Changes in Accumulated Other Comprehensive (Loss) Income (Details 1) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other non-interest revenue	$ 349	$ 379	$ 726	$ 740
Interest expense on long-term debt and other	411	345	762	639
Other expenses	(1,313)	(1,346)	(2,747)	(2,716)
Reclassification out of accumulated other comprehensive income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Increase (decrease) due to amounts reclassified into earnings	0	0	0	0
Reclassification out of accumulated other comprehensive income [Member] | Net Unrealized Gains (Losses) on Investment Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other non-interest revenue	0		0
Income tax provision for other non-interest revenue	0	0	0
Other non-interest revenue, net of taxes	0		0
Reclassification out of accumulated other comprehensive income [Member] | Foreign Currency Translation Adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other expenses	0	0	1	0
Income tax benefit for other, net expense	0	0	(1)	0
Other, net expense, net of taxes	0	0	0	0
Increase (decrease) due to amounts reclassified into earnings	$ 0	$ 0	$ 0	$ 0