Reserves for Credit Losses (Details 1) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 619			$ 619
Provisions		$ 355	$ 224	952	$ 477
Ending balance		519		519
Decrease in Card Member receivable reserves	$ (619)	(519)		(619)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Recoveries				180	184
Cumulative effect of change in accounting principle - Reserve for Credit Losses
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	$ (493)
Decrease in Card Member receivable reserves	493
Cumulative effect of change in accounting principle - Reserve for Credit Losses, adjusted balance
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	126			126	573
Provisions				952	477
Net write-offs				(557)	(426)
Other				(2)	(8)
Ending balance		519	616	519	616
Decrease in Card Member receivable reserves	$ (126)	$ (519)	$ (616)	(519)	(616)
Troubled Debt Restructuring [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs				(16)	(6)
Foreign Currency Translation Adjustments [Member]
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Other				$ (1)	$ 3