Commitment and Contingencies - Off Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Commercial, performance stand-by, and financial stand-by letters of credit	$ 915	$ 541
Total commitments	24,976	22,368
Total loan commitments
Other Commitments [Line Items]
Commitments	24,061	21,827
Multi-family and commercial real estate
Other Commitments [Line Items]
Commitments	52	216
One-to-four family first mortgage
Other Commitments [Line Items]
Commitments	1,694	2,066
Acquisition, development, and construction
Other Commitments [Line Items]
Commitments	3,926	3,539
Warehouse loan commitments
Other Commitments [Line Items]
Commitments	7,074	8,042
Other
Other Commitments [Line Items]
Commitments	$ 11,315	$ 7,964