Basis of Presentation (Details Textuals) - USD ($) $ in Millions	Jan. 01, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Total receivable reserves decrease		$ 422		$ 619
Shareholders' equity		21,869	$ 21,062	23,071	$ 23,025	$ 23,092	$ 22,290
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Shareholders' equity		$ 12,762	$ 12,052	13,871	$ 13,652	$ 13,551	$ 12,499
Cumulative effect of change in accounting principle - Reserve for Credit Losses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total loan reserves increase	$ 1,663
Total receivable reserves decrease	(493)
Current and deferred tax impact	288
Shareholders' equity				(882)
Cumulative effect of change in accounting principle - Reserve for Credit Losses | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Shareholders' equity	$ (882)			$ (882)