Loans Receivable, Net (Details - Allowance Qualitative and Quantitative Components) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Troubled Debt Restructuring [Line Items]
Quantitative component	$ 3	$ 12
Qualitative component	(1)	1
Specific valuation allowance	15	24
Total allowance for loan losses	$ 17	$ 37	$ 74	$ 221
Allowance as a % of loans receivable(2)	1.10%	1.70%
One- To Four-Family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Quantitative component	$ 2	$ 4
Qualitative component	(1)	0
Specific valuation allowance	5	5
Total allowance for loan losses	$ 6	$ 9	24	45
Allowance as a % of loans receivable(2)	0.70%	0.80%
Home Equity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Quantitative component	$ 1	$ 6
Qualitative component	0	1
Specific valuation allowance	10	19
Total allowance for loan losses	$ 11	$ 26	46	171
Allowance as a % of loans receivable(2)	1.70%	3.10%
Consumer and other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Quantitative component		$ 2
Qualitative component		0
Specific valuation allowance		0
Total allowance for loan losses	$ 0	$ 2	$ 4	$ 5
Allowance as a % of loans receivable(2)		1.00%