Loans and Card Member Receivables (Details 1) - Card Member Receivables [Member] - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 43,701	$ 57,413
Financing receivables, reserves for credit losses	267	619	$ 573	$ 521
Financing receivables, net	43,434	56,794
Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	4,296	8,284
Global Consumer Services Group [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	18,685	22,844
Global Consumer Services Group [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	0	8,300
Global Commercial Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	25,016	34,569
Global Commercial Services [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 4,300	$ 0