Parent Company (Details 1) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 23,932	$ 27,445	$ 32,927
Accounts receivable, less reserves	56,794	55,320
Premises and equipment, less accumulated depreciation	4,834	4,416
Other assets	14,731	13,378
Total assets	198,321	188,602	181,000
Liabilities and Shareholders' Equity
Long-term debt	57,835	58,423
Total liabilities	175,250	166,312
Shareholders' Equity
Preferred shares	0	0
Common shares	163	170
Additional paid-in capital	11,774	12,218
Retained earnings	13,871	12,499
Accumulated other comprehensive loss	(2,737)	(2,597)
Total shareholders' equity	23,071	22,290	$ 18,261	$ 20,523
Total liabilities and shareholders' equity	198,321	188,602
Parent Company Details (Textuals) [Abstract]
Premises and equipment, accumulated depreciation	6,562	6,015
Parent Company [Member]
Assets
Cash and cash equivalents	4,430	3,287
Equity in net assets of subsidiaries and affiliates	23,165	22,298
Loans to subsidiaries and affiliates	22,350	17,945
Due from subsidiaries and affiliates	1,168	1,783
Other assets	223	297
Total assets	51,336	45,610
Liabilities and Shareholders' Equity
Accounts payable and other liabilities	2,197	1,961
Due to subsidiaries and affiliates	609	577
Short-term debt of subsidiaries and affiliates	1,091	2,591
Long-term debt	24,368	18,191
Total liabilities	28,265	23,320
Shareholders' Equity
Total shareholders' equity	23,071	22,290
Total liabilities and shareholders' equity	$ 51,336	$ 45,610