Accounts Payable and Accrued Expenses (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accounts payable and accrued expenses
Accounts payable	$ 330	$ 331
Subservicing advance liabilities	242	24
Repurchase eligible loans	88	99
Accrued payroll and benefits	70	80
Accrued interest	30	32
Other	22	20
Total	782	586
Mortgage loan unpaid principal balance	228,637	183,730
New subservicing portfolio
Accounts payable and accrued expenses
Subservicing advance liabilities	219
Servicing advance receivables	223
Mortgage loan unpaid principal balance	$ 46,800