Other Non-Operating Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Component of Other Expense, Nonoperating [Line Items]
Other non-operating expense	$ 49	$ 0
Innovent [Member]
Component of Other Expense, Nonoperating [Line Items]
Other non-operating expense	17
Generation Capacity (MW)	75
Fair Value	19
Carrying Amount	36
Other Nonoperating Other [Member]
Component of Other Expense, Nonoperating [Line Items]
Other non-operating expense	1
China Generation [Member]
Component of Other Expense, Nonoperating [Line Items]
Other non-operating expense	31
Fair Value	133
Carrying Amount	$ 164