Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2019		Jun. 30, 2018
Non-interest revenues
Other	$ 362		$ 349		$ 725		$ 726
Total non-interest revenues	8,764		8,173		17,069		16,050
Interest income
Interest on loans	2,764		2,387		5,489		4,713
Interest and dividends on investment securities	52		27		85		48
Deposits with banks and other	149		126		345		241
Total interest income	2,965		2,540		5,919		5,002
Interest expense
Deposits	406		300		805		570
Long-term debt and other	485		411		981		762
Total interest expense	891		711		1,786		1,332
Net interest income	2,074		1,829		4,133		3,670
Total revenues net of interest expense	10,838		10,002		21,202		19,720
Provisions for losses
Charge card	224		245		477		487
Card Member loans provisions	603		528		1,128		1,027
Other	34		33		65		67
Total provisions for losses	861		806		1,670		1,581
Total revenues net of interest expense after provisions for losses	9,977		9,196		19,532		18,139
Expenses
Marketing and business development	1,773		1,663		3,346		3,008
Card Member rewards	2,652		2,433		5,103		4,780
Card Member services	563		416		1,113		825
Salaries and employee benefits	1,367		1,280		2,789		2,606
Other, net	1,403		1,313		3,004		2,747
Total expenses	7,758		7,105		15,355		13,966
Pretax income	2,219		2,091		4,177		4,173
Income tax provision	458		468		866		916
Net income	$ 1,761		$ 1,623		$ 3,311		$ 3,257
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ 2.07	[1]	$ 1.85	[1]	$ 3.88	[2]	$ 3.71	[2]
Diluted (in dollars per share)	$ 2.07	[1]	$ 1.84	[1]	$ 3.87	[2]	$ 3.70	[2]
Average common shares outstanding for earnings per common share:
Basic (in shares)	834		860		837		859
Diluted (in shares)	836		862		839		862
Discount Revenue
Non-interest revenues
Revenues and fees	$ 6,577		$ 6,194		$ 12,772		$ 12,083
Net Card Fees
Non-interest revenues
Revenues and fees	988		844		1,932		1,674
Other Fees and Commissions
Non-interest revenues
Revenues and fees	$ 837		$ 786		$ 1,640		$ 1,567

[1] Represents net income less (i) earnings allocated to participating share awards of $13 million and $12 million for the three months ended June 30, 2019 and 2018, respectively, and (ii) dividends on preferred shares of $19 million and $20 million for the three months ended June 30, 2019 and 2018, respectively.

[2] Represents net income less (i) earnings allocated to participating share awards of $24 million and $25 million for the six months ended June 30, 2019 and 2018, respectively, and (ii) dividends on preferred shares of $40 million and $41 million for the six months ended June 30, 2019 and 2018, respectively.