Organization and Summary of Significant Accounting Policies (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Disclosure Organization And Summary Of Significant Accounting Policies [Line Items]
Consideration transferred in the merger	$ 18,000,000,000
Unbilled accounts receivable	190,000,000	157,000,000
PEC [Member]
Disclosure Organization And Summary Of Significant Accounting Policies [Line Items]
Unbilled accounts receivable	99,000,000	102,000,000
PEF [Member]
Disclosure Organization And Summary Of Significant Accounting Policies [Line Items]
Unbilled accounts receivable	$ 91,000,000	$ 55,000,000