Parent Company (Details 2) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net income	$ 1,693	$ 1,755	$ 1,761	$ 1,550	$ 2,010	$ 1,654	$ 1,623	$ 1,634	$ 6,759	$ 6,921	$ 2,748
Adjustments to reconcile net income to net cash provided by operating activities:
Net cash provided by operating activities									13,632	8,930	13,540
Cash Flows from Investing Activities
Purchase of investments									(11,166)	(5,434)	(2,612)
Maturities and redemptions of investment securities									7,329	3,499	2,494
Other investing activities									152	0	0
Net cash used in investing activities									(16,707)	(19,615)	(18,242)
Cash Flows from Financing Activities
Proceeds from long-term borrowings									12,706	21,524	32,764
Payments of long-term debt									(13,850)	(18,895)	(24,082)
Issuance of American Express common shares and other									86	87	129
Dividends paid									(1,422)	(1,324)	(1,251)
Net cash (used in) provided by financing activities									(519)	5,101	12,245
Net (decrease) increase in cash, cash equivalents and restricted cash									(3,362)	(5,455)	7,769
Cash. cash equivalents and restricted cash at beginning of year				27,808				33,263	27,808	33,263	25,494
Cash, cash equivalents and restricted cash at end of year	24,446				27,808				24,446	27,808	33,263
Parent Company [Member]
Cash Flows from Operating Activities
Net income									6,759	6,921	2,748
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net income of subsidiaries and affiliates									(7,271)	(7,452)	(3,186)
Dividends received from subsidiaries and affiliates									6,370	3,222	5,755
Other operating activities, primarily with subsidiaries and affiliates									1,315	(257)	659
Net cash provided by operating activities									7,173	2,434	5,976
Cash Flows from Investing Activities
Maturities and redemptions of investment securities									1	0	0
Loans to subsidiaries and affiliates									(4,405)	(6,281)	(4,044)
Investments in subsidiaries and affiliates									(15)	(30)	0
Other investing activities									82	0	0
Net cash used in investing activities									(4,337)	(6,311)	(4,044)
Cash Flows from Financing Activities
Proceeds from long-term borrowings									6,469	9,350	5,900
Payments of long-term debt									(641)	(3,850)	(1,500)
Short-term debt of subsidiaries and affiliates									(1,500)	(140)	(1,313)
Issuance of American Express common shares and other									86	87	129
Repurchase of American Express common shares									(4,685)	(1,685)	(4,400)
Dividends paid									(1,422)	(1,324)	(1,251)
Net cash (used in) provided by financing activities									(1,693)	2,438	(2,435)
Net (decrease) increase in cash, cash equivalents and restricted cash									1,143	(1,439)	(503)
Cash. cash equivalents and restricted cash at beginning of year				$ 3,287				$ 4,726	3,287	4,726	5,229
Cash, cash equivalents and restricted cash at end of year	$ 4,430				$ 3,287				$ 4,430	$ 3,287	$ 4,726