Transactions with Affiliates 1 (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Loans to affiliates and other	$ 14,136	$ 14,527	$ 10,659
American Express Company [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	0	961
American Express Services Europe Limited [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	3,552	2,747
Amex Bank Of Canada [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	1,334	1,737
American Express Australia Limited [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	1,839	1,616
American Express Company (Mexico) S.A. de C.V. [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	463	812
American Express Bank (Mexico) S.A. [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	348	325
American Express International, Inc. [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	1,243	1,180
American Express Saudi Arabia (C) JSC [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	53	34
Alpha Card S.C.R.L./C.V.B.A [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	114	138
American Express International (NZ), Inc. [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	72	80
American Express Limited [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	3,847	3,847
Amex Global Holdings CV [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	888	888
Amex Funding Management (Europe) Limited [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	0	38
American Express International, Inc. - Branch - Singapore [Member]
Related Party Transaction [Line Items]
Loans to affiliates and other	$ 383	$ 124