Regulatory Matters and Capital Adequacy (Details Textuals) $ in Billions	12 Months Ended
	Dec. 31, 2018 USD ($)
Regulatory Matters And Capital Adequacy [Abstract]
Restricted net assets of subsidiaries	$ 8.8
Amount Available for Dividend Distribution without Affecting Capital Adequacy Requirements	$ 3.9
Capital Conservation Buffer	1.875%
American Express National Bank [Member]
Regulatory Matters And Capital Adequacy [Abstract]
Dividends paid from retained earnings to its parent company	$ 5.9