Goodwill (Changes in the Net Carrying Amount of Goodwill by Reporting Segment) (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019		Dec. 31, 2018	Mar. 22, 2019	Dec. 31, 2016
Goodwill
Goodwill				$ 1,800	$ 3,410
Accumulated impairment losses					(965)
Goodwill Roll Forward
Net carrying value, beginning of period:	$ 2,478		$ 2,445
Acquisition activity	1,843		33
Net carrying value, end of period:	4,321		2,478
Commercial Banking
Goodwill
Goodwill					1,363
Accumulated impairment losses					(750)
Goodwill Roll Forward
Net carrying value, beginning of period:	630		613
Acquisition activity	0		17
Net carrying value, end of period:	630		630
Branch Banking
Goodwill
Goodwill					1,655
Accumulated impairment losses					0
Goodwill Roll Forward
Net carrying value, beginning of period:	1,655		1,655
Acquisition activity	0		0
Net carrying value, end of period:	1,655		1,655
Consumer Lending
Goodwill
Goodwill					215
Accumulated impairment losses					(215)
Goodwill Roll Forward
Net carrying value, beginning of period:	0		0
Acquisition activity	0		0
Net carrying value, end of period:	0		0
Wealth and Asset Management
Goodwill
Goodwill					177
Accumulated impairment losses					0
Goodwill Roll Forward
Net carrying value, beginning of period:	193		177
Acquisition activity	0		16
Net carrying value, end of period:	193		193
General Corporate and Other
Goodwill
Goodwill					0
Accumulated impairment losses					$ 0
Goodwill Roll Forward
Net carrying value, beginning of period:	0		0
Acquisition activity	1,843		0
Net carrying value, end of period:	$ 1,843	[1]	$ 0

[1] Due to the timing of the MB Financial, Inc. acquisition, the Bancorp is in the process of completing its analysis of the allocatio n of the goodwill across its four business segments, therefore goodwill is presented as part of General Corporate and Ot her as of March 31, 2019 .