Goodwill and Other Intangible Assets - Mortgage Servicing Rights (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Mortgage servicing rights activity [Abstract]
Fair value at the beginning of the period	$ 6,608	$ 7,436
MSR activity:
Originations of MSRs	107	155
Purchase of MSRs	0	1
Disposition of MSRs	(64)	(157)
Net additions	43	(1)
Changes due to collection/realization of expected cash flows	(241)	(215)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	(762)	(477)
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	7	(10)
Discount rates	7	(10)
Prepayment model changes and other	(4)	(82)
Total changes in valuation due to other inputs and assumptions	10	(102)
Total changes in valuation due to inputs and assumptions	(752)	(579)
Fair value at March 31	5,658	6,641
Change in unrealized gains/(losses) included in income related to MSRs	(752)	(579)
Contractual service fees, late fees and other ancillary fees included in income	561	667
Third-party mortgage loans serviced	658,000	728,000
Net servicer advances	$ 6,100	$ 7,900