Fair Value Measurements (Fair Value Measurements - Additional Information) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2009
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net fair value of the interest rate lock commitments		$ 12
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 25 bp		6
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 50 bp		11
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 25 bp		6
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 50 bp		13
Change in fair value of interest rate lock commitments, due to 10% adverse changes in the assumed loan closing rates		1
Change in fair value of interest rate lock commitments, due to 20% adverse changes in the assumed loan closing rates		2
Change in fair value of interest rate lock commitments, due to 10% favorable changes in the assumed loan closing rates		1
Change in fair value of interest rate lock commitments, due to 20% favorable changes in the assumed loan closing rates		2
Portfolio loans to loans held for sale		238	$ 487	$ 855
Existing loans held for sale, further adjusted		686	519
Residential loans transferred to the Bancorp's portfolio		28	288	31
Fair value changes included in earnings for instruments for which the fair value option was elected		6	17
Percentage of Vantiv Holding, LLC sold to Advent for cash and warrants					51.00%
Net Losses On Operating Lease Equipment		9	33
OTTI	[1]	16	5	$ 24
Larger commercial loans, subject to impairment review		1
Commercial Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Portfolio loans to loans held for sale		140	37
Existing loans held for sale, further adjusted		2	1
Net impact related to fair value adjustments		30	1
Gain Loss On Sales Of Loans Net			5
Residential Mortgagel Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Portfolio loans to loans held for sale		0	233
Net impact related to fair value adjustments			2
Other Real Estate Owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net impact related to fair value adjustments		9	10
Nonrecurring Losses Included As Charge-Offs		8	14
Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
OTTI		$ 9	$ 1
Vantiv Holding, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Vantiv Holding, LLC sold to Advent for cash and warrants					51.00%
Vantiv Holding, LLC Strike Price		$ 15.98
Exchange Of Class C Shares For Class A Shares			8.0
Vantiv Holding, LLC | Class C Units
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Warrant Exercised Total Shares Settled		5.7	5.4
Shares Exercised Underlying Warrant		7.8
Vantiv, Inc. | Class A Units
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Exchange Of Class C Shares For Class A Shares		5.7	5.4
Vantiv, Inc. | Class A Units | Shares Sold In Secondary Offering
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Warrant Exercised Total Shares Settled		4.8
Vantiv, Inc. | Class A Units | Shares repurchased by Vantiv Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Warrant Exercised Total Shares Settled		0.9
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Residential loans transferred to the Bancorp's portfolio			$ 55
Fair value adjustment			1
Fair value of loans		$ 2	$ 2

[1] (a) Included in securiti es gains, net, in the Consolidated Statements of Income .