Loans Held-for-Investment (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	$ 6,290	$ 6,352
Residential first mortgage loans
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	2,136	3,100
Second mortgage
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	127	135
HELOC loans
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	326	384
Other
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	30	31
Consumer loans
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	2,619	3,650
Commercial real estate
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	1,168	814
Commercial real estate | Commercial Borrower
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	252	188
Commercial and industrial
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	708	552
Warehouse lending
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	1,795	1,336
Commercial loans
Loans and Leases Receivable, Net Amount [Abstract]
Total Investment Loans	$ 3,671	$ 2,702