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The net amount of operating interest income (expense).

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The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

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Revenue from Contracts with Customers - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Servicing fees	$ 1,251	$ 1,421
Management fees	420	472
Foreign exchange trading services	280	304
Securities finance	118	141
Processing fees and other	191	77
Total fee revenue	2,260	2,415
Net interest income	673	643	$ 673	$ 643
Gains (losses) related to investment securities, net	(1)	(2)
Total revenue	2,932	3,056
Servicing fees
Disaggregation of Revenue [Line Items]
Servicing fees	1,251	1,421
Management fees
Disaggregation of Revenue [Line Items]
Management fees	420	472
Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Foreign exchange trading services	280	304
Securities finance
Disaggregation of Revenue [Line Items]
Securities finance	118	141
Processing fees and other
Disaggregation of Revenue [Line Items]
Processing fees and other	191	77
Total fee revenue
Disaggregation of Revenue [Line Items]
Total fee revenue	2,260	2,415
Net interest income
Disaggregation of Revenue [Line Items]
Net interest income	673	643
Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Gains (losses) related to investment securities, net	(1)	(2)
Operating Segments \| Investment Servicing
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,523	1,612
All other revenue	949	947
Servicing fees	1,251	1,421
Management fees	0	0
Foreign exchange trading services	246	274
Securities finance	117	141
Processing fees and other	180	77
Total fee revenue	1,794	1,913
Net interest income	679	648
Gains (losses) related to investment securities, net	(1)	(2)
Total revenue	2,472	2,559
Operating Segments \| Investment Servicing \| Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,251	1,421
All other revenue	0	0
Servicing fees	1,251	1,421
Operating Segments \| Investment Servicing \| Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	0	0
Management fees	0	0
Operating Segments \| Investment Servicing \| Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	86	95
All other revenue	160	179
Foreign exchange trading services	246	274
Operating Segments \| Investment Servicing \| Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	70	77
All other revenue	47	64
Securities finance	117	141
Operating Segments \| Investment Servicing \| Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	116	19
All other revenue	64	58
Processing fees and other	180	77
Operating Segments \| Investment Servicing \| Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,523	1,612
All other revenue	271	301
Total fee revenue	1,794	1,913
Operating Segments \| Investment Servicing \| Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	679	648
Net interest income	679	648
Operating Segments \| Investment Servicing \| Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	(1)	(2)
Gains (losses) related to investment securities, net	(1)	(2)
Operating Segments \| Investment Management
Disaggregation of Revenue [Line Items]
Topic 606 revenue	454	502
All other revenue	6	(5)
Servicing fees	0	0
Management fees	420	472
Foreign exchange trading services	34	30
Securities finance	1	0
Processing fees and other	11	0
Total fee revenue	466	502
Net interest income	(6)	(5)
Gains (losses) related to investment securities, net	0	0
Total revenue	460	497
Operating Segments \| Investment Management \| Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	0	0
Servicing fees	0	0
Operating Segments \| Investment Management \| Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	420	472
All other revenue	0	0
Management fees	420	472
Operating Segments \| Investment Management \| Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	34	30
All other revenue	0	0
Foreign exchange trading services	34	30
Operating Segments \| Investment Management \| Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	1	0
Securities finance	1	0
Operating Segments \| Investment Management \| Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	11	0
Processing fees and other	11	0
Operating Segments \| Investment Management \| Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	454	502
All other revenue	12	0
Total fee revenue	466	502
Operating Segments \| Investment Management \| Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	(6)	(5)
Net interest income	(6)	(5)
Operating Segments \| Investment Management \| Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	0	0
Gains (losses) related to investment securities, net	0	0
Other
Disaggregation of Revenue [Line Items]
Servicing fees	0	0
Management fees	0	0
Foreign exchange trading services	0	0
Securities finance	0	0
Processing fees and other	0	0
Total fee revenue	0	0
Net interest income	0	0
Gains (losses) related to investment securities, net	0	0
Total revenue	$ 0	0
Effect of Change
Disaggregation of Revenue [Line Items]
Net interest income		15
Effect of Change \| Processing fees and other
Disaggregation of Revenue [Line Items]
Processing fees and other		(15)
Effect of Change \| Net interest income
Disaggregation of Revenue [Line Items]
Net interest income		$ 15