Affordable Housing Investments.

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Other collection items presented on behalf of custody clients.

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Federal Reserve And Foreign Central Bank Deposits

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Loan receivables that will be held to maturity.

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Standby Letters of Credit

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Amount of floating rate capital debt held by the company that have an unconditional obligation requiring the issuer to redeem the securities by transferring the assets at a specified or determinable date (or dates) or upon an event that is certain to occur. The debt was issued by a business trust to outside investors where the trust uses the proceeds of the issuance of those securities to purchase, from the financial institution that established the trust, an equivalent amount of junior subordinated debentures or other loans having stated maturities. The floating rate capital debt must be redeemed upon maturity of the debentures or other loans.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Includes: (1) the amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements (Federal Funds Sold) and (2) the dollar amount outstanding of funds lent in the form of security resale agreements regardless of maturity, if the agreement requires the bank to resell the identical security purchased or a security that meets the definition of substantially the same in the case of a dollar roll. Also include purchases of participations in pools of securities, regardless of maturity (Securities Purchased Under Agreements to Re-sell).

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Amount of foreign interest-bearing deposits held by the entity.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Carrying value as of the balance sheet date of collateralized/uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Subordinated debt places a lender in a lien position behind the primary lender of the company.

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Amount of time deposit liabilities, including certificates of deposit.

