Investments in Securities - Maturity Information (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Total Carrying Amount
Total carrying amount	$ 692
One Year or Less	1
After One Year Through Five Years	19
After Five Years Through Ten Years	36
After Ten Years	636
Total Fair Value
Total Fair Value	679	$ 696
One Year or Less	1
After One Year Through Five Years	20
After Five Years Through Ten Years	36
After Ten Years	622
Agency securities
Total Carrying Amount
Total carrying amount	435
One Year or Less	0
After One Year Through Five Years	3
After Five Years Through Ten Years	20
After Ten Years	412
Total Fair Value
Total Fair Value	414	426
One Year or Less	0
After One Year Through Five Years	3
After Five Years Through Ten Years	19
After Ten Years	392
Other mortgage-related securities
Total Carrying Amount
Total carrying amount	257
One Year or Less	1
After One Year Through Five Years	16
After Five Years Through Ten Years	16
After Ten Years	224
Total Fair Value
Total Fair Value	265	$ 270
One Year or Less	1
After One Year Through Five Years	17
After Five Years Through Ten Years	17
After Ten Years	$ 230