Securities Financing Arrangements (Details 2) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 33,377	$ 36,255
Securities loaned	333	661
Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities loaned	233	570
Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities loaned	0	0
31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities loaned	100	91
Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities loaned	0	0
U.S. Treasury securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	11,539	13,970
U.S. Treasury securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	8,410	11,419
U.S. Treasury securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	2,671	1,523
U.S. Treasury securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	433	712
U.S. Treasury securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	25	316
U.S. agency securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	40	72
U.S. agency securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	40	42
U.S. agency securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	30
U.S. agency securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
U.S. agency securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Other sovereign government obligations
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	17	16
Other sovereign government obligations | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Other sovereign government obligations | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Other sovereign government obligations | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	17	16
Other sovereign government obligations | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Money market securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	32
Money market securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	29
Money market securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0
Money market securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	3
Money market securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0
Asset-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	99	101
Asset-backed securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	5	20
Asset-backed securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	3	15
Asset-backed securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	91	66
Asset-backed securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	18,936	17,992
Mortgage-backed securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	7,815	8,792
Mortgage-backed securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	4,966	4,450
Mortgage-backed securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	6,005	4,750
Mortgage-backed securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	150	0
Corporate bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	1,681	2,114
Securities loaned	14	8
Corporate bonds | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	455	405
Securities loaned	14	8
Corporate bonds | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	181	800
Securities loaned	0	0
Corporate bonds | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	1,045	909
Securities loaned	0	0
Corporate bonds | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Securities loaned	0	0
Municipal securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	373	438
Municipal securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	173	74
Municipal securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	37	65
Municipal securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	163	299
Municipal securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Equities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	327	891
Securities loaned	319	653
Equities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	148	452
Securities loaned	219	562
Equities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	27	275
Securities loaned	0	0
Equities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	152	164
Securities loaned	100	91
Equities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	0	0
Securities loaned	0	0
Trading Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	33,044	35,594
Trading Securities | Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	17,075	21,204
Trading Securities | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	7,885	7,158
Trading Securities | 31-90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	7,909	6,916
Trading Securities | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 175	$ 316