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Fair Value Measurements - Fair Value Of Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and Due from Banks	$ 4,518.1	$ 5,332.0	$ 6,418.5	$ 3,021.0
Federal Reserve and Other Central Bank Deposits	40,479.1	26,674.2
Interest-Bearing Deposits with Banks	5,611.9	4,800.6
Federal Funds Sold and Resell Agreements	1,324.3	1,974.3
Securities
Available for Sale	33,742.1	35,579.8
Held to Maturity	13,049.0	8,921.1
Trading Account	0.5	0.3
Loans (excluding Leases)
Client Security Settlement Receivables	1,647.0	1,043.7
Deposits
Savings Certificates and Other Time	1,152.3	1,331.7
Non U.S. Offices Interest-Bearing	65,672.2	53,648.1
Federal Funds Purchased	2,286.1	204.8
Securities Sold Under Agreements to Repurchase	834.0	473.7
Other Borrowings	6,051.1	5,109.5
Senior Notes	1,497.3	1,496.6
Long Term Debt (excluding Leases)
Floating Rate Capital Debt	277.5	277.4
DERIVATIVE INSTRUMENTS
Assets	2,203.3	3,047.6
Liabilities	2,003.1	2,767.6
Other Financial Derivatives
DERIVATIVE INSTRUMENTS
Liabilities	30.4	25.2
Asset And Liability Management
DERIVATIVE INSTRUMENTS
Assets	60.9	494.8
Liabilities	212.0	42.2
Client Related and Trading
DERIVATIVE INSTRUMENTS
Assets	2,592.1	3,361.2
Liabilities	2,586.6	3,306.9
Client Related and Trading \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	2,527.0	3,274.2
Liabilities	2,522.5	3,221.7
Client Related and Trading \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	65.1	87.0
Liabilities	64.1	85.2
Fair Value, Inputs, Level 2
Securities
Available for Sale	28,000.0	28,100.0
Carrying (Reported) Amount, Fair Value Disclosure
ASSETS
Cash and Due from Banks	4,518.1	5,332.0
Federal Reserve and Other Central Bank Deposits	40,479.1	26,674.2
Interest-Bearing Deposits with Banks	5,611.9	4,800.6
Federal Funds Sold and Resell Agreements	1,324.3	1,974.3
Securities
Available for Sale	33,742.1	35,579.8
Held to Maturity	13,049.0	8,921.1
Trading Account	0.5	0.3
Loans (excluding Leases)
Held for Investment	32,211.1	33,354.1
Held for Sale	20.9	13.4
Client Security Settlement Receivables	1,647.0	1,043.7
Other Assets
Federal Reserve and Federal Home Loan Bank Stock	223.1	203.1
Community Development Investments	415.3	218.9
Employee Benefit and Deferred Compensation	183.4	166.2
Deposits
Demand, Noninterest-Bearing, Savings and Money Market	45,566.3	46,671.9
Savings Certificates and Other Time	1,152.3	1,331.7
Non U.S. Offices Interest-Bearing	65,672.2	53,648.1
Federal Funds Purchased	2,286.1	204.8
Securities Sold Under Agreements to Repurchase	834.0	473.7
Other Borrowings	6,051.1	5,109.5
Senior Notes	1,497.3	1,496.6
Long Term Debt (excluding Leases)
Subordinated Debt	1,435.1	1,307.9
Floating Rate Capital Debt	0.0	277.4
Floating Rate Capital Debt
Standby Letters of Credit	30.3	37.2
Loan Commitments	33.1	41.2
Carrying (Reported) Amount, Fair Value Disclosure \| Asset And Liability Management \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	30.1	335.4
Liabilities	192.6	21.2
Carrying (Reported) Amount, Fair Value Disclosure \| Asset And Liability Management \| Other Financial Derivatives
DERIVATIVE INSTRUMENTS
Liabilities	30.4	25.2
Carrying (Reported) Amount, Fair Value Disclosure \| Asset And Liability Management \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	31.9	160.2
Liabilities	19.4	22.8
Carrying (Reported) Amount, Fair Value Disclosure \| Client Related and Trading \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	2,527.0	3,274.2
Liabilities	2,522.5	3,221.7
Carrying (Reported) Amount, Fair Value Disclosure \| Client Related and Trading \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	65.1	87.0
Liabilities	64.1	85.2
Estimate of Fair Value, Fair Value Disclosure
ASSETS
Cash and Due from Banks	4,518.1	5,332.0
Federal Reserve and Other Central Bank Deposits	40,479.1	26,674.2
Interest-Bearing Deposits with Banks	5,611.9	4,800.6
Federal Funds Sold and Resell Agreements	1,324.3	1,974.3
Securities
Available for Sale	33,742.1	35,579.8
Held to Maturity	13,010.9	8,905.1
Trading Account	0.5	0.3
Loans (excluding Leases)
Held for Investment	32,375.8	33,471.3
Held for Sale	20.9	13.4
Client Security Settlement Receivables	1,647.0	1,043.7
Other Assets
Federal Reserve and Federal Home Loan Bank Stock	223.1	203.1
Community Development Investments	415.3	215.5
Employee Benefit and Deferred Compensation	181.5	162.5
Deposits
Demand, Noninterest-Bearing, Savings and Money Market	45,566.3	46,671.9
Savings Certificates and Other Time	1,153.6	1,337.5
Non U.S. Offices Interest-Bearing	65,672.2	53,648.1
Federal Funds Purchased	2,286.1	204.8
Securities Sold Under Agreements to Repurchase	834.0	473.7
Other Borrowings	6,052.9	5,113.4
Senior Notes	1,528.4	1,535.5
Long Term Debt (excluding Leases)
Subordinated Debt	1,449.8	1,316.0
Floating Rate Capital Debt	260.0	251.0
Floating Rate Capital Debt
Standby Letters of Credit	30.3	37.2
Loan Commitments	33.1	41.2
Estimate of Fair Value, Fair Value Disclosure \| Asset And Liability Management \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	30.1	335.4
Liabilities	192.6	21.2
Estimate of Fair Value, Fair Value Disclosure \| Asset And Liability Management \| Other Financial Derivatives
DERIVATIVE INSTRUMENTS
Liabilities	30.4	25.2
Estimate of Fair Value, Fair Value Disclosure \| Asset And Liability Management \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	31.9	160.2
Liabilities	19.4	22.8
Estimate of Fair Value, Fair Value Disclosure \| Client Related and Trading \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	2,527.0	3,274.2
Liabilities	2,522.5	3,221.7
Estimate of Fair Value, Fair Value Disclosure \| Client Related and Trading \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	65.1	87.0
Liabilities	64.1	85.2
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 1
ASSETS
Cash and Due from Banks	4,518.1	5,332.0
Securities
Available for Sale	5,700.3	7,522.6
Held to Maturity	35.0	15.0
Other Assets
Community Development Investments	0.0
Employee Benefit and Deferred Compensation	115.5	107.2
Deposits
Demand, Noninterest-Bearing, Savings and Money Market	45,566.3	46,671.9
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2
ASSETS
Federal Reserve and Other Central Bank Deposits	40,479.1	26,674.2
Interest-Bearing Deposits with Banks	5,611.9	4,800.6
Federal Funds Sold and Resell Agreements	1,324.3	1,974.3
Securities
Available for Sale	28,037.5	28,052.5
Held to Maturity	12,975.9	8,890.1
Trading Account	0.5	0.3
Loans (excluding Leases)
Client Security Settlement Receivables	1,647.0	1,043.7
Other Assets
Federal Reserve and Federal Home Loan Bank Stock	223.1	203.1
Community Development Investments	415.3	215.5
Employee Benefit and Deferred Compensation	66.0	55.3
Deposits
Savings Certificates and Other Time	1,153.6	1,337.5
Non U.S. Offices Interest-Bearing	65,672.2	53,648.1
Federal Funds Purchased	2,286.1	204.8
Securities Sold Under Agreements to Repurchase	834.0	473.7
Other Borrowings	6,052.9	5,113.4
Senior Notes	1,528.4	1,535.5
Long Term Debt (excluding Leases)
Subordinated Debt	1,449.8	1,316.0
Floating Rate Capital Debt	260.0	251.0
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2 \| Asset And Liability Management \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	30.1	335.4
Liabilities	192.6	21.2
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2 \| Asset And Liability Management \| Other Financial Derivatives
DERIVATIVE INSTRUMENTS
Liabilities	0.7	0.0
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2 \| Asset And Liability Management \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	31.9	160.2
Liabilities	19.4	22.8
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2 \| Client Related and Trading \| Foreign Exchange Contracts
DERIVATIVE INSTRUMENTS
Assets	2,527.0	3,274.2
Liabilities	2,522.5	3,221.7
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 2 \| Client Related and Trading \| Interest Rate Contracts
DERIVATIVE INSTRUMENTS
Assets	65.1	87.0
Liabilities	64.1	85.2
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 3
Securities
Available for Sale	4.3	4.7
Loans (excluding Leases)
Held for Investment	32,375.8	33,471.3
Held for Sale	20.9	13.4
Other Assets
Community Development Investments	0.0
Floating Rate Capital Debt
Standby Letters of Credit	30.3	37.2
Loan Commitments	33.1	41.2
Estimate of Fair Value, Fair Value Disclosure \| Fair Value, Inputs, Level 3 \| Asset And Liability Management \| Other Financial Derivatives
DERIVATIVE INSTRUMENTS
Liabilities	$ 29.7	$ 25.2