Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance		$ 3,356	$ 3,328
Fair Value Assets, Gains (Losses) Included In Earnings	[1]	26	3
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1]	0	0
Fair Value Assets, Purchases		0	5
Fair Value Assets, Issuances		(17)	0
Fair Value Assets, Settlements		(14)	(13)
Fair Value Assets, Transfers Into Level 3		0	1
Fair Value Assets, Transfers Out of Level 3		0	(1)
Fair Value Assets, Ending Balance		3,351	3,323
Fair Value Assets, Current Period Unrealized Gains (Losses)		13	(13)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance		(1,906)	(2,613)
Fair Value Liability, Gains (Losses) Included In Earnings	[1]	(31)	(27)
Fair Value, Liability, Gains (Losses) Included in Other Comprehensive Income	[1]	0	0
Fair Value Liability, Purchases		0	0
Fair Value Liability, Issuances		(127)	(139)
Fair Value Liability, Settlements		206	153
Fair Value Liability, Transfers Into Level 3		(5)	(8)
Fair Value Liability, Transfers Out of Level 3		89	139
Fair Value Liability, Ending Balance		(1,774)	(2,495)
Fair Value Liability, Current Period Unrealized Gains (Losses)		(31)	(27)
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[2]	1	1
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2]	(1)	0
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2]	0	0
Fair Value Assets, Purchases	[2]	0	0
Fair Value Assets, Issuances	[2]	0	0
Fair Value Assets, Settlements	[2]	0	0
Fair Value Assets, Transfers Into Level 3	[2]	0	0
Fair Value Assets, Transfers Out of Level 3	[2]	0	0
Fair Value Assets, Ending Balance	[2]	0	1
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2]	(1)	0
Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[2]	0	0
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2]	0	0
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2]	0	0
Fair Value Assets, Purchases	[2]	0	0
Fair Value Assets, Issuances	[2]	0	0
Fair Value Assets, Settlements	[2]	0	0
Fair Value Assets, Transfers Into Level 3	[2]	0	0
Fair Value Assets, Transfers Out of Level 3	[2]	0	0
Fair Value Assets, Ending Balance	[2]	0	0
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2]	0	0
Equity contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[2]	(2)	(83)
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2]	27	24
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2]	0	0
Fair Value Assets, Purchases	[2]	0	0
Fair Value Assets, Issuances	[2]	0	0
Fair Value Assets, Settlements	[2]	(4)	4
Fair Value Assets, Transfers Into Level 3	[2]	0	1
Fair Value Assets, Transfers Out of Level 3	[2]	0	(1)
Fair Value Assets, Ending Balance	[2]	21	(55)
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2]	23	24
Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[2]	193	179
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2]	(5)	2
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2]	0	0
Fair Value Assets, Purchases	[2]	0	0
Fair Value Assets, Issuances	[2]	0	0
Fair Value Assets, Settlements	[2]	(7)	(4)
Fair Value Assets, Transfers Into Level 3	[2]	0	0
Fair Value Assets, Transfers Out of Level 3	[2]	0	0
Fair Value Assets, Ending Balance	[2]	181	177
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2]	(13)	(13)
Other Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[2],[3]	(9)
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2],[3]	0
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2],[3]	0
Fair Value Assets, Purchases	[2],[3]	0
Fair Value Assets, Issuances	[2],[3]	(17)
Fair Value Assets, Settlements	[2],[3]	0
Fair Value Assets, Transfers Into Level 3	[2],[3]	0
Fair Value Assets, Transfers Out of Level 3	[2],[3]	0
Fair Value Assets, Ending Balance		(26)
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2],[3]	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	[2]	105
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[2]	2
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[2]	0
Fair Value Assets, Purchases	[2]	0
Fair Value Assets, Issuances	[2]	0
Fair Value Assets, Settlements	[2]	0
Fair Value Assets, Transfers Into Level 3	[2]	0
Fair Value Assets, Transfers Out of Level 3	[2]	0
Fair Value Assets, Ending Balance	[2]	107
Fair Value Assets, Current Period Unrealized Gains (Losses)	[2]	2
Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance		184	221
Fair Value Assets, Gains (Losses) Included In Earnings	[1]	3	(5)
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1]	0	0
Fair Value Assets, Purchases		0	0
Fair Value Assets, Issuances		0	0
Fair Value Assets, Settlements		(3)	(6)
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	210
Fair Value Assets, Current Period Unrealized Gains (Losses)		2	(6)
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		2,884	2,870
Fair Value Assets, Gains (Losses) Included In Earnings	[1]	0	(2)
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1]	0	0
Fair Value Assets, Purchases		0	5
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	2,873
Fair Value Assets, Current Period Unrealized Gains (Losses)		0	(2)
Mortgage servicing rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Assets, Beginning Balance	[4]		140
Fair Value Assets, Gains (Losses) Included In Earnings	[1],[4]		(16)
Fair Value Assets, Gains (Losses) Included in Other Comprehensive Income	[1],[4]		0
Fair Value Assets, Purchases	[4]		0
Fair Value Assets, Issuances	[4]		0
Fair Value Assets, Settlements	[4]		(7)
Fair Value Assets, Transfers Into Level 3	[4]		0
Fair Value Assets, Transfers Out of Level 3	[4]		0
Fair Value Assets, Ending Balance	[4]		117
Fair Value Assets, Current Period Unrealized Gains (Losses)	[4]		(16)
Domestic Deposits [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance		(1,407)	(1,867)	[5]
Fair Value Liability, Gains (Losses) Included In Earnings	[1],[5]	(5)	(53)
Fair Value, Liability, Gains (Losses) Included in Other Comprehensive Income	[1],[5]	5	0
Fair Value Liability, Purchases		0	0	[5]
Fair Value Liability, Issuances		(43)	(64)	[5]
Fair Value Liability, Settlements		191	88	[5]
Fair Value Liability, Transfers Into Level 3	[5]	(3)	(8)
Fair Value Liability, Transfers Out of Level 3		46	55	[5]
Fair Value Liability, Ending Balance		(1,216)	(1,849)	[5]
Fair Value Liability, Current Period Unrealized Gains (Losses)		(4)	(50)	[5]
Long-term debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Liability, Beginning Balance		(499)	(746)	[5]
Fair Value Liability, Gains (Losses) Included In Earnings	[1],[5]	(26)	26
Fair Value, Liability, Gains (Losses) Included in Other Comprehensive Income	[1],[5]	(5)	0
Fair Value Liability, Purchases		0	0	[5]
Fair Value Liability, Issuances		(84)	(75)	[5]
Fair Value Liability, Settlements		15	65	[5]
Fair Value Liability, Transfers Into Level 3		(2)	0	[5]
Fair Value Liability, Transfers Out of Level 3		43	84	[5]
Fair Value Liability, Ending Balance		(558)	(646)	[5]
Fair Value Liability, Current Period Unrealized Gains (Losses)		$ (27)	$ 23	[5]

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

[2] Level 3 net derivatives included derivative assets of $343 million and derivative liabilities of $167 million at March 31, 2017 and derivative assets of $391 million and derivative liabilities of $268 million at March 31, 2016. Gains (losses) on derivatives, net are predominantly included in trading revenue in the consolidated statement of income.

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

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

[5] See Note 9, "Fair Value Option," for additional information. Beginning January 1, 2017, unrealized gains (losses) on fair value option liabilities attributable to credit spread is recorded in other comprehensive income.