expenditures		30	51	211
Interest Income		180	186	130
Interest Expense		127	145	167
Investments in and Advances to Affiliates	215	215	293	307
Net Equity in Earnings (Losses) of Affiliates		(9)	14	9
Segment Reconciling Items [Member] | Discontinued Operations, Disposed of by Sale [Member]
Segment Reporting Information [Line Items]
Total Assets	0	0	0	86
Depreciation and Amortization		0	0	123
Capital Expenditures		0	0	315
Corporate, Non-Segment [Member] | Corporate and Other
Segment Reporting Information [Line Items]
Total Assets	240	240	294	263
Depreciation and Amortization		15	14	9
Capital Expenditures		1	8	13
Interest Income		3	2	1
Interest Expense		195	217	280
Investments in and Advances to Affiliates	$ 102	102	65	2
Net Equity in Earnings (Losses) of Affiliates		$ (32)	$ (18)	$ (3)