Asset Quality (Credit Card and Other Consumer Loan Classes Asset Quality Indicators) (Details) - USD ($) $ in Millions	Jun. 30, 2015		Dec. 31, 2014		Jun. 30, 2014
Total Loans	$ 205,153	[1],[2]	$ 204,817	[1],[2]	$ 200,984
Credit Card [Member]
Total Loans	$ 4,520		$ 4,612
Weighted-average updated FICO score	734		732
Higher Risk Loans	$ 30		$ 35
Other Consumer [Member]
Total Loans	$ 21,844		$ 22,753
Weighted-average updated FICO score	745		744
FICO score greater than 719 | Credit Card [Member]
Total Loans	$ 2,680		$ 2,717
% of Total Loans Using FICO Credit Metric	59.00%		59.00%
FICO score greater than 719 | Other Consumer [Member]
Total Loans	$ 9,293		$ 9,156
% of Total Loans Using FICO Credit Metric	65.00%		64.00%
FICO score of 650 to 719 [Member] | Credit Card [Member]
Total Loans	$ 1,265		$ 1,288
% of Total Loans Using FICO Credit Metric	28.00%		28.00%
FICO score of 650 to 719 [Member] | Other Consumer [Member]
Total Loans	$ 3,425		$ 3,459
% of Total Loans Using FICO Credit Metric	24.00%		24.00%
FICO score of 620 to 649 [Member] | Credit Card [Member]
Total Loans	$ 193		$ 203
% of Total Loans Using FICO Credit Metric	4.00%		4.00%
FICO score of 620 to 649 [Member] | Other Consumer [Member]
Total Loans	$ 503		$ 528
% of Total Loans Using FICO Credit Metric	3.00%		4.00%
FICO score of less Than 620 [Member] | Credit Card [Member]
Total Loans	$ 208		$ 239
% of Total Loans Using FICO Credit Metric	5.00%		5.00%
FICO score of less Than 620 [Member] | Other Consumer [Member]
Total Loans	$ 578		$ 619
% of Total Loans Using FICO Credit Metric	4.00%		4.00%
No FICO score available or required [Member] | Credit Card [Member]
Total Loans	$ 174		$ 165
% of Total Loans Using FICO Credit Metric	4.00%		4.00%
No FICO score available or required [Member] | Other Consumer [Member]
Total Loans	$ 517		$ 557
% of Total Loans Using FICO Credit Metric	4.00%		4.00%
Total Loans Using FICO Credit Metric [Member] | Credit Card [Member]
Total Loans	$ 4,520		$ 4,612
% of Total Loans Using FICO Credit Metric	100.00%		100.00%
Total Loans Using FICO Credit Metric [Member] | Other Consumer [Member]
Total Loans	$ 14,316		$ 14,319
% of Total Loans Using FICO Credit Metric	100.00%		100.00%
Consumer loans using other internal credit metrics [Member] | Other Consumer [Member]
Total Loans	$ 7,528		$ 8,434
Pennsylvania [Member]
Percentage Of Higher Risk Credit Card Loans	16.00%		16.00%
Ohio [Member]
Percentage Of Higher Risk Credit Card Loans	17.00%		17.00%
Illinois [Member]
Percentage Of Higher Risk Credit Card Loans	7.00%		7.00%
Michigan [Member]
Percentage Of Higher Risk Credit Card Loans	9.00%		9.00%
Indiana [Member]
Percentage Of Higher Risk Credit Card Loans	5.00%		6.00%
Florida [Member]
Percentage Of Higher Risk Credit Card Loans	7.00%		6.00%
New Jersey [Member]
Percentage Of Higher Risk Credit Card Loans	8.00%		7.00%
North Carolina [Member]
Percentage Of Higher Risk Credit Card Loans			4.00%
All Other States [Member]
Percentage Of Higher Risk Credit Card Loans	4.00%		4.00%

[1] Amounts represent items for which we have elected the fair value option.

[2] Amounts represent the assets or liabilities of consolidated variable interest entities (VIEs).