Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance		$ 3,328		$ 3,504
Fair Value Assets, Purchases		14		30
Fair Value Assets, Issuances		0		0
Fair Value Assets, Settlements		(65)		(148)
Fair Value Assets, Transfers Into Level 3		106		(2)
Fair Value Assets, Transfers Out of Level 3		(92)		1
Fair Value Assets, Ending Balance		3,356		3,328
Fair Value Assets, Current Period Unrealized Gains (Losses)		41		(129)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance		(2,613)		(2,615)
Fair Value Liability, Purchases		0		0
Fair Value Liability, Issuances		(501)		(875)
Fair Value Liability, Settlements		926		593
Fair Value Liability, Transfers Into Level 3		(55)		(165)
Fair Value Liability, Transfers Out of Level 3		453		397
Fair Value Liability, Ending Balance		(1,906)		(2,613)
Fair Value Liability, Current Period Unrealized Gains (Losses)		(73)		70
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1]	1		0
Fair Value Assets, Purchases	[1]	0		0
Fair Value Assets, Issuances	[1]	0		0
Fair Value Assets, Settlements	[1]	0		0
Fair Value Assets, Transfers Into Level 3	[1]	0		0
Fair Value Assets, Transfers Out of Level 3	[1]	0		0
Fair Value Assets, Ending Balance	[1]	1		1
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1]	0		1
Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1]	0		0
Fair Value Assets, Purchases	[1]	0		0
Fair Value Assets, Issuances	[1]	0		0
Fair Value Assets, Settlements	[1]	0		0
Fair Value Assets, Transfers Into Level 3	[1]	0		0
Fair Value Assets, Transfers Out of Level 3	[1]	0		0
Fair Value Assets, Ending Balance	[1]	0		0
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1]	0		0
Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1]	(83)		42
Fair Value Assets, Purchases	[1]	0		0
Fair Value Assets, Issuances	[1]	0		0
Fair Value Assets, Settlements	[1]	13		(69)
Fair Value Assets, Transfers Into Level 3	[1]	1		(2)
Fair Value Assets, Transfers Out of Level 3	[1]	4		1
Fair Value Assets, Ending Balance	[1]	(2)		(83)
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1]	37		(82)
Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1]	179		210
Fair Value Assets, Purchases	[1]	0		0
Fair Value Assets, Issuances	[1]	0		0
Fair Value Assets, Settlements	[1]	(2)		(12)
Fair Value Assets, Transfers Into Level 3	[1]	0		0
Fair Value Assets, Transfers Out of Level 3	[1]	0		0
Fair Value Assets, Ending Balance	[1]	193		179
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1]	4		(53)
Other Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1],[2]	0
Fair Value Assets, Purchases	[1],[2]	0
Fair Value Assets, Issuances	[1],[2]	0
Fair Value Assets, Settlements	[1],[2]	(9)
Fair Value Assets, Transfers Into Level 3	[1],[2]	0
Fair Value Assets, Transfers Out of Level 3	[1],[2]	0
Fair Value Assets, Ending Balance		(9)		0	[1],[2]
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1],[2]	0
Other asset-backed securities available-for-sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[1]	0
Fair Value Assets, Purchases	[1]	0
Fair Value Assets, Issuances	[1]	0
Fair Value Assets, Settlements	[1]	0
Fair Value Assets, Transfers Into Level 3	[1]	105
Fair Value Assets, Transfers Out of Level 3	[1]	0
Fair Value Assets, Ending Balance	[1]	105		0
Fair Value Assets, Current Period Unrealized Gains (Losses)	[1]	0
Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance		221		253
Fair Value Assets, Purchases		0		0
Fair Value Assets, Issuances		0		0
Fair Value Assets, Settlements		(50)		(47)
Fair Value Assets, Transfers Into Level 3		0		0
Fair Value Assets, Transfers Out of Level 3		0		0
Fair Value Assets, Ending Balance		184		221
Fair Value Assets, Current Period Unrealized Gains (Losses)		0		4
Corporate and other domestic debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance		2,870		2,840
Fair Value Assets, Purchases		14		30
Fair Value Assets, Issuances		0		0
Fair Value Assets, Settlements		0		0
Fair Value Assets, Transfers Into Level 3		0		0
Fair Value Assets, Transfers Out of Level 3		0		0
Fair Value Assets, Ending Balance		2,884		2,870
Fair Value Assets, Current Period Unrealized Gains (Losses)		0		0
Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[3]	140		159
Fair Value Assets, Purchases	[3]	0		0
Fair Value Assets, Issuances	[3]	0		0
Fair Value Assets, Settlements	[3]	(17)		(20)
Fair Value Assets, Transfers Into Level 3	[3]	0		0
