Other Assets (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Line Items]
Accumulated goodwill impairment losses	$ 221	$ 221
Gross carrying amount	704	702
Accumulated amortization	437	427
Amortization expense	49	212	$ 207
Tax credit investments	1,154	1,043
Tax credit investments - Affordable Housing partnerships	$ 1,109	1,006
Minimum [Member]
Other Assets [Line Items]
Estimated useful lives	1 year
Maximum [Member]
Other Assets [Line Items]
Estimated useful lives	22 years
Other Expense [Member]
Other Assets [Line Items]
Equity method losses related to QAH investments	$ 101	126
Income Tax Provision [Member]
Other Assets [Line Items]
QAH Tax Credits for equity method losses	119	97
Other Liabilities [Member]
Other Assets [Line Items]
QAH unfunded commitment	211
Variable Interest Entity, Primary Beneficiary [Member]
Other Assets [Line Items]
Tax credit investments - Affordable Housing partnerships	1,032	$ 936
Affordable Housing Program off balance sheet obligation	78
Variable Interest Entity, Primary Beneficiary [Member] | Other Liabilities [Member]
Other Assets [Line Items]
QAH unfunded commitment	$ 187
Latest Year [Member] | Other Liabilities [Member]
Other Assets [Line Items]
Affordable housing tax credits commitment, year to be paid	2043
Earliest Year [Member] | Other Liabilities [Member]
Other Assets [Line Items]
Affordable housing tax credits commitment, year to be paid	2020