Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Future Minimum Payments Due, Remainder of 2012	$ 42
Future Minimum Payments Due, 2013	167
Future Minimum Payments Due, 2014	165
Future Minimum Payments Due, 2015	163
Future Minimum Payments Due, 2016	159
Future Minimum Payments Due, 2017 and thereafter	478
Total minimum lease payments	$ 1,174