Fair Value (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

	Fair-Value Measurements on a Recurring Basis
	as of March 31, 2017
(In millions)	Quoted Market Prices in Active Markets (Level 1)		Pricing Methods with Significant Observable Market Inputs (Level 2)		Pricing Methods with Significant Unobservable Market Inputs (Level 3)		Impact of Netting(1)			Total Net Carrying Value in Consolidated Statement of Condition
Assets:
Trading account assets:
U.S. government securities	$	39	$	—	$	—				$	39
Non-U.S. government securities	366		187		—					553
Other	—		353		—					353
Total trading account assets	405		540		—					945
AFS Investment securities:
U.S. Treasury and federal agencies:
Direct obligations	2,731		420		—					3,151
Mortgage-backed securities	—		11,348		—					11,348
Asset-backed securities:
Student loans	—		5,592		99					5,691
Credit cards	—		1,302		—					1,302
Sub-prime	—		252		—					252
Other(2)	—		100		771					871
Total asset-backed securities	—		7,246		870					8,116
Non-U.S. debt securities:
Mortgage-backed securities	—		6,583		—					6,583
Asset-backed securities	—		2,752		59					2,811
Government securities	—		5,804		—					5,804
Other(3)	—		5,546		256					5,802
Total non-U.S. debt securities	—		20,685		315					21,000
State and political subdivisions	—		9,783		39					9,822
Collateralized mortgage obligations	—		2,422		39					2,461
Other U.S. debt securities	—		2,426		—					2,426
U.S. equity securities	—		44		—					44
Non-U.S. equity securities	—		2		—					2
U.S. money-market mutual funds	—		424		—					424
Non-U.S. money-market mutual funds	—		16		—					16
Total investment securities available-for-sale	2,731		54,816		1,263					58,810
Other assets:
Derivative instruments:
Foreign exchange contracts	—		9,159		2		$	(6,151	)	3,010
Interest-rate contracts	9		—		—		(3		)	6
Total derivative instruments	9		9,159		2		(6,154		)	3,016
Total assets carried at fair value	$	3,145	$	64,515	$	1,265	$	(6,154	)	$	62,771
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	—	$	8,891	$	1	$	(5,334	)	$	3,558
Interest-rate contracts	—		113		—		(4		)	109
Other derivative contracts	—		389		—		—			389
Total derivative instruments	—		9,393		1		(5,338		)	4,056
Total liabilities carried at fair value	$	—	$	9,393	$	1	$	(5,338	)	$	4,056

⁽¹⁾ Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $1,211 million and $393 million, respectively, for cash collateral received from and provided to derivative counterparties.

⁽²⁾ As of March 31, 2017, the fair value of other asset-backed securities was primarily composed of $871 million of collateralized loan obligations.

⁽³⁾ As of March 31, 2017, the fair value of other non-U.S. debt securities was primarily composed of $3,742 million of covered bonds and $1,054 million of corporate bonds.

	Fair-Value Measurements on a Recurring Basis
	as of December 31, 2016
(In millions)	Quoted Market Prices in Active Markets (Level 1)		Pricing Methods with Significant Observable Market Inputs (Level 2)		Pricing Methods with Significant Unobservable Market Inputs (Level 3)		Impact of Netting(1)			Total Net Carrying Value in Consolidated Statement of Condition
Assets:
Trading account assets:
U.S. government securities	$	30	$	—	$	—				$	30
Non-U.S. government securities	495		174		—					669
Other	—		325		—					325
Total trading account assets	525		499		—					1,024
AFS Investment securities:
U.S. Treasury and federal agencies:
Direct obligations	3,824		439		—					4,263
Mortgage-backed securities	—		13,257		—					13,257
Asset-backed securities:
Student loans	—		5,499		97					5,596
Credit cards	—		1,351		—					1,351
Sub-prime	—		272		—					272
Other(2)	—		—		905					905
Total asset-backed securities	—		7,122		1,002					8,124
Non-U.S. debt securities:
Mortgage-backed securities	—		6,535		—					6,535
Asset-backed securities	—		2,484		32					2,516
Government securities	—		5,836		—					5,836
Other(3)	—		5,365		248					5,613
Total non-U.S. debt securities	—		20,220		280					20,500
State and political subdivisions	—		10,283		39					10,322
Collateralized mortgage obligations	—		2,577		16					2,593
Other U.S. debt securities	—		2,469		—					2,469
U.S. equity securities	—		42		—					42
Non-U.S. equity securities	—		3		—					3
U.S. money-market mutual funds	—		409		—					409
Non-U.S. money-market mutual funds	—		16		—					16
Total investment securities available-for-sale	3,824		56,837		1,337					61,998
Other assets:
Derivatives instruments:
Foreign exchange contracts	—		16,476		8		$	(9,163	)	7,321
Interest-rate contracts	—		68		—		(68		)	—
Total derivative instruments	—		16,544		8		(9,231		)	7,321
Total assets carried at fair value	$	4,349	$	73,880	$	1,345	$	(9,231	)	$	70,343
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	—	$	15,948	$	8	$	(10,456	)	$	5,500
Interest-rate contracts	—		348		—		(226		)	122
Other derivative contracts	—		380		—		—			380
Total derivative instruments	—		16,676		8		(10,682		)	6,002
Total liabilities carried at fair value	$	—	$	16,676	$	8	$	(10,682	)	$	6,002

⁽¹⁾ Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $906 million and $2,356 million, respectively, for cash collateral received from and provided to derivative counterparties.

