Derivatives - Other Risk Management Derivatives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest rate lock commitments
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging	$ 165	$ 73	$ 47
Other income \| Interest rate risk on mortgage activities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging	446	315	(107)
Other income \| Credit risk on loans
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging	(68)	(58)	9
Other income \| Interest rate and foreign currency risk on ALM activities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging	(2,971)	1,112	3,278
Other income \| Price risk on deferred compensation hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging	$ 700	$ 943	$ (495)