Fair Value Measurements - Quantitative Information about Recurring Fair Value Measurement of Assets and Liabilities Classified as Level 3 (Detail) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)		Jun. 30, 2017 USD ($)		Dec. 31, 2016 USD ($)
Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		$ 2,160	$ 2,207	$ 2,113	$ 2,178		$ 2,172		$ 3,356
Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		86,653	88,988
Liabilities, Fair Value Disclosure		(53,201)	(68,270)
Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		2,288	2,359
Liabilities, Fair Value Disclosure		(1,603)	(1,690)
Deposits [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Liabilities, Fair Value Disclosure	[1],[2]	(943)	(897)
Borrowings [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Liabilities, Fair Value Disclosure	[1],[2]	(532)	(641)
Credit contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[3]	64	114	110	115		143		193
Credit contracts [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		64	114
Equity contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[3]	10	81	2	56		32		(2)
Equity contracts [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[2]	10	81
Foreign exchange contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[3]	(1)	0	(1)	0		0		0
Foreign exchange contracts [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[2]	(1)	0
Interest rate contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[3]				0		0		1
Interest rate contracts [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure			0
Other Contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[3],[4]	(45)	(46)	(51)	(46)		(44)		(9)
Other Contracts [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		(45)	(46)
Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[5]	112	129	131	125		131		184
Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		112	129
Trading assets, excluding derivatives [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		112	129
Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		16	0	0
Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		16	16
Trading assets, excluding derivatives [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		16	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		16
Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		92	0	0
Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		92	91
Trading assets, excluding derivatives [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		92	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		92
Trading assets, excluding derivatives [Member] | Corporate and other domestic debt securities [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[5]	1,803	1,803	1,803	1,803		1,803		2,884
Trading assets, excluding derivatives [Member] | Corporate and other domestic debt securities [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		1,803	1,803
Trading assets, excluding derivatives [Member] | Corporate and other domestic debt securities [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		1,803	1,803
Available-for-sale securities [Member] | Other asset-backed securities available-for-sale [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[6]	105	111	107	110	[7]	107	[7]	105
Available-for-sale securities [Member] | Other asset-backed securities available-for-sale [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[8]	105	510
Available-for-sale securities [Member] | Other asset-backed securities available-for-sale [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[8]	105	111
Other assets [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	[9]	4	15	$ 12	$ 15		$ 0		$ 0
Other assets [Member] | Recurring [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[10]	4	15
Other assets [Member] | Recurring [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	[10]	$ 4	$ 15
Measurement Input, Prepayment Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.00	0.00
Measurement Input, Prepayment Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.01	0.06
Measurement Input, Prepayment Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.00
Measurement Input, Prepayment Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.05
Measurement Input, Prepayment Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.07
Measurement Input, Prepayment Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.10
Measurement Input, Default Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.00	0.04
Measurement Input, Default Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.01	0.06
Measurement Input, Default Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.01
Measurement Input, Default Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.04
Measurement Input, Default Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.01
Measurement Input, Default Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.02
Measurement Input, Default Rates [Member] | Credit contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input			0.82
Measurement Input, Default Rates [Member] | Credit contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input			0.83
Measurement Input, Loss Severity Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.90	0.55
Measurement Input, Loss Severity Rates [Member] | Collateralized debt obligations [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.95	0.60
Measurement Input, Loss Severity Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.80
Measurement Input, Loss Severity Rates [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.85
Measurement Input, Loss Severity Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.25
Measurement Input, Loss Severity Rates [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.40
Measurement Input, Discount Margin [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.0100
Measurement Input, Discount Margin [Member] | Residential mortgage asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.0250
Measurement Input, Discount Margin [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.0087
Measurement Input, Discount Margin [Member] | Student loan asset-backed securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Broker Quotes or Consensus Pricing [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.0120
Measurement Input, Spread Volatility on Collateral Assets [Member] | Corporate and other domestic debt securities [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.01	0.02
Measurement Input, Spread Volatility on Collateral Assets [Member] | Corporate and other domestic debt securities [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.04	0.04
Measurement Input, Correlation between Insurance Claim Shortfall and Collateral Value [Member] | Corporate and other domestic debt securities [Member] | Recurring [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Trading, Measurement Input		0.80	0.80
Measurement Input, Probability to Fund for Rate Lock Commitments [Member] | Interest rate contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Market Comparable Adjusted for Probability to Fund [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input			0.41
Measurement Input, Probability to Fund for Rate Lock Commitments [Member] | Interest rate contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Market Comparable Adjusted for Probability to Fund [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input			1.00
Measurement Input, Implied Volatility of Currency Pairs [Member] | Deposits [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input	[1],[2]	0.08	0.06
Measurement Input, Implied Volatility of Currency Pairs [Member] | Deposits [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input	[1],[2]	0.10	0.09
Measurement Input, Implied Volatility of Currency Pairs [Member] | Borrowings [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.08	0.06
Measurement Input, Implied Volatility of Currency Pairs [Member] | Borrowings [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.10	0.09
Measurement Input, Implied Volatility of Currency Pairs [Member] | Foreign exchange contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.08	0.06
Measurement Input, Implied Volatility of Currency Pairs [Member] | Foreign exchange contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.10	0.09
Measurement Input, Equity / Equity Index Volatility [Member] | Deposits [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input	[1],[2]	0.07	0.07
Measurement Input, Equity / Equity Index Volatility [Member] | Deposits [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input	[1],[2]	0.35	0.42
Measurement Input, Equity / Equity Index Volatility [Member] | Borrowings [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.07	0.07
Measurement Input, Equity / Equity Index Volatility [Member] | Borrowings [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.37	0.42
Measurement Input, Equity / Equity Index Volatility [Member] | Equity contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.07	0.07
Measurement Input, Equity / Equity Index Volatility [Member] | Equity contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.37	0.42
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Deposits [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input		0.43	0.42
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Deposits [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Domestic Deposits, Measurement Input		0.51	0.80
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Borrowings [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.44	0.42
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Borrowings [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Adjusted Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	[1],[2]	0.79	0.80
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Equity contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.43	0.42
Measurement Input, Equity/Equity and Equity/Index Correlation [Member] | Equity contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.79	0.80
Measurement Input, Equity Dividend Yields [Member] | Equity contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.00	0.00
Measurement Input, Equity Dividend Yields [Member] | Equity contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	[2]	0.07	0.08
Measurement Input, Credit Default Swap Spreads [Member] | Credit contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input		0.0067	0.0154
Measurement Input, Credit Default Swap Spreads [Member] | Credit contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Option Pricing Model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input		0.0087	0.0174
Measurement Input, Conversion Rate [Member] | Other Contracts [Member] | Recurring [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input		1.6	1.6
Measurement Input, Expected Duration [Member] | Other Contracts [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Contract, Duration, Measurement Input		2 years	2 years
Measurement Input, Expected Duration [Member] | Other Contracts [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative Contract, Duration, Measurement Input		4 years	4 years
Measurement Input, Market Assumptions Related to Yields for Comparable Instruments [Member] | Other asset-backed securities available-for-sale [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input		0.01	0.01
Measurement Input, Market Assumptions Related to Yields for Comparable Instruments [Member] | Other asset-backed securities available-for-sale [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input		0.03	0.03
Measurement Input, Client Transfer Rates Based on Rating [Member] | Recurring [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Other Assets, Measurement Input		0.50	0.50
Measurement Input, Client Transfer Rates Based on Rating [Member] | Recurring [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Other Assets, Measurement Input		0.95	0.95