⁽²⁾ As of December 31, 2016, the fair value of other asset-backed securities was primarily composed of $905 million of collateralized loan obligations.

⁽³⁾ As of December 31, 2016, the fair value of other non-U.S. debt securities was primarily composed of $3,769 million of covered bonds and $988 million of corporate bonds.

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The following tables present activity related to our level 3 financial assets during the three months ended March 31, 2017 and 2016, respectively. Transfers into and out of level 3 are reported as of the beginning of the period presented. During the three months ended March 31, 2017 there were no transfers out of level 3. During the three months ended March 31, 2016, transfers out of level 3 were mainly related to certain mortgage- and asset-backed securities, including non-U.S. debt securities, for which fair value was measured using prices for which observable market information became available.

	Fair Value Measurements Using Significant Unobservable Inputs
	Three Months Ended March 31, 2017
	Fair Value  as of December 31, 2016		Total Realized and Unrealized Gains (Losses)					Purchases		Settlements			Fair Value as of March 31, 2017(2)		Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of March 31, 2017
(In millions)			Recorded in Revenue(1)			Recorded in Other Comprehensive Income(1)
Assets:
AFS Investment securities:
Asset-backed securities:
Student loans	$	97	$	—		$	2	$	—	$	—		$	99
Other	905		1			—		155		(290		)	771
Total asset-backed securities	1,002		1			2		155		(290		)	870
Non-U.S. debt securities:
Asset-backed securities	32		—			—		31		(4		)	59
Other	248		—			—		5		3			256
Total Non-U.S. debt securities	280		—			—		36		(1		)	315
State and political subdivisions	39		—			—		—		—			39
Collateralized mortgage obligations	16		—			—		23		—			39
Total AFS investment securities	1,337		1			2		214		(291		)	1,263
Other assets:
Derivative instruments:
Foreign exchange contracts	8		(7		)	—		5		(4		)	2		$	(3	)
Total derivative instruments	8		(7		)	—		5		(4		)	2		(3		)
Total assets carried at fair value	$	1,345	$	(6	)	$	2	$	219	$	(295	)	$	1,265	$	(3	)

⁽¹⁾ Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services.

⁽²⁾ There were no transfers of assets into level 3 during the three months ended March 31, 2017.

	Fair-Value Measurements Using Significant Unobservable Inputs
	Three Months Ended March 31, 2016
	Fair Value  as of December 31, 2015		Total Realized and Unrealized Gains (Losses)					Purchases		Settlements			Transfers out of Level 3			Fair Value  as of March 31, 2016(2)		Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of March 31, 2016
(In millions)			Recorded in Revenue(1)		Recorded in Other Comprehensive Income(1)
Assets:
AFS Investment securities:
U.S. Treasury and federal agencies, mortgage-backed securities	$	—	$	—	$	—		$	300	$	—		$	—		$	300
Asset-backed securities:
Student loans	189		—		(3		)	—		—			—			186
Other	1,764		7		(11		)	113		(60		)	—			1,813
Total asset-backed securities	1,953		7		(14		)	113		(60		)	—			1,999
Non-U.S. debt securities:
Asset-backed securities	174		—		—			53		(18		)	(82		)	127
Other	255		—		(2		)	29		13			—			295
Total non-U.S. debt securities	429		—		(2		)	82		(5		)	(82		)	422
State and political subdivisions	33		—		—			—		(1		)	—			32
Collateralized mortgage obligations	39		—		—			50		(7		)	—			82
Other U.S. debt securities	10		—		—			—		(10		)	—			—
Total AFS investment securities	2,464		7		(16		)	545		(83		)	(82		)	2,835
Other assets:
Derivative instruments:
Foreign exchange contracts	5		3		—			—		(8		)	—			—		$	—
Total derivative instruments	5		3		—			—		(8		)	—			—		—
Total assets carried at fair value	$	2,469	$	10	$	(16	)	$	545	$	(91	)	$	(82	)	$	2,835	$	—

⁽¹⁾ Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services.

⁽²⁾ There were no transfers of assets into level 3 during the three months ended March 31, 2016.

Fair Value Inputs, Assets, Quantitative Information

The following table presents quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our level 3 financial assets and liabilities measured at fair value on a recurring basis for which we use internally-developed pricing models. The significant unobservable inputs for our level 3 financial assets and liabilities whose fair value is measured using pricing information from non-binding broker or dealer quotes are not included in the table, as the specific inputs applied are not provided by the broker/dealer.

