Investments And Derivative Instruments (Details Textual 2) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Variable Interest Entity [Line Items]
Assets	$ 499	$ 743
Other liabilities, variable interest entity liabilities	461	394
Company's maximum exposure to the loss of the contingent capital facility	46	302
Non-Consolidated VIEs [Member]
Variable Interest Entity [Line Items]
Assets	29	32
Other liabilities, variable interest entity liabilities	27	32
Company's maximum exposure to the loss of the contingent capital facility	$ 3	$ 4