LOANS AND LEASES - Schedule of Loans Pledged as Collateral (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
FHLB of Atlanta
Pledged non-PCD loans (contractual balance)	$ 135,370	$ 133,302	$ 138,288
FHLB of Atlanta \| Non-PCD \| Asset Pledged as Collateral
FHLB of Atlanta
Lendable collateral value of pledged non-PCD loans	15,882	15,072
Less: advances	0	0
Less: letters of credit	1,450	1,450
Available borrowing capacity	14,432	13,622
Pledged non-PCD loans (contractual balance)	26,431	25,370
FRB \| Non-PCD \| Asset Pledged as Collateral
FHLB of Atlanta
Pledged non-PCD loans (contractual balance)	6,671	6,273
FRB
Lendable collateral value of pledged non-PCD loans	5,514	5,115
Less: advances	0	0
Available borrowing capacity	5,514	5,115
FDIC \| Asset Pledged as Collateral
FHLB of Atlanta
Pledged non-PCD loans (contractual balance)	48,921	51,179
FDIC
Lendable collateral value of pledged loans	48,921	51,179
Less: advances	0	0
Less: Purchase Money Note	36,072	36,072
Available borrowing capacity	$ 12,849	$ 15,107

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