Derivative Instruments and Hedging Activities (Details) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended																			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				3 Months Ended				9 Months Ended		3 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended																																													3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Libor USD [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Euribor EUR [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Euribor EUR [Member] EUR (€)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Libor GBP [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Libor GBP [Member] GBP (£)	Sep. 30, 2011 Interest Rate Derivatives Current [Member] Securities Industry and Financial Markets Association Municipal Swap Index USD [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Libor USD [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Euribor EUR [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Euribor EUR [Member] EUR (€)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Libor GBP [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Libor GBP [Member] GBP (£)	Sep. 30, 2011 Interest Rate Derivatives Maximum [Member] Securities Industry and Financial Markets Association Municipal Swap Index USD [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Libor USD [Member]	Sep. 30, 2011 Interest Rate Derivatives Euribor EUR [Member]	Sep. 30, 2011 Interest Rate Derivatives Libor GBP [Member]	Sep. 30, 2011 Interest Rate Derivatives Securities Industry and Financial Markets Association Municipal Swap Index USD [Member]	Sep. 30, 2011 Interest Rate Derivatives USD ($)	Sep. 30, 2010 Interest Rate Derivatives USD ($)	Sep. 30, 2011 Interest Rate Derivatives USD ($)	Sep. 30, 2010 Interest Rate Derivatives USD ($)	Sep. 30, 2011 Interest Rate Derivatives Interest expense [Member] USD ($)	Sep. 30, 2010 Interest Rate Derivatives Interest expense [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Interest expense [Member] USD ($)	Sep. 30, 2010 Interest Rate Derivatives Interest expense [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Non-regulated revenue USD ($)	Sep. 30, 2010 Interest Rate Derivatives Non-regulated revenue USD ($)	Sep. 30, 2011 Interest Rate Derivatives Non-regulated cost of sales USD ($)	Sep. 30, 2010 Interest Rate Derivatives Non-regulated cost of sales USD ($)	Sep. 30, 2011 Interest Rate Derivatives Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2010 Interest Rate Derivatives Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2010 Interest Rate Derivatives Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2011 Interest Rate Derivatives Discontinued Operations [Member] USD ($)	Sep. 30, 2010 Interest Rate Derivatives Discontinued Operations [Member] USD ($)	Sep. 30, 2011 Cross Currency Swaps Chilean Unidad De Fomento CLF [Member] USD ($)	Sep. 30, 2011 Cross Currency Swaps Chilean Unidad De Fomento CLF [Member] CLF	Sep. 30, 2011 Cross Currency Swaps USD ($)	Sep. 30, 2010 Cross Currency Swaps USD ($)	Sep. 30, 2011 Cross Currency Swaps USD ($)	Sep. 30, 2010 Cross Currency Swaps USD ($)	Sep. 30, 2011 Cross Currency Swaps Interest expense [Member] USD ($)	Sep. 30, 2010 Cross Currency Swaps Interest expense [Member] USD ($)	Sep. 30, 2011 Cross Currency Swaps Interest expense [Member] USD ($)	Sep. 30, 2010 Cross Currency Swaps Interest expense [Member] USD ($)	Sep. 30, 2011 Cross Currency Swaps Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2010 Cross Currency Swaps Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2011 Cross Currency Swaps Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2010 Cross Currency Swaps Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2011 Foreign Currency Options Euro EUR [Member] USD ($)	Sep. 30, 2011 Foreign Currency Options Euro EUR [Member] EUR (€)	Sep. 30, 2011 Foreign Currency Options Brazilian Real BRL [Member] USD ($)	Sep. 30, 2011 Foreign Currency Options Brazilian Real BRL [Member] BRL	Sep. 30, 2011 Foreign Currency Options British Pound GBP [Member] USD ($)	Sep. 30, 2011 Foreign Currency Options British Pound GBP [Member] GBP (£)	Sep. 30, 2011 Foreign Currency Options Argentine Peso ARS [Member] USD ($)	Sep. 30, 2011 Foreign Currency Options Argentine Peso ARS [Member] ARS	Sep. 30, 2011 Foreign Currency Forwards Euro EUR [Member] USD ($)	Sep. 30, 2011 Foreign Currency Forwards Euro EUR [Member] EUR (€)	Sep. 30, 2011 Foreign Currency Forwards British Pound GBP [Member] USD ($)	Sep. 30, 2011 Foreign Currency Forwards