Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

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The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

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Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.

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Fair value of securities received as collateral against derivative assets.

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Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Derivative Liability, Fair Value, Gross Liability	$ 2,857		$ 2,857		$ 2,716
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	186		186
Derivative, Notional Amount	255,352		255,352		233,052
Derivative Asset, Fair Value, Gross Asset	3,518		3,518		2,631
Netted counterparty balance [Member]
Fair Value, Concentration of Risk, Derivative Instruments, Assets	1,100		1,100		541
Derivative Asset, Fair Value of Collateral	342		342		350
Netted counterparty balance gains [Member]
Fair Value, Concentration of Risk, Derivative Instruments, Assets	1,500		1,500		891
Derivative liability positions containing provisions conditioned on downgrades [Member]
Derivative Liability, Fair Value, Gross Liability	1,200		1,200		$ 589
Additional Termination Event [Member]
Derivative Liability, Fair Value, Gross Liability	1		1
Additional Termination Event [Member] \| Maximum [Member]
Derivative Liability, Fair Value, Gross Liability	13		13
Credit Support Annex [Member]
Derivative Liability, Fair Value, Gross Liability	1,200		1,200
Collateral Already Posted, Aggregate Fair Value	862		862
Credit Support Annex [Member] \| Moody's, Baa3 Rating [Member]
Additional Collateral, Aggregate Fair Value	2		2
Credit Support Annex [Member] \| Moody's, Ba1 Rating [Member]
Additional Collateral, Aggregate Fair Value	11		$ 11
Financial Guarantee [Member]
Derivative, Average Remaining Maturity			6 years 1 month 6 days		5 years 10 months 24 days
Credit Derivative, Maximum Exposure, Undiscounted	273		$ 273		$ 217
Financial Guarantee [Member] \| Minimum [Member]
Derivative, Remaining Maturity			1 year		1 year
Financial Guarantee [Member] \| Maximum [Member]
Derivative, Remaining Maturity			11 years		10 years
Interest Rate Contract [Member] \| Cash Flow Hedging [Member]
Derivative, Average Remaining Maturity			2 years 9 months 18 days		2 years 6 months
Interest Rate Contract [Member] \| Minimum [Member] \| Cash Flow Hedging [Member]
Derivative, Remaining Maturity			1 year		1 year
Interest Rate Contract [Member] \| Maximum [Member] \| Cash Flow Hedging [Member]
Derivative, Remaining Maturity			7 years		5 years
Interest Income [Member] \| Loans Held-For-Investment [Member] \| Interest Rate Contract [Member] \| Cash Flow Hedging [Member]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	$ 143	$ (61)	$ 204	$ (225)