Regulatory Matters and Capital Adequacy (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Regulatory Matters And Capital Adequacy
Common Equity Tier 1 required, Minimum capital ratio	0.045
Risk-based capital required, Minimum capital ratios	0.060
Minimum capital ratios	0.080
Leverage capital required, Minimum capital ratios	0.040
Parent Company | American Express Company
Regulatory capital ratios
CET1 capital	$ 20,030	$ 17,554
Tier 1 capital	21,627	19,186
Total capital	$ 24,926	$ 21,506
CET1 capital ratio	0.103	0.105
Tier 1 capital ratio	0.111	0.115
Total capital ratio	0.128	0.129
Tier 1 leverage ratio	0.099	0.105
Regulatory Matters And Capital Adequacy
Common Equity Tier 1 Required, Basel III Standards 2021	0.070
Risk-based capital required, Well-capitalized ratios	0.060
Tier 1 capital ratio, effective minimum	0.085
Well-capitalized ratios	0.100
Basel III Standards 2021	0.105
Leverage Capital Required, Basel III Standards 2020	0.040
Subsidiaries | American Express National Bank
Regulatory capital ratios
CET1 capital	$ 14,820	$ 13,085
Tier 1 capital	14,820	13,085
Total capital	$ 17,273	$ 15,283
CET1 capital ratio	0.113	0.118
Tier 1 capital ratio	0.113	0.118
Total capital ratio	0.132	0.137
Tier 1 leverage ratio	0.097	0.105
Regulatory Matters And Capital Adequacy
Common Equity Tier 1 required, Well-capitalized ratios	0.065
Common Equity Tier 1 Required, Basel III Standards 2021	0.070
Risk-based capital required, Well-capitalized ratios	0.080
Tier 1 capital ratio, effective minimum	0.085
Well-capitalized ratios	0.100
Basel III Standards 2021	0.105
Leverage capital required, Well-capitalized ratios	0.050
Leverage Capital Required, Basel III Standards 2020	0.040