Fair Value Assets, Transfers Out of Level 3		(96)	[1]	0	[3]
Fair Value Assets, Ending Balance		0		140	[3]
Fair Value Assets, Current Period Unrealized Gains (Losses)	[3]	0		1
Domestic Deposits [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	[4]	(1,867)		(1,968)
Fair Value Liability, Purchases		0		0	[4]
Fair Value Liability, Issuances		(238)		(353)	[4]
Fair Value Liability, Settlements		623		360	[4]
Fair Value Liability, Transfers Into Level 3	[4]	(55)		(162)
Fair Value Liability, Transfers Out of Level 3		212		266	[4]
Fair Value Liability, Ending Balance		(1,407)		(1,867)	[4]
Fair Value Liability, Current Period Unrealized Gains (Losses)		(44)		10	[4]
Long-term debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance	[4]	(746)		(647)
Fair Value Liability, Purchases		0		0	[4]
Fair Value Liability, Issuances		(263)		(522)	[4]
Fair Value Liability, Settlements		303		233	[4]
Fair Value Liability, Transfers Into Level 3		0		(3)	[4]
Fair Value Liability, Transfers Out of Level 3		241		131	[4]
Fair Value Liability, Ending Balance		(499)		(746)	[4]
Fair Value Liability, Current Period Unrealized Gains (Losses)		(29)		60	[4]
Trading Gain (Loss) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	92		(59)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	0		0
Trading Gain (Loss) [Member] | Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		0
Trading Gain (Loss) [Member] | Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		0
Trading Gain (Loss) [Member] | Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	63		(55)
Trading Gain (Loss) [Member] | Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	16		(19)
Trading Gain (Loss) [Member] | Other Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[2],[5]	0
Trading Gain (Loss) [Member] | Other asset-backed securities available-for-sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0
Trading Gain (Loss) [Member] | Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	13		15
Trading Gain (Loss) [Member] | Corporate and other domestic debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	0		0
Trading Gain (Loss) [Member] | Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[3],[5]	0		0
Trading Gain (Loss) [Member] | Domestic Deposits [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	0	[6]	0	[4]
Trading Gain (Loss) [Member] | Long-term debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	0	[6]	0	[4]
Other Income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	(27)		2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	(116)		52
Other Income [Member] | Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		1
Other Income [Member] | Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		0
Other Income [Member] | Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		0
Other Income [Member] | Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0		0
Other Income [Member] | Other Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[2],[5]	0
Other Income [Member] | Other asset-backed securities available-for-sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[1],[5]	0
Other Income [Member] | Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	0		0
Other Income [Member] | Corporate and other domestic debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[5]	0		0
Other Income [Member] | Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Gains (Losses) Included In Revenue	[3],[5]	(27)		1
Other Income [Member] | Domestic Deposits [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	(82)	[6]	(10)	[4]
Other Income [Member] | Long-term debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Gains (Losses) Included In Revenue	[5]	(34)	[6]	$ 62	[4]
Level 3 [Member] | Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Ending Balance	[3]	$ 0

[1] Level 3 net derivatives included derivative assets of $391 million and derivative liabilities of $208 million at December 31, 2016 and derivative assets of $346 million and derivative liabilities of $249 million at December 31, 2015.

[2] Consists of swap agreements entered into in conjunction with the sale of certain Visa Class B Shares.

[3] See Note 9, "Intangible Assets," for additional information.

[4] See Note 15, "Fair Value Option," for additional information.

[5] Includes realized and unrealized gains and losses.

[6] See Note 9, "Intangible Assets," for additional information.