Borrowings - Detailed Information on FHLB Advances and Other Borrowings (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt Disclosure [Abstract]
Maximum outstanding at any month end	$ 2,200	$ 4,737
Average outstanding balance	1,918	3,979
Average remaining borrowing capacity	$ 4,451	$ 5,484
Weighted average interest rate	0.72%	0.43%