Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Mortgage and mortgage-related assets	$ 7,547	$ 8,241
Allowance for loan losses and basis in acquired property, net	1,060	1,798
Derivative instruments	778	602
Partnership and other equity investments	88	129
Interest-only securities	3,977	2,561
Total deferred tax assets	13,450	13,331
Deferred tax liabilities:
Unrealized gains on AFS securities, net	2	20
Other, net	733	364
Total deferred tax liabilities	735	384
Deferred tax assets, net	$ 12,715	$ 12,947