Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents
Securities purchased under resale agreements	$ 230	$ 87
Accounts receivable
Card Member receivables, gross	44,728	57,413
Card Member receivables, reserves	459	619
Loans
Card Member loans, gross	77,700	87,381
Card Member loans, reserves	5,236	2,383
Other loans, reserves	241	152
Accumulated depreciation and amortization	6,799	6,562
Restricted cash of consolidated variable interests	2,513	514
Liabilities [Abstract]
Long-term debt of consolidated variable interest entities	$ 52,588	$ 57,835
Shareholders' Equity
Preferred shares, par value (in dollars per share)	$ 1.667	$ 1.667
Preferred shares, authorized	20,000,000	20,000,000
Preferred shares, issued	1,600	1,600
Preferred shares, outstanding	1,600	1,600
Common shares, par value (in dollars per share)	$ 0.20	$ 0.20
Common shares, authorized	3,600,000,000	3,600,000,000
Common shares, issued	805,000,000	810,000,000
Common shares, outstanding	805,000,000	810,000,000
Accumulated other comprehensive loss
Net unrealized securities gains, tax	$ 29	$ 11
Foreign currency translation adjustments, tax	(59)	(319)
Net unrealized pension and other postretirement benefits, tax	(196)	(208)
Variable Interest Entity, Primary Beneficiary [Member]
Accounts receivable
Card Member receivables, gross	3,815	8,284
Loans
Card Member loans, gross	28,103	32,230
Restricted cash of consolidated variable interests	2,013	85
Liabilities [Abstract]
Long-term debt of consolidated variable interest entities	$ 16,275	$ 19,668