[1] Structured deposits and structured notes contain embedded derivative features whose fair value measurements contain significant Level 3 inputs.

[2] We are the client-facing entity and we enter into identical but opposite derivatives to transfer the resultant risks to our affiliates. With the exception of counterparty credit risks, we are market neutral. The corresponding intra-group derivatives are presented as equity derivatives and foreign exchange derivatives in the table.

[3] Level 3 net derivatives included derivative assets of $156 million and derivative liabilities of $128 million at September 30, 2018 and derivative assets of $294 million and derivative liabilities of $169 million at September 30, 2017. Gains (losses) on derivatives, net are predominantly included in trading revenue in the consolidated statement of income.

[4] Consists of swap agreements entered into in conjunction with the sales of Visa Class B Shares.

[5] Gains (losses) on trading assets, excluding derivatives are included in trading revenue in the consolidated statement of income.

[6] Realized gains (losses) on securities available-for-sale are included in other securities gains (losses), net in the consolidated statement of income. Unrealized gains (losses) on securities available-for-sale are included in other comprehensive income (loss).

[7] .

[8] Securities available-for-sale are recorded at fair value through other comprehensive income (loss).

[9] Represents contingent consideration receivable associated with the sale of a portion of our Private Banking business. Gains (losses) associated with this transaction are included in other income (loss) in the consolidated statement of income.

[10] Represents contingent consideration receivable associated with the sale of a portion of our Private Banking business.