Parent Company (Details 1) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 32,359	$ 23,932	$ 27,445
Other assets	17,679	14,217
Total assets	191,367	198,321	189,000
Liabilities and Shareholders’ Equity
Long-term debt	42,952	57,835
Total liabilities	168,383	175,250
Shareholders' Equity
Preferred shares	0	0
Common shares	161	163
Additional paid-in capital	11,881	11,774
Retained earnings	13,837	13,871
Accumulated other comprehensive loss	(2,895)	(2,737)
Total shareholders’ equity	22,984	23,071	$ 22,290	$ 18,261
Total liabilities and shareholders’ equity	191,367	198,321
Parent Company Details (Textuals) [Abstract]
Premises and equipment, accumulated depreciation	7,540	6,562
Parent Company [Member]
Assets
Cash and cash equivalents	10,968	4,430
Equity in net assets of subsidiaries and affiliates	23,306	23,165
Loans to subsidiaries and affiliates	15,887	22,350
Due from subsidiaries and affiliates	1,084	1,168
Other assets	164	223
Total assets	51,409	51,336
Liabilities and Shareholders’ Equity
Accounts payable and other liabilities	1,743	2,197
Due to subsidiaries and affiliates	1,100	609
Short-term debt of subsidiaries and affiliates	2,772	1,091
Long-term debt	22,810	24,368
Total liabilities	28,425	28,265
Shareholders' Equity
Total shareholders’ equity	22,984	23,071
Total liabilities and shareholders’ equity	$ 51,409	$ 51,336