Transactions with Affiliates 3 (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Outstanding Balance	$ 7,037	$ 13,469
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Outstanding Balance	$ 822	$ 9,292
Year-End Stated Rate on Debt	0.63%	2.76%
American Express Company [Member] | Maturity November 2023 [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Outstanding Balance	$ 454	$ 8,959
Year-End Stated Rate on Debt	0.91%	2.85%
Amex Funding Management (Europe) Limited [Member] | Maturity September 2021 [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Outstanding Balance	$ 368	$ 333
Year-End Stated Rate on Debt	0.28%	0.28%