Derivative Positions (Detail) - USD ($) $ in Millions		Dec. 31, 2017		Dec. 31, 2016
Derivative Asset, Notional Amount		$ 143,238		$ 127,456
Derivative Asset, Fair Value, Gross Asset		3,904		4,514
Derivative Liability, Notional Amount		106,467		146,506
Derivative Liability, Fair Value, Gross Liability		4,442		4,902
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement		3,904		4,514
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement		4,442		4,902
Derivative, Fair Value, Amount Offset Against Collateral, Net		(2,731)		(3,239)
Derivative Liability, Fair Value, Gross Asset		2,731		3,239
Derivative Asset, Collateral, Obligation to Return Cash, Offset		(371)		(291)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		(1,303)		(1,265)
Derivative Assets	[1]	(802)		(984)
Derivative Liabilities	[2]	408		398
Mortgage Servicing Rights [Member] | Interest rate futures [Member]
Derivative Liability, Notional Amount		16,600		6,700
Loans Held For Sale [Member] | Interest rate futures [Member]
Derivative Asset, Notional Amount		190		720
Other Trading [Member] | Interest rate futures [Member]
Derivative Asset, Notional Amount		9,800		12,300
Not Designated as Hedging Instrument [Member]
Derivative Asset, Notional Amount		136,108	[3]	120,396	[4]
Derivative Asset, Fair Value, Gross Asset		3,901	[3]	4,478	[4]
Derivative Liability, Notional Amount		93,417	[3]	130,916	[4]
Derivative Liability, Fair Value, Gross Liability		4,132	[3]	4,556	[4]
Not Designated as Hedging Instrument [Member] | Mortgage Servicing Rights [Member]
Derivative Asset, Notional Amount		31,895	[3],[5]	12,165	[4],[6]
Derivative Asset, Fair Value, Gross Asset		119	[3],[5]	413	[4],[6]
Derivative Liability, Notional Amount		10,126	[3],[5]	18,774	[4],[6]
Derivative Liability, Fair Value, Gross Liability		119	[3],[5]	335	[4],[6]
Not Designated as Hedging Instrument [Member] | Loans Held For Sale [Member]
Derivative Asset, Notional Amount		4,550	[3],[7]	11,774	[4],[8]
Derivative Asset, Fair Value, Gross Asset		9	[3],[7]	134	[4],[8]
Derivative Liability, Notional Amount		3,040	[3],[7]	8,306	[4],[8]
Derivative Liability, Fair Value, Gross Liability		6	[3],[7]	58	[4],[8]
Not Designated as Hedging Instrument [Member] | Loans Held For Investment [Member]
Derivative Asset, Notional Amount		90	[3]	100	[4]
Derivative Asset, Fair Value, Gross Asset		2	[3]	2	[4]
Derivative Liability, Notional Amount		85	[3]	36	[4]
Derivative Liability, Fair Value, Gross Liability		2	[3]	1	[4]
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Asset, Notional Amount		3,409	[3]	3,231	[4]
Derivative Asset, Fair Value, Gross Asset		110	[3]	161	[4]
Derivative Liability, Notional Amount		3,649	[3]	3,360	[4]
Derivative Liability, Fair Value, Gross Liability		102	[3]	148	[4]
Not Designated as Hedging Instrument [Member] | Equity Contract [Member]
Derivative Asset, Notional Amount		13,837	[3],[9]	17,225	[4],[10]
Derivative Asset, Fair Value, Gross Asset		2,499	[3],[9]	2,095	[4],[10]
Derivative Liability, Notional Amount		25,070	[3],[9]	28,658	[4],[10]
Derivative Liability, Fair Value, Gross Liability		2,857	[3],[9]	2,477	[4],[10]
Not Designated as Hedging Instrument [Member] | Other Contract [Member]
Derivative Asset, Notional Amount		1,671	[3],[11]	2,412	[4],[12]
Derivative Asset, Fair Value, Gross Asset		18	[3],[11]	28	[4],[12]
Derivative Liability, Notional Amount		346	[3],[11]	668	[4],[12]
Derivative Liability, Fair Value, Gross Liability		16	[3],[11]	22	[4],[12]
Not Designated as Hedging Instrument [Member] | Commodity [Member]
Derivative Asset, Notional Amount		712	[3]	747	[4]
Derivative Asset, Fair Value, Gross Asset		63	[3]	75	[4]
Derivative Liability, Notional Amount		710	[3]	746	[4]
Derivative Liability, Fair Value, Gross Liability		61	[3]	73	[4]
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Trading [Member]
Derivative Asset, Notional Amount		78,223	[3],[9]	70,599	[4],[10]
Derivative Asset, Fair Value, Gross Asset		1,066	[3],[9]	1,536	[4],[10]
Derivative Liability, Notional Amount		48,143	[3],[9]	67,477	[4],[10]
Derivative Liability, Fair Value, Gross Liability		946	[3],[9]	1,401	[4],[10]
Not Designated as Hedging Instrument [Member] | Credit Risk Contract [Member] | Loans Held For Investment [Member]
Derivative Asset, Notional Amount		0	[3]	15	[4]
Derivative Asset, Fair Value, Gross Asset		0	[3]	0	[4]
Derivative Liability, Notional Amount		515	[3]	620	[4]
Derivative Liability, Fair Value, Gross Liability		11	[3]	8	[4]
Not Designated as Hedging Instrument [Member] | Credit Risk Contract [Member] | Other Trading [Member]
Derivative Asset, Notional Amount		1,721	[3],[13]	2,128	[4],[14]
Derivative Asset, Fair Value, Gross Asset		15	[3],[13]	34	[4],[14]
Derivative Liability, Notional Amount		1,733	[3],[13]	2,271	[4],[14]
Derivative Liability, Fair Value, Gross Liability		12	[3],[13]	33	[4],[14]
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative Asset, Notional Amount		5,850	[15]	6,400	[16]
Derivative Asset, Fair Value, Gross Asset		2	[15]	34	[16]
Derivative Liability, Notional Amount		8,350	[15]	11,050	[16]
Derivative Liability, Fair Value, Gross Liability		252	[15]	265	[16]
Fair Value Hedging [Member] | Interest Rate Contract [Member]
Derivative Asset, Notional Amount		1,280	[17]	660	[18]
Derivative Asset, Fair Value, Gross Asset		1	[17]	2	[18]
Derivative Liability, Notional Amount		4,700	[17]	4,540	[18]
Derivative Liability, Fair Value, Gross Liability		58	[17]	81	[18]
Fair Value Hedging [Member] | Fixed Income Interest Rate [Member]
Derivative Asset, Notional Amount		1,250	[17]	600	[18]
Derivative Asset, Fair Value, Gross Asset		1	[17]	2	[18]
Derivative Liability, Notional Amount		4,670	[17]	4,510	[18]
Derivative Liability, Fair Value, Gross Liability		58	[17]	81	[18]
Fair Value Hedging [Member] | Brokered Time Deposits [Member]
Derivative Asset, Notional Amount		30	[17]	60	[18]
Derivative Asset, Fair Value, Gross Asset		0	[17]	0	[18]
Derivative Liability, Notional Amount		30	[17]	30	[18]
Derivative Liability, Fair Value, Gross Liability		$ 0	[17]	$ 0	[18]

