PARENT COMPANY FINANCIALS - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS:
Cash and due from banks	$ 1,155	$ 1,037
Other assets	8,810	8,003
TOTAL ASSETS	188,409	183,349
LIABILITIES:
Long-term borrowed funds	6,932	8,346
Other liabilities	3,425	4,166
TOTAL LIABILITIES	164,989	160,676
TOTAL STOCKHOLDERS’ EQUITY	23,420	22,673	$ 22,201	$ 20,817
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	188,409	183,349
Parent company
ASSETS:
Cash and due from banks	2,266	2,680
Other assets	140	152
TOTAL ASSETS	26,771	26,355
LIABILITIES:
Long-term borrowed funds	3,099
Other liabilities	252	241
TOTAL LIABILITIES	3,351	3,682
TOTAL STOCKHOLDERS’ EQUITY	23,420	22,673
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	26,771	26,355
Bank subsidiaries | Parent company
ASSETS:
Loans and advances	1,148	1,148
Investments in subsidiaries	22,742	22,164
Nonbank subsidiaries | Parent company
ASSETS:
Loans and advances	150	105
Investments in subsidiaries	325	106
Unaffiliated companies | Parent company
LIABILITIES:
Long-term borrowed funds	$ 3,099	$ 3,441