Employee Benefits and Other Expenses Employee Benefits and Other Expenses, Expenses Not Otherwise Shown Separately In Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Expenses Not Otherwise Shown Separately In Financial Statement [Abstract]
Outside professional services	$ 727	$ 678
Contract services	630	563
Operating losses	464	238
Leases	260	286
Advertising and promotion	181	237
Other	955	1,141
Total other noninterest expense	$ 3,217	$ 3,143