Goodwill and Other Intangible Assets - Mortgage Servicing Rights (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mortgage servicing rights activity [Abstract]
Fair value at the beginning of the period	$ 7,436	$ 9,614	$ 7,614
MSR activity:
Originations of MSRs	550	757	2,214
Purchase of MSRs	435	11	1
Disposition of MSRs	(486)	(209)	(725)
Net additions	499	559	1,490
Changes due to collection/realization of expected cash flows	(922)	(911)	(1,102)
Changes in valuation due to inputs and assumptions:
Changes due to market interest rates and other	(160)	(1,608)	2,122
Changes in valuation due to other inputs and assumptions:
Projected cash flows (e.g., cost to service)	(112)	133	109
Discount rates	(10)	(459)	(78)
Prepayment model changes and other	(123)	108	(541)
Total changes in valuation due to other inputs and assumptions	(245)	(218)	(510)
Total changes in valuation due to inputs and assumptions	(405)	(1,826)	1,612
Fair value at December 31	6,608	7,436	9,614
Change in unrealized gains/(losses) included in income related to MSRs held	(405)	(1,826)	1,612
Contractual service fees, late fees and other ancillary fees included in income	2,533	2,884	3,309
Third-party mortgage loans serviced	677,000	756,000	822,000
Servicer advances, net of an allowance for uncollectible amounts	$ 6,500	$ 8,500	$ 9,600