Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Detail) - USD ($) $ in Millions		Jun. 30, 2017		Dec. 31, 2016
Assets:
Available-for-sale securities, fair value	[1]	$ 31,823		$ 31,183
Trading securities		842		410
Fair value, recurring
Assets:
Available-for-sale securities, fair value		31,213	[2]	30,576	[3]
Trading securities		842		410
Residential mortgage loans held for sale		674		686
Residential mortgage loans measured at FV	[4]	142		143
Mortgage servicing rights	[5]	849
Derivative assets	[6]	780		1,057
Total assets		34,500		32,872
Liabilities:
Derivative liabilities	[7]	491		666
Short positions	[7]	22		21
Total liabilities		513		687
Interest Rate Contract | Fair value, recurring
Assets:
Derivative assets		572		748
Liabilities:
Derivative liabilities		169		265
Foreign Exchange Contract | Fair value, recurring
Assets:
Derivative assets		118		202
Liabilities:
Derivative liabilities		133		204
Equity Contract | Fair value, recurring
Liabilities:
Derivative liabilities		98		91
Commodity Contract | Fair value, recurring
Assets:
Derivative assets		90		107
Liabilities:
Derivative liabilities		91		106
U.S. Treasury and federal agencies
Assets:
Available-for-sale securities, fair value		69		549
U.S. Treasury and federal agencies | Fair value, recurring
Assets:
Available-for-sale securities, fair value		69		549
Trading securities		20		23
Obligations of states and political subdivisions
Assets:
Available-for-sale securities, fair value		45		45
Obligations of states and political subdivisions | Fair value, recurring
Assets:
Available-for-sale securities, fair value		45		45
Trading securities		27		39
Agency mortgage-backed securities | Residential mortgage backed securities
Assets:
Available-for-sale securities, fair value		16,177	[8]	15,608	[9]
Agency mortgage-backed securities | Residential mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		16,177		15,608
Trading securities		413		8
Agency mortgage-backed securities | Commercial mortgage backed securities
Assets:
Available-for-sale securities, fair value		9,262		9,055
Agency mortgage-backed securities | Commercial mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		9,262		9,055
Non-agency mortgage-backed securities | Commercial mortgage backed securities
Assets:
Available-for-sale securities, fair value		3,364		3,112
Non-agency mortgage-backed securities | Commercial mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		3,364		3,112
Asset-backed securities and other debt securities
Assets:
Available-for-sale securities, fair value		2,206		2,116
Asset-backed securities and other debt securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		2,206		2,116
Trading securities		30		15
Equity securities
Assets:
Available-for-sale securities, fair value		700	[10]	698	[11]
Equity securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		90	[2]	91	[3]
Trading securities		352		325
Fair Value, Inputs, Level 1 | Fair value, recurring
Assets:
Available-for-sale securities, fair value		158	[2],[12]	561	[3],[13]
Trading securities		352	[12]	325	[13]
Derivative assets	[6]	42	[12]	42	[13]
Total assets		552	[12]	928	[13]
Liabilities:
Derivative liabilities	[7]	10	[12]	30	[13]
Short positions	[7]	17	[12]	17	[13]
Total liabilities		27	[12]	47	[13]
Fair Value, Inputs, Level 1 | Interest Rate Contract | Fair value, recurring
Assets:
Derivative assets		3	[12]	20	[13]
Liabilities:
Derivative liabilities		3	[12]	3	[13]
Fair Value, Inputs, Level 1 | Commodity Contract | Fair value, recurring
Assets:
Derivative assets		39	[12]	22	[13]
Liabilities:
Derivative liabilities		7	[12]	27	[13]
Fair Value, Inputs, Level 1 | U.S. Treasury and federal agencies | Fair value, recurring
Assets:
Available-for-sale securities, fair value		69	[12]	471	[13]
Fair Value, Inputs, Level 1 | Equity securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		89	[2],[12]	90	[3],[13]
Trading securities		352	[12]	325	[13]
Fair Value, Inputs, Level 2 | Fair value, recurring
Assets:
Available-for-sale securities, fair value		31,055	[2],[12]	30,015	[3],[13]
Trading securities		490	[12]	85	[13]
Residential mortgage loans held for sale		674	[12]	686	[13]
Derivative assets	[6]	724	[12]	1,002	[13]
Total assets		32,943	[12]	31,788	[13]
Liabilities:
Derivative liabilities	[7]	378	[12]	540	[13]
Short positions	[7]	5	[12]	4	[13]
Total liabilities		383	[12]	544	[13]
Fair Value, Inputs, Level 2 | Interest Rate Contract | Fair value, recurring
Assets:
Derivative assets		555	[12]	715	[13]
Liabilities:
Derivative liabilities		161	[12]	257	[13]
Fair Value, Inputs, Level 2 | Foreign Exchange Contract | Fair value, recurring
Assets:
Derivative assets		118	[12]	202	[13]
Liabilities:
Derivative liabilities		133	[12]	204	[13]
Fair Value, Inputs, Level 2 | Commodity Contract | Fair value, recurring
Assets:
Derivative assets		51	[12]	85	[13]
Liabilities:
Derivative liabilities		84	[12]	79	[13]
Fair Value, Inputs, Level 2 | U.S. Treasury and federal agencies | Fair value, recurring
Assets:
Available-for-sale securities, fair value		0	[12]	78	[13]
Trading securities		20	[12]	23	[13]
Fair Value, Inputs, Level 2 | Obligations of states and political subdivisions | Fair value, recurring
Assets:
Available-for-sale securities, fair value		45	[12]	45	[13]
Trading securities		27	[12]	39	[13]
Fair Value, Inputs, Level 2 | Agency mortgage-backed securities | Residential mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		16,177	[12]	15,608	[13]
Trading securities		413	[12]	8	[13]
Fair Value, Inputs, Level 2 | Agency mortgage-backed securities | Commercial mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		9,262	[12]	9,055	[13]
Fair Value, Inputs, Level 2 | Non-agency mortgage-backed securities | Commercial mortgage backed securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		3,364	[12]	3,112	[13]
Fair Value, Inputs, Level 2 | Asset-backed securities and other debt securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		2,206	[12]	2,116	[13]
Trading securities		30	[12]	15	[13]
Fair Value, Inputs, Level 2 | Equity securities | Fair value, recurring
Assets:
Available-for-sale securities, fair value		1	[2],[12]	1	[3],[13]
Fair Value, Inputs, Level 3 | Fair value, recurring
Assets:
Residential mortgage loans measured at FV	[4]	142		143
Mortgage servicing rights	[5]	849
Derivative assets	[6]	14		13
Total assets		1,005		156
Liabilities:
Derivative liabilities	[7]	103		96
Total liabilities		103		96
Fair Value, Inputs, Level 3 | Interest Rate Contract | Fair value, recurring
Assets:
Derivative assets		14		13
Liabilities:
Derivative liabilities		5		5
Fair Value, Inputs, Level 3 | Equity Contract | Fair value, recurring
Liabilities:
Derivative liabilities		$ 98		$ 91

