Other Non-operating Expense Other Non-operating Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Nonoperating Expense	$ 122	$ 0	$ 122	$ 50
Elsta [Member]
Other Nonoperating Expense	122	0	122	0
Generation capacity mega watts	630		630
Assets Carrying Amount Disclosure Nonrecurring	240		240
Assets, fair value	118		118
China Generation [Member]
Other Nonoperating Expense	0	0	0	32
Innovent [Member]
Other Nonoperating Expense	0	0	0	17
Other Nonoperating Other [Member]
Other Nonoperating Expense	$ 0	$ 0	$ 0	$ 1