British Pound GBP [Member] GBP (£)	Sep. 30, 2011 Foreign Currency Forwards Chilean Peso CLP [Member] USD ($)	Sep. 30, 2011 Foreign Currency Forwards Chilean Peso CLP [Member] CLP	Sep. 30, 2011 Foreign Currency Forwards Colombian Peso COP [Member] USD ($)	Sep. 30, 2011 Foreign Currency Forwards Colombian Peso COP [Member] COP	Sep. 30, 2011 Foreign Currency Forwards Argentine Peso ARS [Member] USD ($)	Sep. 30, 2011 Foreign Currency Forwards Argentine Peso ARS [Member] ARS	Sep. 30, 2011 Embedded Foreign Currency Derivatives Euro EUR [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Euro EUR [Member] EUR (€)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Brazilian Real BRL [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Brazilian Real BRL [Member] BRL	Sep. 30, 2011 Embedded Foreign Currency Derivatives Philippine Peso PHP [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Philippine Peso PHP [Member] PHP	Sep. 30, 2011 Embedded Foreign Currency Derivatives Argentine Peso ARS [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Argentine Peso ARS [Member] ARS	Sep. 30, 2011 Embedded Foreign Currency Derivatives Kazakhstani Tenge KZT [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Kazakhstani Tenge KZT [Member] KZT	Sep. 30, 2011 Embedded Foreign Currency Derivatives Hungarian Forint HUF [Member] USD ($)	Sep. 30, 2011 Embedded Foreign Currency Derivatives Hungarian Forint HUF [Member] HUF	Sep. 30, 2011 Commodity Derivatives Natural Gas MMBTU [Member] MMBTU	Sep. 30, 2011 Commodity Derivatives Petcoke Metric Tons [Member] MetricTons	Sep. 30, 2011 Commodity Derivatives Aluminum M Wh [Member] MWh	Sep. 30, 2011 Level 1 USD ($)	Dec. 31, 2010 Level 1 USD ($)	Sep. 30, 2011 Level 2 USD ($)	Dec. 31, 2010 Level 2 USD ($)	Sep. 30, 2011 Level 3 USD ($)	Dec. 31, 2010 Level 3 USD ($)	Sep. 30, 2011 Designated as Hedging Instruments USD ($)	Dec. 31, 2010 Designated as Hedging Instruments USD ($)	Sep. 30, 2011 Not Designated as Hedging Instruments USD ($)	Dec. 31, 2010 Not Designated as Hedging Instruments USD ($)	Sep. 30, 2011 Foreign Currency USD ($)	Sep. 30, 2010 Foreign Currency USD ($)	Sep. 30, 2011 Foreign Currency USD ($)	Sep. 30, 2010 Foreign Currency USD ($)	Sep. 30, 2011 Foreign Currency Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2010 Foreign Currency Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2011 Foreign Currency Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2010 Foreign Currency Foreign currency transaction gains (losses) USD ($)	Sep. 30, 2011 Foreign Currency Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2010 Foreign Currency Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2011 Foreign Currency Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2010 Foreign Currency Net Equity In Earnings Of Affiliates [Member] USD ($)	Sep. 30, 2011 Commodity & Other USD ($)	Sep. 30, 2010 Commodity & Other USD ($)	Sep. 30, 2011 Commodity & Other USD ($)	Sep. 30, 2010 Commodity & Other USD ($)	Sep. 30, 2011 Commodity & Other Non-regulated revenue USD ($)	Sep. 30, 2010 Commodity & Other Non-regulated revenue USD ($)	Sep. 30, 2011 Commodity & Other Non-regulated revenue USD ($)	Sep. 30, 2010 Commodity & Other Non-regulated revenue USD ($)	Sep. 30, 2011 Commodity & Other Non-regulated cost of sales USD ($)	Sep. 30, 2010 Commodity & Other Non-regulated cost of sales USD ($)	Sep. 30, 2011 Commodity & Other Non-regulated cost of sales USD ($)	Sep. 30, 2010 Commodity & Other Non-regulated cost of sales USD ($)	Sep. 30, 2011 Discontinued Operations [Member] USD ($)	Sep. 30, 2010 Discontinued Operations [Member] USD ($)	Sep. 30, 2011 Gener Subsidiary [Member] USD ($)
Derivative Tables [Line Items]
Notional Amount Of Interest Rate Derivatives						$ 3,511	$ 1,435	€ 1,072	$ 98	£ 63	$ 40	$ 3,585	$ 1,435	€ 1,072	$ 112	£ 72	$ 40
Weighted Average Remaining Term																		9	13	12	11																			14	14													<1	<1	<1	<1	<1	<1	<1	<1	2	2	1	1	<1	<1	<1	<1	1	1	2	2	1	1	2	2	11	11	9	9	<1	<1	11	13	8
% of Debt Currently Hedged by Index																		75.00%	66.00%	87.00%																				83.00%	83.00%
Notional Amount Of Foreign Currency Derivatives																																								237														96	67	105	173	47	29	20	88	169	123	17	11	201	98,944	44	80,376	13	61	27	20	2	4	363	15,973	215	904	207	30,606	46	10,114
Notional (CLF)																																									6
Probability Adjusted Notional																																																						82		96		40		8
Notional																																																																																				33,000,000	13,000,000	16,000,000
