Debt and Borrowing Arrangements (Details 4) (USD $)	Mar. 31, 2014
Term notes, in revolving period
Debt and Borrowing Arrangements
Utilized Capacity	$ 1,500,000,000
Term notes, in revolving period | Maximum
Debt and Borrowing Arrangements
Capacity	1,500,000,000
Variable funding notes
Debt and Borrowing Arrangements
Utilized Capacity	700,000,000
Variable funding notes | Maximum
Debt and Borrowing Arrangements
Capacity	1,839,000,000
Available Capacity	1,139,000,000
Secured Canadian credit facility | Maximum
Debt and Borrowing Arrangements
Capacity	23,000,000
Available Capacity	23,000,000
Committed warehouse facilities
Debt and Borrowing Arrangements
Utilized Capacity	510,000,000
Committed warehouse facilities | Maximum
Debt and Borrowing Arrangements
Capacity	2,189,000,000
Available Capacity	1,679,000,000
Servicing advance facility
Debt and Borrowing Arrangements
Utilized Capacity	117,000,000
Servicing advance facility | Maximum
Debt and Borrowing Arrangements
Capacity	130,000,000
Available Capacity	13,000,000
Unsecured credit facilities
Debt and Borrowing Arrangements
Available capacity after applying the borrowing base coverage ratio test	26,000,000
Unsecured credit facilities | Maximum
Debt and Borrowing Arrangements
Capacity	305,000,000
Available Capacity	305,000,000
Uncommitted facilities
Debt and Borrowing Arrangements
Available Capacity	$ 2,800,000,000