Fair Value Disclosures - Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Total realized and unrealized gains (losses): Included in earnings:
Mortgage banking income	$ 154	$ 111	$ 356	$ 351
Non-agency MBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	559	688	626	745
Total realized and unrealized gains (losses): Included in earnings:
Interest income	6	5	38	21
Mortgage banking income	0
Other noninterest income	0
Included in unrealized net holding gains (losses) in OCI	(5)	(11)	(50)	(36)
Purchases	0
Issuances	0
Sales	0
Settlements	(21)	(25)	(75)	(73)
Ending balance	539	657	539	657
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	6	5	38	21
MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	785	912	880	844
Total realized and unrealized gains (losses): Included in earnings:
Interest income	0
Mortgage banking income	42	(90)	(154)	(21)
Other noninterest income	0
Included in unrealized net holding gains (losses) in OCI	0
Purchases	0
Issuances	44	57	100	125
Sales	0
Settlements	(43)	(31)	(121)	(100)
Other			123
Ending balance	828	848	828	848
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	42	(90)	(154)	(21)
Net Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	33	(2)	4	17
Total realized and unrealized gains (losses): Included in earnings:
Interest income	0
Mortgage banking income	45	20	101	68
Other noninterest income	0	(1)		(3)
Included in unrealized net holding gains (losses) in OCI	0
Purchases	0
Issuances	22	26	85	67
Sales	0
Settlements	(80)	(26)	(170)	(132)
Ending balance	20	17	20	17
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	20	19	20	19
Private Equity and Similar Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	353	359	289	329
Total realized and unrealized gains (losses): Included in earnings:
Interest income	0
Mortgage banking income	0
Other noninterest income	3	25	6	44
Included in unrealized net holding gains (losses) in OCI	0
Purchases	15	7	89	62
Issuances	0
Sales	(29)	(90)	(37)	(119)
Settlements	(2)		(7)	(15)
Other			0
Ending balance	340	301	340	301
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	$ 1	$ (7)	$ 1	$ 8