REGULATORY MATTERS - Capital and Capital Ratio Information (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Common Equity Tier 1 to Risk-Weighted Assets (Amount)
Actual	$ 18,574	$ 15,656
Required Minimum Capital	$ 14,633	$ 12,548
Common Equity Tier 1 to Risk-Weighted Assets (Ratio)
Actual	0.100	0.099
Required Minimum Capital	7.90%	7.90%
Tier 1 Capital to Risk-Weighted Assets (Amount)
Actual	$ 20,588	$ 17,670
Required Minimum Capital	$ 17,411	$ 14,930
Tier 1 Capital to Risk-Weighted Assets (Ratio)
Actual	0.111	0.111
Required Minimum Capital	0.094	0.094
Total Capital to Risk-Weighted Assets (Amount)
Actual	$ 23,755	$ 20,244
Required Minimum Capital	$ 21,116	$ 18,107
Total Capital to Risk-Weighted Assets (Ratio)
Actual	0.128	0.127
Required Minimum Capital	0.114	0.114
Tier 1 Capital to Average Assets (Leverage) (Amount)
Actual	$ 20,588	$ 17,670
Required Minimum Capital	$ 8,831	$ 7,272
Tier 1 Capital to Average Assets (Leverage) (Ratio)
Actual	0.093	0.097
Required Minimum Capital	0.040	0.040
Stress capital buffer	3.40%	3.40%
CBNA
Common Equity Tier 1 to Risk-Weighted Assets (Amount)
Actual	$ 20,669	$ 17,039
Required Minimum Capital	$ 12,935	$ 11,099
Common Equity Tier 1 to Risk-Weighted Assets (Ratio)
Actual	0.112	0.107
Required Minimum Capital	7.00%	7.00%
Tier 1 Capital to Risk-Weighted Assets (Amount)
Actual	$ 20,669	$ 17,039
Required Minimum Capital	$ 15,706	$ 13,477
Tier 1 Capital to Risk-Weighted Assets (Ratio)
Actual	0.112	0.107
Required Minimum Capital	0.085	0.085
Total Capital to Risk-Weighted Assets (Amount)
Actual	$ 23,534	$ 19,600
Required Minimum Capital	$ 19,402	$ 16,648
Total Capital to Risk-Weighted Assets (Ratio)
Actual	0.127	0.124
Required Minimum Capital	0.105	0.105
Tier 1 Capital to Average Assets (Leverage) (Amount)
Actual	$ 20,669	$ 17,039
Required Minimum Capital	$ 8,807	$ 7,251
Tier 1 Capital to Average Assets (Leverage) (Ratio)
Actual	0.094	0.094
Required Minimum Capital	0.040	0.040
Capital conservation buffer	2.50%	2.50%