Noninterest Revenue and Noninterest Expense - Other Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Noninterest Income (Expense) [Abstract]
Operating lease income	$ 1,112	$ 873	$ 2,159	$ 1,697