Card Member Receivables and Card Member Loans (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable segment information
Less: Reserve for losses	$ 168	$ 167	$ 183	$ 145
Card Member receivables, net	24,787	24,429
Deferred discount revenue on card member receivable	70	68
Card Member Receivables [Member]
Accounts receivable segment information
Card Member receivables	24,955	24,596
Less: Reserve for losses	168	167
Card Member receivables, net	24,787	24,429
Global Consumer Services Group [Member] | Card Member Receivables [Member]
Accounts receivable segment information
Card Member receivables	8,785	8,485
Global Commercial Services [Member] | Card Member Receivables [Member]
Accounts receivable segment information
Card Member receivables	$ 16,170	$ 16,111