Derivative Instruments and Hedging Activities - Part 1 (Details) In Millions, unless otherwise specified	3 Months Ended																3 Months Ended										3 Months Ended
	Mar. 31, 2015 Interest rate derivatives [Member] Libor USD [Member]		Mar. 31, 2015 Interest rate derivatives [Member] Euribor EUR [Member]		Mar. 31, 2015 Interest rate derivatives [Member] Maximum [Member] Libor USD [Member] USD ($)		Mar. 31, 2015 Interest rate derivatives [Member] Maximum [Member] Euribor EUR [Member] USD ($)		Mar. 31, 2015 Interest rate derivatives [Member] Maximum [Member] Euribor EUR [Member] EUR (€)		Mar. 31, 2015 Interest rate derivatives [Member] Current Notional [Member] Libor USD [Member] USD ($)		Mar. 31, 2015 Interest rate derivatives [Member] Current Notional [Member] Euribor EUR [Member] USD ($)		Mar. 31, 2015 Interest rate derivatives [Member] Current Notional [Member] Euribor EUR [Member] EUR (€)		Mar. 31, 2015 Cross currency derivatives [Member] Chilean Unidad De Fomento CLF [Member]		Mar. 31, 2015 Cross currency derivatives [Member] Maximum [Member] Chilean Unidad De Fomento CLF [Member] USD ($)		Mar. 31, 2015 Cross currency derivatives [Member] Maximum [Member] Chilean Unidad De Fomento CLF [Member] CLF		Mar. 31, 2015 Cross currency derivatives [Member] Current Notional [Member] Chilean Unidad De Fomento CLF [Member] USD ($)		Mar. 31, 2015 Cross currency derivatives [Member] Current Notional [Member] Chilean Unidad De Fomento CLF [Member] CLF		Mar. 31, 2015 Foreign Currency Options [ Member] Chilean Unidad De Fomento CLF [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Chilean Unidad De Fomento CLF [Member] CLF		Mar. 31, 2015 Foreign Currency Options [ Member] Chilean Peso CLP [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Chilean Peso CLP [Member] CLP		Mar. 31, 2015 Foreign Currency Options [ Member] Brazilian Real BRL [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Brazilian Real BRL [Member] BRL		Mar. 31, 2015 Foreign Currency Options [ Member] Euro EUR [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Euro EUR [Member] EUR (€)		Mar. 31, 2015 Foreign Currency Options [ Member] Colombian Peso COP [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Colombian Peso COP [Member] COP		Mar. 31, 2015 Foreign Currency Options [ Member] Argentine Peso ARS [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] Argentine Peso ARS [Member] COP		Mar. 31, 2015 Foreign Currency Options [ Member] British Pound GBP [Member] USD ($)		Mar. 31, 2015 Foreign Currency Options [ Member] British Pound GBP [Member] GBP (£)		Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] Brazilian Real BRL [Member] USD ($)		Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] Brazilian Real BRL [Member] BRL		Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] Argentine Peso ARS [Member]		Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] British Pound GBP [Member]	Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] Kazakhstani Tenge KZT [Member] USD ($)		Mar. 31, 2015 Embedded Foreign Currency Derivatives [Member] Kazakhstani Tenge KZT [Member] KZT		Mar. 31, 2015 Commodity Contract [Member] Power MWh [Member] MWh		Mar. 31, 2015 Commodity Contract [Member] Coal Metric Tons [Member] T
Derivative Tables [Line Items]
Derivatives, notional amount					$ 3,010	[1]	$ 564	[1]	€ 526	[1]	$ 2,422	[1]	$ 564	[1]	€ 526	[1]			$ 173	[1]	4	[1]	$ 173	[1]	4	[1]	$ 360		9	[2]	$ 197		122,874	[2]	$ 30		95	[2]	$ 50		€ 47	[2]	$ 51		128,436	[2]	$ 227		2,001	[2]	$ 16		£ 11	[2]	$ 29		93	[2]				$ 23		4,278	[2]
Weighted Average Remaining Term (less than 1 for Chilean Peso, Brazilian Real, Euro, Colombian Peso, British Pound, and Philippine Peso)	11 years	[1]	7 years	[1]													14 years	[1]													1 year		1 year		1 year		1 year		1 year		1 year		1 year		1 year		10 years		10 years		1 year		1 year							[3]	1 year	1 year	[3]	1 year	[3]	2 years	[4]	2 years	[4]
Weighted Average Remaining Term (string type)																											<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]	10	[3]	10	[3]	<1	[3]	<1	[3]	<1	[3]	<1	[3]
% of Debt Currently Hedged by Index	51.00%	[1],[5]	87.00%	[1],[5]													82.00%	[1],[5]
Notional (MWh)																																																																		8,000,000		1,000,000

[1] The Company’s interest rate derivative instruments primarily include accreting and amortizing notionals. The maximum derivative notional represents the largest notional at any point between March 31, 2015 and the maturity of the derivative instrument, which includes forward-starting derivative instruments. The interest rate and cross-currency derivatives range in maturity through 2033 and 2028, respectively.

[2] Represents contractual notionals. The notionals for options have not been probability adjusted, which generally would decrease them.

[3] Represents the remaining tenor of our foreign currency derivatives weighted by the corresponding notional. These options and forwards and these embedded derivatives range in maturity through 2025 and 2017, respectively.

[4] Represents the remaining tenor of our commodity derivatives weighted by the corresponding volume. These derivatives range in maturity through 2016.

[5] The percentage of variable-rate debt currently hedged is based on the related index and excludes forecasted issuances of debt and variable-rate debt tied to other indices where the Company has no interest rate derivatives.