	Quantitative Information about Level 3 Fair-Value Measurements
	Fair Value						Weighted-Average
(Dollars in millions)	As of March 31, 2017		As of December 31, 2016		Valuation Technique	Significant Unobservable Input(1)	As of March 31, 2017		As of December 31, 2016
Significant unobservable inputs readily available to State Street:
Assets:
Asset-backed securities, other	$	—	$	1	Discounted cash flows	Credit spread	—	%	0.3	%
State and political subdivisions	39		39		Discounted cash flows	Credit spread	1.8		1.8
Derivative instruments, foreign exchange contracts	2		8		Option model	Volatility	9.2		14.4
Total	$	41	$	48
Liabilities:
Derivative instruments, foreign exchange contracts	$	1	$	8	Option model	Volatility	9.4		14.4
Total	$	1	$	8

⁽¹⁾ Significant changes in these unobservable inputs would result in significant changes in fair value measurement.

Fair Value Inputs, Liabilities, Quantitative Information

The following table presents quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our level 3 financial assets and liabilities measured at fair value on a recurring basis for which we use internally-developed pricing models. The significant unobservable inputs for our level 3 financial assets and liabilities whose fair value is measured using pricing information from non-binding broker or dealer quotes are not included in the table, as the specific inputs applied are not provided by the broker/dealer.

	Quantitative Information about Level 3 Fair-Value Measurements
	Fair Value						Weighted-Average
(Dollars in millions)	As of March 31, 2017		As of December 31, 2016		Valuation Technique	Significant Unobservable Input(1)	As of March 31, 2017		As of December 31, 2016
Significant unobservable inputs readily available to State Street:
Assets:
Asset-backed securities, other	$	—	$	1	Discounted cash flows	Credit spread	—	%	0.3	%
State and political subdivisions	39		39		Discounted cash flows	Credit spread	1.8		1.8
Derivative instruments, foreign exchange contracts	2		8		Option model	Volatility	9.2		14.4
Total	$	41	$	48
Liabilities:
Derivative instruments, foreign exchange contracts	$	1	$	8	Option model	Volatility	9.4		14.4
Total	$	1	$	8

⁽¹⁾ Significant changes in these unobservable inputs would result in significant changes in fair value measurement.

Carrying Value and Estimated Fair Value of Financial Instruments by Fair Value Hierarchy

The following tables present the reported amounts and estimated fair values of the financial assets and liabilities not carried at fair value on a recurring basis, as they would be categorized within the fair-value hierarchy, as of the dates indicated.

					Fair-Value Hierarchy
(In millions)	Reported Amount		Estimated Fair Value		Quoted Market Prices in Active Markets (Level 1)		Pricing Methods with Significant Observable Market Inputs (Level 2)		Pricing Methods with Significant Unobservable Market Inputs (Level 3)
March 31, 2017
Financial Assets:
Cash and due from banks	$	2,909	$	2,909	$	2,909	$	—	$	—
Interest-bearing deposits with banks	66,789		66,789		—		66,789		—
Securities purchased under resale agreements	2,181		2,181		—		2,181		—
Investment securities held-to-maturity	35,829		35,694		17,395		18,164		135
Net loans (excluding leases)(1)	21,653		21,657		—		21,567		90
Financial Liabilities:
Deposits:
Non-interest-bearing	$	56,786	$	56,786	$	—	$	56,786	$	—
Interest-bearing - U.S.	26,746		26,746		—		26,746		—
Interest-bearing - non-U.S.	99,933		99,933		—		99,933		—
Securities sold under repurchase agreements	4,003		4,003		—		4,003		—
Other short-term borrowings	1,177		1,177		—		1,177		—
Long-term debt	11,394		11,624		—		11,301		323

⁽¹⁾ Includes $28 million of loans classified as held-for-sale that were measured at fair value on a non-recurring basis as of March 31, 2017.

					Fair-Value Hierarchy
(In millions)	Reported Amount		Estimated Fair Value		Quoted Market Prices in Active Markets (Level 1)		Pricing Methods with Significant Observable Market Inputs (Level 2)		Pricing Methods with Significant Unobservable Market Inputs (Level 3)
December 31, 2016
Financial Assets:
Cash and due from banks	$	1,314	$	1,314	$	1,314	$	—	$	—
Interest-bearing deposits with banks	70,935		70,935		—		70,935		—
Securities purchased under resale agreements	1,956		1,956		—		1,956		—
Investment securities held-to-maturity	35,169		34,994		17,400		17,439		155
Net loans (excluding leases)	18,862		18,877		—		18,781		96
Financial Liabilities:
Deposits:
Non-interest-bearing	$	59,397	$	59,397	$	—	$	59,397	$	—
Interest-bearing - U.S.	30,911		30,911		—		30,911		—
Interest-bearing - non-U.S.	96,855		96,855		—		96,855		—
Securities sold under repurchase agreements	4,400		4,400		—		4,400		—
Other short-term borrowings	1,585		1,585		—		1,585		—
Long-term debt	11,430		11,618		—		11,282		336