[1] At December 31, 2017, $802 million, net of $371 million offsetting cash collateral, is recognized in Trading assets and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2016, $984 million, net of $291 million offsetting cash collateral, is recognized in Trading assets and derivative instruments within the Company's Consolidated Balance Sheets.

[2] At December 31, 2017, $408 million, net of $1.3 billion offsetting cash collateral, is recognized in Trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2016, $398 million, net of $1.3 billion offsetting cash collateral, is recognized in Trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets.

[3] See “Economic Hedging and Trading Activities” in this Note for further discussion.

[4] See “Economic Hedging and Trading Activities” in this Note for further discussion.

[5] Amount includes $16.6 billion of notional amounts related to interest rate futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table.

[6] Amount includes $6.7 billion of notional amounts related to interest rate futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table.

[7] Amount includes $190 million of notional amounts related to interest rate futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table.

[8] Amount includes $720 million of notional amounts related to interest rate futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table.

[9] Amounts include $9.8 billion of notional amounts related to interest rate futures and $1.2 billion of notional amounts related to equity futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table. Amounts also include notional amounts related to interest rate swaps hedging fixed rate debt.

[10] Amounts include $12.3 billion of notional amounts related to interest rate futures and $629 million of notional amounts related to equity futures. These futures contracts settle in cash daily, one day in arrears. The derivative asset or liability associated with the one day lag is included in the fair value column of this table. Amounts also include notional amounts related to interest rate swaps hedging fixed rate debt.

[11] Includes $49 million notional amount that is based on the 3.2 million of Visa Class B shares, the conversion ratio from Class B shares to Class A shares, and the Class A share price at the derivative inception date of May 28, 2009. This derivative was established upon the sale of Class B shares in the second quarter of 2009. See Note 16, “Guarantees” for additional information.

[12] Includes $49 million notional amount that is based on the 3.2 million of Visa Class B shares, the conversion ratio from Class B shares to Class A shares, and the Class A share price at the derivative inception date of May 28, 2009. This derivative was established upon the sale of Class B shares in the second quarter of 2009. See Note 16, “Guarantees” for additional information.

[13] Asset and liability amounts include $4 million and $11 million, respectively, of notional amounts from purchased and written credit risk participation agreements, whose notional is calculated as the notional of the derivative participated adjusted by the relevant RWA conversion factor.

[14] Asset and liability amounts include $5 million and $13 million, respectively, of notional amounts from purchased and written credit risk participation agreements, whose notional is calculated as the notional of the derivative participated adjusted by the relevant RWA conversion factor.

[15] See “Cash Flow Hedges” in this Note for further discussion.

[16] See “Cash Flow Hedges” in this Note for further discussion.

[17] See “Fair Value Hedges” in this Note for further discussion.

[18] See “Fair Value Hedges” in this Note for further discussion.