Derivatives and Hedging Activities - Pre-Tax Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	$ 34	$ 14	$ 48	$ 26
Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	7	7	9	13
Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	8	11	20	21
Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	6	2	8	3
Credit
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(7)	(8)	(22)	(14)
Other
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	20	2	33	3
Corporate services income
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	27	20	36	40
Corporate services income | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	7	7	18	15
Corporate services income | Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	8	11	20	21
Corporate services income | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	6	2	8	3
Corporate services income | Credit
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	6	0	(10)	1
Corporate services income | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Consumer mortgage income
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	4	0	8	0
Consumer mortgage income | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Consumer mortgage income | Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Consumer mortgage income | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Consumer mortgage income | Credit
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Consumer mortgage income | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	4	0	8	0
Other income
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	3	(6)	4	(14)
Other income | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	(9)	(2)
Other income | Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Other income | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0	0	0
Other income | Credit
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(13)	(8)	(12)	(15)
Other income | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	$ 16	$ 2	$ 25	$ 3