Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Accounts Payable and Accrued Liabilities [Abstract]
ResCap settlement accrual	$ 750	$ 750
Cash collateral received from counterparties	565	941
Accounts Payable	475	565
Derivative Liability, Fair Value, Gross Liability	406	2,468
Accrued Employee Benefits	364	494
Liability for Claims and Claims Adjustment Expense	342	341
Representation And Warranty Obligations Reserve Balance	170	105	811	825
Deferred Revenue	102	97
Other Accrued Liabilities	495	824
Accrued expenses and other liabilities	$ 3,669	$ 6,585