Basis of Presentation (Details Textuals) $ in Millions			1 Months Ended	3 Months Ended	9 Months Ended
	Feb. 01, 2020 USD ($)	Jan. 01, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Apr. 20, 2020 USD ($)	Dec. 31, 2019 USD ($)		Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Ratio of combined earnings and fixed earnings to fixed charges required to maintain availability of credit line					1.25
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Decrease in Card Member receivable reserves					$ (110)			$ (162)
Shareholder’s equity			$ 2,732		2,768	$ 2,482		2,587		$ 2,396	$ 2,196
Removal of Card member receivables (U.S. consumer Card Member receivables)	$ 7,200			$ 7,200
Reduction in long term debt to affiliate	7,200
Amount borrowed from related party					2,344	305
Affiliated Entity [Member] | Restructuring of Loan Arrangements [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount borrowed from related party			7,100
Repayment of borrowings from related party			4,700
Excess deposited with AENB			2,200		1,000
Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in Card Member receivable reserves			$ (184)		(110)	$ (168)		(15)		$ (172)	$ (167)
Adoption of new accounting guidance, tax		$ 21
Shareholder’s equity		119						119	[1]
Card Member Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in Card Member loan reserves		7
Card Member Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in Card Member receivable reserves					$ (110)			$ (162)
Card Member Receivables [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in Card Member receivable reserves		$ 147
Card Member Receivables [Member] | Global Consumer Services Group [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Removal of Card member receivables (U.S. consumer Card Member receivables)	7,200
Card Member Receivables [Member] | Global Corporate Payments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Transfer of Card Member receivables	$ 5,200						$ 1,700

[1] Represents $140 million, net of tax of $21 million, related to the impact as of January 1, 2020, of adopting the new accounting guidance for the recognition of credit losses on certain financial instruments.