[1] Amortized cost of $ 31,492 and $ 31,024 at June 30, 2017 and December 31, 2016 , respectively.

[2] Excludes FHLB, FRB and DTCC restricted stock holdings totaling $ 248 , $ 360 and $ 2 , respectively, at June 30, 2017 .

[3] Excludes FHLB, FRB , and DTCC restricted stock holdings totaling $ 248 , $ 358 and $ 1 , respectively, at December 31, 2016 .

[4] Includes residential mortgage loans originated as held for sale and subsequently transferred to held for investment.

[5] Effective January 1, 2017, the Bancorp has elected the fair value measurement method for all existing classes of its residential mortgage servicing rights. The servicing rights were measured at fair value at June 30, 2017 and were measur ed under the amortization method at December 31, 2016.

[6] Included in other assets in the Condensed Consolidated Balance Sheets.

[7] Included in other liabilities in the Condensed Consolidat ed Balance Sheets.

[8] Includes interest-only mortgage-backed securities of $ 39 as of June 30, 2017 , recorded at fair value with fair value changes recorded in securities gains, net, in the Condensed Consolidated Statements of Income.

[9] Includes interest-only mortgage-backed securities of $ 60 as of December 31, 2016 , recorded at fair value with fair value changes recorded in securities gains, net, in the Condensed Consolidated Statements of Income.

[10] Equity securities consist of FHLB, FRB and DTCC restricted stock holdings of $ 248 , $ 360 and $ 2 , respectively, at June 30, 2017 , that are carried at cost, and certain mutual fund and equity security holdings.

[11] Equity securities consist of FHLB, FRB and DTCC restricted stock holdings of $ 248 , $ 358 and $ 1 , respectively, at December 31, 2016 , that are carried at cost, and certain mutual fund and equity security holdings

[12] During both the three and six months ended June 30, 2017 , no assets or liabilities were transferred between Level 1 and Level 2.

[13] During the year ended December 31, 2016 , no assets or liabilities were transferred between Level 1 and Level 2.