Related Party (Summary of Vantiv Holding, LLC Sales Transactions) (Detail) - USD ($) $ in Millions		3 Months Ended												12 Months Ended
		Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2015	Jun. 30, 2014		Sep. 30, 2013		Jun. 30, 2013		Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2009
Related Party Transactions
Gain on sale of Worldpay, Inc. shares		$ 205	$ 414											$ 205	$ 1,037	$ 0
Equity Method Investment, Ownership Percentage	[1]	3.30%	4.90%														8.60%
Worldpay Holding, LLC
Related Party Transactions
Gain on sale of Worldpay, Inc. shares				$ 331	$ 125		$ 85		$ 242		$ 157		$ 115
Equity Method Investment, Ownership Percentage				18.30%	22.80%	[1]	25.10%	[1]	27.70%	[1]	33.10%	[1]	39.00%	3.30%				49.00%

[1] (a) The Bancorp’s remaining investment in Worldpay Holding, LLC of $ 420 as of December 31, 2018 was accounted for as an equity method investment in the Bancorp’s Consolidated Financial Statements.