Loans Held-for-Investment (Past Due Loans) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Loans, Aging [Abstract]
30-59 Days Past Due	$ 10,000,000		$ 10,000,000		$ 34,000,000
60-89 Days Past Due	6,000,000		6,000,000		10,000,000
90 Days or Greater Past Due	65,000,000		65,000,000		120,000,000
Total Past Due	81,000,000		81,000,000		164,000,000
Current	5,254,000,000		5,254,000,000		4,284,000,000
Total Investment Loans	5,335,000,000		5,335,000,000		4,448,000,000
Loans greater than 90 days past due accounted for under the fair value option	7,000,000		7,000,000		5,000,000
Nonaccrual status	79,000,000	$ 120,000,000	79,000,000	$ 120,000,000	135,000,000
Accrued interest on nonaccrual loans	1,000,000	$ 2,000,000	3,000,000	$ 3,000,000
90 Days and Still Accruing	0		0		0
Residential First Mortgage
Loans, Aging [Abstract]
30-59 Days Past Due	7,000,000		7,000,000		29,000,000
60-89 Days Past Due	4,000,000		4,000,000		8,000,000
90 Days or Greater Past Due	57,000,000		57,000,000		115,000,000
Total Past Due	68,000,000		68,000,000		152,000,000
Current	2,427,000,000		2,427,000,000		2,041,000,000
Total Investment Loans	2,495,000,000		2,495,000,000		2,193,000,000
Second mortgage
Loans, Aging [Abstract]
30-59 Days Past Due	1,000,000		1,000,000		1,000,000
60-89 Days Past Due	1,000,000		1,000,000		1,000,000
90 Days or Greater Past Due	2,000,000		2,000,000		2,000,000
Total Past Due	4,000,000		4,000,000		4,000,000
Current	139,000,000		139,000,000		145,000,000
Total Investment Loans	143,000,000		143,000,000		149,000,000
HELOC commitments
Loans, Aging [Abstract]
30-59 Days Past Due	2,000,000		2,000,000		4,000,000
60-89 Days Past Due	1,000,000		1,000,000		1,000,000
90 Days or Greater Past Due	6,000,000		6,000,000		3,000,000
Total Past Due	9,000,000		9,000,000		8,000,000
Current	413,000,000		413,000,000		249,000,000
Total Investment Loans	422,000,000		422,000,000		257,000,000
Other
Loans, Aging [Abstract]
30-59 Days Past Due	0		0		0
60-89 Days Past Due	0		0		0
90 Days or Greater Past Due	0		0		0
Total Past Due	0		0		0
Current	31,000,000		31,000,000		31,000,000
Total Investment Loans	31,000,000		31,000,000		31,000,000
Consumer loans
Loans, Aging [Abstract]
30-59 Days Past Due	10,000,000		10,000,000		34,000,000
60-89 Days Past Due	6,000,000		6,000,000		10,000,000
90 Days or Greater Past Due	65,000,000		65,000,000		120,000,000
Total Past Due	81,000,000		81,000,000		164,000,000
Current	3,010,000,000		3,010,000,000		2,466,000,000
Total Investment Loans	3,091,000,000		3,091,000,000		2,630,000,000
Commercial real estate
Loans, Aging [Abstract]
30-59 Days Past Due	0		0		0
60-89 Days Past Due	0		0		0
90 Days or Greater Past Due	0		0		0
Total Past Due	0		0		0
Current	629,000,000		629,000,000		620,000,000
Total Investment Loans	629,000,000		629,000,000		620,000,000
Commercial and industrial
Loans, Aging [Abstract]
30-59 Days Past Due	0		0		0
60-89 Days Past Due	0		0		0
90 Days or Greater Past Due	0		0		0
Total Past Due	0		0		0
Current	412,000,000		412,000,000		429,000,000
Total Investment Loans	412,000,000		412,000,000		429,000,000
Warehouse lending
Loans, Aging [Abstract]
30-59 Days Past Due	0		0		0
60-89 Days Past Due	0		0		0
90 Days or Greater Past Due	0		0		0
Total Past Due	0		0		0
Current	1,203,000,000		1,203,000,000		769,000,000
Total Investment Loans	1,203,000,000		1,203,000,000		769,000,000
Commercial loans
Loans, Aging [Abstract]
30-59 Days Past Due	0		0		0
60-89 Days Past Due	0		0		0
90 Days or Greater Past Due	0		0		0
Total Past Due	0		0		0
Current	2,244,000,000		2,244,000,000		1,818,000,000
Total Investment Loans	$ 2,244,000,000		$ 2,244,000,000		$ 1,818,000,000