Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Non-interest revenues
Discount revenue		$ 5,889	$ 5,387
Net card fees		830	748
Other fees and commissions		781	711
Other		377	361
Total non-interest revenues		7,877	7,207
Interest income
Interest on loans		2,326	1,862
Interest and dividends on investment securities		21	23
Deposits with banks and other		115	60
Total interest income		2,462	1,945
Interest expense
Deposits		270	149
Long-term debt and other		351	294
Total interest expense		621	443
Net interest income		1,841	1,502
Total revenues net of interest expense		9,718	8,709
Provisions for losses
Charge card		242	213
Card Member loans		499	337
Other		34	23
Total provisions for losses		775	573
Total revenues net of interest expense after provisions for losses		8,943	8,136
Expenses
Marketing and business development		1,345	1,285
Card Member Rewards		2,347	2,061
Card Member services		409	317
Salaries and employee benefits		1,326	1,264
Other, net		1,434	1,370
Total expenses		6,861	6,297
Pretax income		2,082	1,839
Income tax provision		448	588
Net income		$ 1,634	$ 1,251
Earnings Per Common Share, Basic (Note 15) [Abstract]
Net income attributable to common shareholders	[1]	$ 1.86	$ 1.36
Earnings Per Common Share, Diluted (Note 15) [Abstract]
Net income attributable to common shareholders	[1]	$ 1.86	$ 1.35
Average common shares outstanding for earnings per common share:
Basic		859	899
Diluted		861	903
Cash dividends declared per common share		$ 0.35	$ 0.32

[1] Rep resents net income less (i) earnings allocated to participating share awards of $ 13 million and $ 10 million for the three months ended March 31 , 2018 and 2017 , respectively, and (ii) dividends on preferred shares of $ 21 million for both the three months ended March 31 , 2018 and 2017 .