Other Non-Operating Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended	1 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jul. 02, 2014 Silver Ridge Power [Member]	Sep. 30, 2014 Silver Ridge Power [Member]	Sep. 30, 2014 Entek [Member] MW	Sep. 30, 2014 Entek [Member] MW
Schedule of Other Nonoperating Expense [Line Items]
Disposal Group Not Discontinued Operation Ownership Interest Sold							49.60%	49.60%
Total other non-operating expense	$ 16	$ 122	$ 60	$ 122
Generation Capacity Mega Watts							364	364
Equity Method Investment, Other than Temporary Impairment						42		18
Equity Method Investment, Purchase Price Agreement					$ 179		$ 125
CTA excluded from Impairment Expense								68