Other Assets (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Other Assets [Line Items]
Foreign deferred tax liabilities	$ 174	$ 98
Tax Credit Investments - Affordable Housing partnerships	1,006	1,018
Reclassification of Net assets previously reported within Other intangible assets				$ 796
Gross Carrying Amount	702	2,105
Finite-Lived Intangible Assets, Accumulated Amortization	427	1,206
Other Assets (Textuals) [Abstract]
Accumulated goodwill impairment losses	221	220
Amortization expense	212	207	$ 194
Community Reinvestment Act Tax Credit Investments	$ 1,043	1,023
Minimum [Member]
Other Assets [Line Items]
Finite-Lived Intangible Assets, Useful Life	1 year
Maximum [Member]
Other Assets [Line Items]
Finite-Lived Intangible Assets, Useful Life	22 years
Other Expense [Member]
Other Assets [Line Items]
Loss from Affordable Housing Projects Equity Method Investments	$ 126	112
Income Tax Provision [Member]
Other Assets [Line Items]
QAH Tax Credits for equity method losses	97	74
Other Liabilities [Member]
Other Assets [Line Items]
QAH Investment Commitment	237
Variable Interest Enterprise [Member]
Other Assets [Line Items]
Affordable Housing Program Off Balance Sheet Obligation	59
Tax Credit Investments - Affordable Housing partnerships	936	$ 933
Variable Interest Enterprise [Member] | Other Liabilities [Member]
Other Assets [Line Items]
QAH Investment Commitment	$ 228
Earliest Year [Member] | Other Liabilities [Member]
Other Assets [Line Items]
Affordable Housing Tax Credits Commitment Year To Be Paid	2019
Latest Year [Member] | Other Liabilities [Member]
Other Assets [Line Items]
Affordable Housing Tax Credits Commitment Year To Be Paid	2033