Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Non-interest revenues
Discount revenue	$ 6,181		$ 5,700		$ 18,264		$ 16,830
Net card fees	870		786		2,544		2,305
Other fees and commissions	798		755		2,365		2,212
Other	334		372		1,060		1,112
Total non-interest revenues	8,183		7,613		24,233		22,459
Interest income
Interest on loans	2,554		2,131		7,267		5,943
Interest and dividends on investment securities	35		22		83		68
Deposits with banks and other	149		92		390		233
Total interest income	2,738		2,245		7,740		6,244
Interest expense
Deposits	340		213		910		538
Long-term debt and other	437		355		1,199		994
Total interest expense	777		568		2,109		1,532
Net interest income	1,961		1,677		5,631		4,712
Total revenues net of interest expense	10,144		9,290		29,864		27,171
Provisions for losses
Charge card	214		214		701		590
Card Member loans	560		531		1,587		1,272
Other	43		25		110		64
Total provisions for losses	817		770		2,398		1,926
Total revenues net of interest expense after provisions for losses	9,327		8,520		27,466		25,245
Expenses
Marketing and business development	1,642		1,446		4,650		4,187
Card Member rewards	2,400		2,168		7,180		6,425
Card Member services	457		351		1,282		1,009
Salaries and employee benefits	1,350		1,265		3,956		3,822
Other, net	1,360		1,459		4,107		4,175
Total expenses	7,209		6,689		21,175		19,618
Pretax income	2,118		1,831		6,291		5,627
Income tax provision	464		472		1,380		1,673
Net income	$ 1,654		$ 1,359		$ 4,911		$ 3,954
Earnings Per Common Share, Basic (Note 15) [Abstract]
Net income attributable to common shareholders	$ 1.89	[1]	$ 1.51	[1]	$ 5.6	[2]	$ 4.34	[2]
Earnings Per Common Share, Diluted (Note 15) [Abstract]
Net income attributable to common shareholders	$ 1.88	[1]	$ 1.51	[1]	$ 5.59	[2]	$ 4.33	[2]
Average common shares outstanding for earnings per common share:
Basic	858		878		859		889
Diluted	860		881		861		892
Cash dividends declared per common share	$ 0.39		$ 0.35		$ 1.09		$ 0.99

[1] Rep resents net income less (i) earnings allocated to participating share awards of $ 13 million and $ 11 million for the three months ended September 30 , 2018 and 2017 , respectively, and (ii) dividends on preferred shares of $ 20 million and $ 21 million for the three months ended September 30 , 2018 and 2017 , respectively .

[2] Represents net income less (i) earnings allocated to participating share awards of $ 38 million and $ 32 million for the nine months ended September 30 , 2018 and 2017 , respectively, and (ii) dividends on preferred shares of $ 61 million for both the nine months ended September 30 , 2018 and 2017 .