Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Non-interest revenues
Discount revenue	$ 4,425	$ 4,218	$ 13,164	$ 12,398
Net card fees	633	622	1,858	1,836
Travel commissions and fees	465	480	1,437	1,457
Other commissions and fees	581	604	1,739	1,717
Other revenues	577	534	1,808	1,546
Total non-interest revenues	6,681	6,458	20,006	18,954
Interest income
Interest on loans	1,658	1,587	4,851	4,685
Interest and dividends on investment securities	60	68	193	255
Deposits with banks and other	21	33	73	71
Total interest income	1,739	1,688	5,117	5,011
Interest expense
Deposits	118	127	362	395
Long-term debt and other	440	448	1,320	1,350
Total interest expense	558	575	1,682	1,745
Net interest income	1,181	1,113	3,435	3,266
Total revenues net of interest expense	7,862	7,571	23,441	22,220
Provisions for losses
Charge card	190	174	531	533
Cardmember loans	264	48	753	104
Other	25	27	68	66
Total provisions for losses	479	249	1,352	703
Total revenues net of interest expense after provisions for losses	7,383	7,322	22,089	21,517
Expenses
Marketing, promotion, rewards and cardmember services	2,461	2,511	7,195	7,542
Salaries and employee benefits	1,516	1,598	4,687	4,715
Other, net	1,536	1,502	4,685	4,052
Total	5,513	5,611	16,567	16,309
Pretax income from continuing operations	1,870	1,711	5,522	5,208
Income tax provision	620	476	1,677	1,501
Income from continuing operations	1,250	1,235	3,845	3,707
Income from discontinued operations, net of tax	0	0	0	36
Net income	$ 1,250	$ 1,235	$ 3,845	$ 3,743
Earnings Per Share, Basic [Abstract]
Income from continuing operations attributable to common shareholders	$ 1.10	$ 1.04	$ 3.33	$ 3.09
Income from discontinued operations	$ 0	$ 0	$ 0	$ 0.03
Net income attributable to common shareholders	$ 1.10	$ 1.04	$ 3.33	$ 3.12
Earnings Per Share, Diluted [Abstract]
Income from continuing operations attributable to common shareholders	$ 1.09	$ 1.03	$ 3.31	$ 3.08
Income from discontinued operations	$ 0	$ 0	$ 0	$ 0.03
Net income attributable to common shareholders	$ 1.09	$ 1.03	$ 3.31	$ 3.11
Average common shares outstanding for earnings per common share:
Basic	1,126	1,175	1,143	1,184
Diluted	1,132	1,181	1,149	1,191
Common Stock Dividends Per Share Declared [Abstract]
Cash dividends declared per common share	$ 0.20	$ 0.18	$ 0.60	$ 0.54