Commitments And Contingencies (Schedule Of Estimated Potential Funding Dates For Financing Commitments) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
July through December 2012	$ 911
2013	1,299
2014	2,490
2015	3,813
2016	3,408
Thereafter	8,346
Total	$ 20,267	$ 15,866