Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and cash equivalents	$ 4,348	$ 4,082	$ 4,348	$ 4,082	$ 5,753	$ 4,807
Other assets	8,119		8,119		8,496
Liabilities
Commercial paper and other short-term borrowings	6,195		6,195		2,360
Other Liabilities	2,551		2,551		2,520
Interest and Dividend Income, Operating [Abstract]
Securities borrowed or purchased under resale agreements	83	44	146	94
Interest Expense
Commercial paper and other short-term borrowings	10	7	18	10
Long-term debt	60	63	117	136
Securities loaned or sold under repurchase agreements	84	31	143	63
Noninterest Income
Fees from affiliates	211	258	430	470
Noninterest Expense
Other Noninterest Expense	112	117	232	246
Transferred Entities | Affiliated Entity
Assets [Abstract]
Cash and cash equivalents	58		58		102
Securities borrowed or purchased under resale agreements	2,790		2,790		2,765
Other assets	83		83		161
Liabilities
Related Party Deposit Liabilities	460		460		623
Securities loaned or sold under repurchase agreements	150		150		385
Commercial paper and other short-term borrowings	1,667		1,667		1,372
Long-term debt	5,945		5,945		6,042
Other Liabilities	83		83		$ 63
Interest and Dividend Income, Operating [Abstract]
Loans	0	(2)	0	(2)
Securities borrowed or purchased under resale agreements	9	6	15	12
Interest Expense
Commercial paper and other short-term borrowings	2	5	3	11
Long-term debt	32	7	60	13
Securities loaned or sold under repurchase agreements	2	0	3	1
Noninterest Income
Fees from affiliates	211	258	430	470
Other, net	(7)	13	(5)	13
Noninterest Expense
Other Noninterest Expense	$ 20	$ 24	$ 46	$ 79