Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Card Member receivables, gross	$ 55,893,000	$ 54,047,000
Card Member loans	81,854,000	73,399,000
Other assets	10,471,000	9,746,000
Short-term borrowings	3,100,000	3,278,000
Long-term debt	58,423,000	55,804,000
Cash and cash equivalents
Securities purchased under resale agreements	64,000	48,000
Accounts receivable
Card Member receivables, reserves	573,000	521,000	$ 467,000
Other receivables, reserves	25,000	31,000
Loans
Balance, January 1	2,134,000	1,706,000	1,223,000
Other loans, reserves	124,000	80,000
Premises and equipment, accumulated depreciation	6,015,000	5,455,000
Restricted cash included in Other assets per Consolidated Balance Sheets	363,000	336,000	286,000
Accumulated other comprehensive income (loss)
Net unrealized securities losses, Tax	(107,000)	215,000	$ (139,000)
Foreign currency translation adjustments, tax	(300,000)	(363,000)
Net unrealized pension and other postretirement benefit losses, net of tax	(170,000)	(179,000)
Net Unrealized Securities Losses, Tax	$ 1,000	$ (1,000)
Common shares, par value	$ 0.2	$ 0.2
Common shares, authorized	3,600,000,000	3,600,000,000	3,600,000,000
Common shares, issued	847,000,000	859,000,000	904,000,000
Common shares, outstanding	847,000,000	859,000,000
Preferred shares, authorized	20,000,000	20,000,000
Preferred shares, issued	1,600	1,600	0
Preferred shares, outstanding	1,600	1,600	0
Preferred shares, par value	$ 1.67	$ 1.67
Variable Interest Enterprise [Member]
Card Member receivables, gross	$ 8,539,000	$ 8,919,000
Card Member loans	33,194,000	25,695,000
Long-term debt	19,509,000	18,560,000
Loans
Restricted cash included in Other assets per Consolidated Balance Sheets	$ 70,000	$ 62,000