Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Servicing fees	$ 1,333	$ 1,351	$ 4,135	$ 3,986
Management fees	474	419	1,411	1,198
Trading services	288	259	907	823
Securities finance	128	147	423	459
Processing fees and other	57	66	140	209
Total fee revenue	2,280	2,242	7,016	6,675
Net interest income	672	603	1,974	1,688
Gains (losses) related to investment securities, net	(1)	1	6	(39)
Total revenue	2,951	2,846	8,996	8,324
Provision for loan losses	5	3	7	4
Total expenses	2,079	2,021	6,494	6,138
Income before income tax expense (benefit)	$ 867	$ 822	$ 2,495	$ 2,182
Pre-tax margin	29.00%	29.00%	28.00%	26.00%
Investment Servicing
Segment Reporting Information [Line Items]
Total revenue	$ 2,444		$ 7,496
Investment Management
Segment Reporting Information [Line Items]
Total revenue	507		1,500
Operating Segments \| Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees	1,333	$ 1,351	4,135	$ 3,986
Management fees	0	0	0	0
Trading services	255	239	810	768
Securities finance	128	147	423	459
Processing fees and other	49	65	131	203
Total fee revenue	1,765	1,802	5,499	5,416
Net interest income	680	606	1,991	1,691
Gains (losses) related to investment securities, net	(1)	1	6	(39)
Total revenue	2,444	2,409	7,496	7,068
Provision for loan losses	5	3	7	4
Total expenses	1,693	1,673	5,244	5,050
Income before income tax expense (benefit)	$ 746	$ 733	$ 2,245	$ 2,014
Pre-tax margin	31.00%	30.00%	30.00%	28.00%
Operating Segments \| Investment Management
Segment Reporting Information [Line Items]
Servicing fees	$ 0	$ 0	$ 0	$ 0
Management fees	474	419	1,411	1,198
Trading services	33	20	97	55
Securities finance	0	0	0	0
Processing fees and other	8	1	9	6
Total fee revenue	515	440	1,517	1,259
Net interest income	(8)	(3)	(17)	(3)
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	507	437	1,500	1,256
Provision for loan losses	0	0	0	0
Total expenses	386	314	1,173	954
Income before income tax expense (benefit)	$ 121	$ 123	$ 327	$ 302
Pre-tax margin	24.00%	28.00%	22.00%	24.00%
Other
Segment Reporting Information [Line Items]
Servicing fees	$ 0	$ 0	$ 0	$ 0
Management fees	0	0	0	0
Trading services	0	0	0	0
Securities finance	0	0	0	0
Processing fees and other	0	0	0	0
Total fee revenue	0	0	0	0
Net interest income	0	0	0	0
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	0	0	0	0
Provision for loan losses	0	0	0	0
Total expenses	0	34	77	134
Income before income tax expense (benefit)	$ 0	$ (34)	$ (77)	$ (134)

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Trading Services Revenue

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Income from services rendered by trust departments or by any consolidated subsidiaries acting in a fiduciary capacity, including fees earned for (1) acting as an agent for fiduciary placement and loans and (2) custody or investment advisory services when such fees are not separately billed to the customer. This item excludes commissions and fees received for the accumulation or disbursement of funds deposited to Individual Retirement or Keogh plan accounts when such are not handled by the reporting entity's trust department.

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Amount of fee and commission revenue classified as other.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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The net amount of operating interest income (expense).

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Amount of revenue from providing investment advisory, asset management and administrative services, including, but not limited to, distribution and shareholder services, accounting, tax, legal, regulatory filing, share registration, and shareholder correspondence activities.

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Amount of fees and commissions from banking, advisory, brokerage, and securities underwriting activities. Activities include, but are not limited to, underwriting securities, private placements of securities, investment advisory and management services, merger and acquisition services, sale and servicing of mutual funds, and other related consulting fees.

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This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

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Total aggregate amount of all noninterest 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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Amount of expense related to estimated loss from loan and lease transactions.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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