Loan Receivables (Schedule of Delinquent and Non-Accruing Loans) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent $ 506   $ 583
Loan receivables, 90 or more days delinquent 500   517
Loan receivables, total past due 1,006   1,100
Loan receivables, 90 or more days delinquent and accruing 451   477
Loan receivables, total non-accruing 196   183
Credit Card Loans [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent 421   491
Loan receivables, 90 or more days delinquent 458   480
Loan receivables, total past due 879   971
Loan receivables, 90 or more days delinquent and accruing 411 [1]   442 [1]
Loan receivables, total non-accruing 167 [2]   157 [2]
Estimated gross interest income that would have been recorded based on original terms 7 7  
Credit Card Loans [Member] | Internal And External Loan Modification Programs [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 90 or more days delinquent and accruing 43   43
Total Other Loans [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent 85   92
Loan receivables, 90 or more days delinquent 42   37
Loan receivables, total past due 127   129
Loan receivables, 90 or more days delinquent and accruing 40   35
Loan receivables, total non-accruing 29   26
Total Other Loans [Member] | Personal Loans [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent 28   29
Loan receivables, 90 or more days delinquent 11   11
Loan receivables, total past due 39   40
Loan receivables, 90 or more days delinquent and accruing 10 [3]   10 [3]
Loan receivables, total non-accruing 6   5
Total Other Loans [Member] | Personal Loans [Member] | Internal And External Loan Modification Programs [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 90 or more days delinquent and accruing 3   3
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent 56   62
Loan receivables, 90 or more days delinquent 30   25
Loan receivables, total past due 86   87
Loan receivables, 90 or more days delinquent and accruing 30 [4]   25 [4]
Loan receivables, total non-accruing 0   0
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | Entity Loan Modification Program [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 90 or more days delinquent and accruing 5   5
Total Other Loans [Member] | Other Loans [Member]      
Financing Receivable, Recorded Investment, Past Due [Line Items]      
Loan receivables, 30 to 89 days delinquent 1   1
Loan receivables, 90 or more days delinquent 1   1
Loan receivables, total past due 2   2
Loan receivables, 90 or more days delinquent and accruing 0   0
Loan receivables, total non-accruing $ 23   $ 21
[1] Credit card loans that are 90 or more days delinquent and accruing interest include $43 million of loans accounted for as troubled debt restructurings at March 31, 2015 and December 31, 2014.
[2] The Company estimates that the gross interest income that would have been recorded in accordance with the original terms of non-accruing credit card loans was $7 million for the three months ended March 31, 2015 and 2014. The Company does not separately track the amount of gross interest income that would have been recorded in accordance with the original terms of loans. This amount was estimated based on customers' current balances and most recent interest rates.
[3] Personal loans that are 90 or more days delinquent and accruing interest include $3 million of loans accounted for as troubled debt restructurings at March 31, 2015 and December 31, 2014.
[4] Private student loans that are 90 or more days delinquent and accruing interest include $5 million of loans accounted for as troubled debt restructurings at March 31, 2015 and December 31, 2014.