Credit Risk (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 loan	Dec. 31, 2013 loan
Credit Risk
Period of origination of loans within which they are sold to investors	30 days
Loan Servicing Portfolio Composition
Total servicing portfolio	$ 225,744,000,000	$ 226,837,000,000
Weighted-average interest rate (as a percent)	4.00%	4.00%
Portfolio Delinquency
Number of Loans (as a percent)	3.57%	4.34%
Unpaid Balance (as a percent)	2.79%	3.34%
Foreclosure/real estate owned
Number of Loans (as a percent)	2.44%	2.46%
Unpaid Balance (as a percent)	2.32%	2.36%
Number of loans in foreclosure	24,272	24,892
Unpaid principal balance of loans in foreclosure	4,600,000,000	4,700,000,000
30 days
Portfolio Delinquency
Number of Loans (as a percent)	1.95%	2.43%
Unpaid Balance (as a percent)	1.48%	1.82%
60 days
Portfolio Delinquency
Number of Loans (as a percent)	0.64%	0.83%
Unpaid Balance (as a percent)	0.51%	0.62%
90 or more days
Portfolio Delinquency
Number of Loans (as a percent)	0.98%	1.08%
Unpaid Balance (as a percent)	0.80%	0.90%
Conventional loans
Loan Servicing Portfolio Composition
Total servicing portfolio	191,418,000,000	191,916,000,000
Government loans
Loan Servicing Portfolio Composition
Total servicing portfolio	28,762,000,000	29,200,000,000
Home equity lines of credit
Loan Servicing Portfolio Composition
Total servicing portfolio	5,564,000,000	5,721,000,000
Owned
Loan Servicing Portfolio Composition
Total servicing portfolio	128,813,000,000	130,494,000,000
Subserviced
Loan Servicing Portfolio Composition
Total servicing portfolio	$ 96,931,000,000	$ 96,343,000,000