Derivative Instruments and Hedging Activities - Part 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	$ (16)	$ 25
Gains (Losses) Reclassified from AOCL into Earnings	(31)	(114)
Gains (Losses) Recognized in Earnings (ineffective portion)	(1)	(1)
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(25)	(31)
Interest Rate Derivatives
AOCI to be recognized in next 12 months table
Accumulated Other Comprehensive Income Loss Before Tax Expected Increase Decrease Next Twelve Months	(146)
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	(13)	11
Interest Rate Derivatives | Interest Expense [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	(32)	(32)
Gains (Losses) Recognized in Earnings (ineffective portion)	(1)	(1)
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	1	(2)
Interest Rate Derivatives | Non-regulated cost of sales
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	(1)	(2)
Interest Rate Derivatives | Net Equity In Earnings Of Affiliates [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	(2)	(1)
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(6)	0
Interest Rate Derivatives | Gain on sale of investments [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	0	(92)
Cross Currency Swaps
AOCI to be recognized in next 12 months table
Accumulated Other Comprehensive Income Loss Before Tax Expected Increase Decrease Next Twelve Months	(11)
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	1	14
Cross Currency Swaps | Interest Expense [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	(3)	(3)
Cross Currency Swaps | Foreign currency transaction gains (losses) [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	5	18
Foreign Currency
AOCI to be recognized in next 12 months table
Accumulated Other Comprehensive Income Loss Before Tax Expected Increase Decrease Next Twelve Months	(6)
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	1	6
Foreign Currency | Foreign currency transaction gains (losses) [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	2	0
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	6	(38)
Foreign Currency | Net Equity In Earnings Of Affiliates [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(3)	0
Commodity & Other
AOCI to be recognized in next 12 months table
Accumulated Other Comprehensive Income Loss Before Tax Expected Increase Decrease Next Twelve Months	(9)
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in AOCL	(5)	(6)
Commodity & Other | Non-regulated revenue
Gain Loss By Type Of Derivative Tables
Gains (Losses) Reclassified from AOCL into Earnings	0	(2)
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(21)	14
Commodity & Other | Non-regulated cost of sales
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	1	3
Commodity & Other | Regulated Revenue [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	(3)	(4)
Commodity & Other | Regulated Cost Of Sales [Member]
Gain Loss By Type Of Derivative Tables
Gains (Losses) Recognized in Earnings (not designated as hedging instruments)	$ 0	$ (4)