Current assets:
Foreign currency derivatives	52		52		7																																																																																		0	0	48	4	4	3	17	0	35	7
Commodity and other derivatives	5		5		5																																																																																		0	0	0	2	5	3	0	0	5	5
Total current assets	57		57		12																																																																																		0	0	48	6	9	6	17	0	40	12
Noncurrent assets:
Interest rate derivatives	0		0		49																																																																																		0	0	0	49	0	0	0	49	0	0
Foreign currency derivatives	54		54		31																																																																																		0	0	5	4	49	27	2	0	52	31
Cross currency derivatives	1		1		12																																																																																		0	0	0	0	1	12	1	12	0	0
Commodity and other derivatives	5		5		20																																																																																		0	0	4	4	1	16	0	0	5	20
Total noncurrent assets	60		60		112																																																																																		0	0	9	57	51	55	3	61	57	51
Total assets	117		117		124																																																																																		0	0	57	63	60	61	20	61	97	63
Current liabilities:
Interest rate derivatives	131		131		137																																																																																		0	0	102	137	29	0	126	126	5	11
Cross currency derivatives	5		5		2																																																																																		0	0	0	0	5	2	5	2	0	0
Foreign currency derivatives	7		7		13																																																																																		0	0	6	13	1	0	1	8	6	5
Commodity and other derivatives	8		8		0																																																																																		0	0	5	0	3	0	0	0	8	0
Total current liabilities	151		151		152																																																																																		0	0	113	150	38	2	132	136	19	16
Noncurrent liabilities:
Interest rate derivatives	456		456		247																																																																																		0	0	294	246	162	1	437	232	19	15
Cross currency derivatives	17		17		0																																																																																		0	0	0	0	17	0	17	0	0	0
Foreign currency derivatives	22		22		23																																																																																		0	0	11	15	11	8	0	0	22	23
Commodity and other derivatives	42		42		1																																																																																		0	0	1	0	41	1	0	0	42	1
Total noncurrent liabilities	537		537		271																																																																																		0	0	306	261	231	10	454	232	83	39
Total liabilities	688		688		423																																																																																		0	0	419	411	269	12	586	368	102	55
AOCI to be recognized in next 12 months table
Accumulated Other Comprehensive Income (Loss)																						(116)		(116)																		(1)		(1)																																																					16		16
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	(305)	(130)	(396)	(402)																		(297)	(138)	(389)	(388)																	(37)	24	(34)	(5)																																																				29	(12)	27	(5)									0	(4)	0	(4)
Gains (Losses) Reclassified from AOCL into Earnings	(65)	3	(124)	(71)																						(35)	(24)	(88)	(81)	(3)	(3)	(1)	(3)	(1)	(1)	(3)	(3)	0	(20)							(3)	0	(7)	(1)	(26)	30	(20)	16																																																3	1	(1)	1													(2)	0	(2)	0	0	(30)
Gains (Losses) Recognized in Earnings (ineffective portion)	(3)	(10)	(13)	(15)																						1	(10)	(6)	(18)					(1)	0	(2)	(1)									(3)	0	(5)	4																																																				0	0	0	0
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(25)	(12)	(9)	(31)																						(1)	(3)	(2)	(8)																																																																								27	(7)	54	(32)	0	0	0	2					(54)	1	(63)	5	3	(3)	2	2
IPL Regulatory Activity Narrative
(Increase) decrease in regulatory assets	(4)	(3)	(6)	(6)
Increase (decrease) in regulatory liabilities	(3)	(2)	3	2
Credit Risk-Related Contingent Features [Line Items]
Net liability position, derivative transactions																																																																																																																											$ 21