Changes in Accumulated Other Comprehensive (Loss) Income (Details 1) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other non-interest revenue	$ 334	$ 372	$ 1,060	$ 1,112
Interest expense on long-term debt and other	437	355	1,199	994
Other expenses	(1,360)	(1,459)	(4,107)	(4,175)
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	1	0	1
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	(6)	1	(6)
Income tax benefit for other, net expense	0	7	(1)	7
Increase (decrease) due to amounts reclassified into earnings	$ 0	$ 1	$ 0	$ 1