Summary of Significant Accounting Policies (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2020	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Receivable reserves	$ 619		$ 573	$ 521	$ 467
Current and deferred tax	1,461		1,306
Decrease in retained earnings	$ (13,871)		$ (12,499)
Subsequent Event [Member] | ASU 2016-13 [Member]
Property, Plant and Equipment [Line Items]
Loan reserves		$ 1,700
Receivable reserves		500
Current and deferred tax		300
Decrease in retained earnings		$ 900
Minimum [Member]
Property, Plant and Equipment [Line Items]
Contract terms with large merchants	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Contract terms with large merchants	7 years
Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Premises [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Premises [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	50 years
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years