Contingencies and Commitments (Details Textuals) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Total rent expense	$ 177,000,000	$ 151,000,000	$ 142,000,000
Weighted average remaining lease term	19 years
Weighted average lease discount rate	3.00%
Commitments related to agreements with certain cobrand partners	$ 4,000,000,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:CommitmentsAndContingencies
Exposure Associated with Card Member Purchases of Goods and Services [Member]
Loss Contingencies [Line Items]
Loss accrual	$ 58,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	0
Maximum [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 210,000,000