Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Mortgage and mortgage-related assets	$ 9,290	$ 9,285
Allowance for loan losses and basis in acquired property, net	1,240	2,065
Debt and derivative instruments	627	687
Partnership credits	0	161
Partnership and other equity investments	152	223
Deferred Tax Assets, Investments	788	738
Other, net	0	102
Total deferred tax assets	12,097	13,261
Deferred tax liabilities:
Unrealized gains on AFS securities, net	26	73
Deferred Tax Liabilities, Other	161	0
Total deferred tax liabilities	187	73
Net deferred tax assets	$ 11,910	$ 13,188