Derivative Instruments and Hedging Activities (Derivative Instruments Not Designated for Hedge Accounting) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) from disposal and impairments of discontinued operations	$ (56)	$ (152)	$ 16
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	202	29	(149)
Net gain (loss) from disposal and impairments of discontinued operations	72	0	0
Not Designated as Hedging Instrument | Interest Rate Contract | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	(3)	(1)	(5)
Not Designated as Hedging Instrument | Interest Rate Contract | Net Equity In Earnings Of Affiliates
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	0	(6)	0
Not Designated as Hedging Instrument | Foreign Exchange Contract | Net Equity In Earnings Of Affiliates
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	(2)	(24)	0
Not Designated as Hedging Instrument | Foreign Exchange Contract | Foreign Currency Gain (Loss)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	146	64	(141)
Not Designated as Hedging Instrument | Other Contract | Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	5	11	24
Not Designated as Hedging Instrument | Other Contract | Regulated Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	0	0	(10)
Not Designated as Hedging Instrument | Other Contract | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	(3)	1	2
Not Designated as Hedging Instrument | Other Contract | Regulated Cost Of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	(6)	2	(15)
Not Designated as Hedging Instrument | Other Contract | Income (Loss) From Operations Of Discontinued Business
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Losses) Recognized in Earnings, Not Designated as Hedge Accounting	$ (7)	$ (18)	$ (4)