Loan Receivables (Schedule of Loans That Entered a Modification Program During the Period) (Details) $ in Millions		12 Months Ended
		Dec. 31, 2020 USD ($) accounts	Dec. 31, 2019 USD ($) accounts	Dec. 31, 2018 USD ($) accounts
Credit Card Loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Accounts that entered a loan modification program during the period, number of accounts | accounts	[1]	152,055	368,009	268,817
Accounts that entered a loan modification program during the period, balances	[1]	$ 1,022	$ 2,364	$ 1,713
Financing Receivables Modifications Entering Program, Converted from Revolving Line-of-Credit Arrangement to Term Loan		$ 670	$ 741	$ 491
Total Other Loans [Member] | Private Student Loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Accounts that entered a loan modification program during the period, number of accounts | accounts		1,916	6,742	4,057
Accounts that entered a loan modification program during the period, balances		$ 35	$ 124	$ 74
Total Other Loans [Member] | Personal Loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Accounts that entered a loan modification program during the period, number of accounts | accounts		8,805	10,945	8,260
Accounts that entered a loan modification program during the period, balances		$ 114	$ 147	$ 111

[1] Accounts that entered a credit card TDR program include $670 million, $741 million and $491 million that were converted from revolving line-of-credit arrangements to term loans during the years ended December 31, 2020, 2019 and 2018, respectively.