Undesignated derivatives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Customer-facing interest rate derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain recognized on undesignated derivatives	$ 146	$ 7
Total [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain recognized on undesignated derivatives	40	35
Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain recognized on undesignated derivatives	22	18
Other interest rate. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain recognized on undesignated derivatives	1	1
Offsetting interest rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain recognized on undesignated derivatives	$ 129	$ 11