Capital Actions - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended							3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Preferred stock Series G	Jun. 30, 2013 Preferred stock Series G	Dec. 31, 2012 Preferred stock Series G	Sep. 30, 2013 5.10% fixed-to-floating rate non-cumulative Series H perpetual preferred stock	Jun. 30, 2013 5.10% fixed-to-floating rate non-cumulative Series H perpetual preferred stock	Mar. 31, 2013 November 6, 2012 ASR	Dec. 31, 2012 November 6, 2012 ASR	Mar. 31, 2013 December 14, 2012 ASR	Dec. 31, 2012 December 14, 2012 ASR	Mar. 31, 2013 January 28, 2013 ASR	Sep. 30, 2013 May 21, 2013 ASR	Sep. 30, 2012 August 2012 Repurchase Program [Member]	Mar. 31, 2013 March 2013 Repurchase Program [Member]
Capital Actions
Redemption of common shares										7,710,761		6,267,410	6,953,028	25,035,519
Shares acquired for treasury	$ 600	$ (664)	$ (425)							$ 125		$ 100	$ 125	$ 539
Incremental common shares									657,914		127,760		849,037	4,270,250
Repurchase Shares Authorized															100,000,000	100,000,000
Redemption date										Nov. 09, 2012		Dec. 19, 2012	Jan. 31, 2013
Forward contract redemption date									Feb. 12, 2013		Feb. 27, 2013		Apr. 05, 2013	Oct. 01, 2013
Depository shares								600,000
Preferred Stock Issuance								24,000
Issuance of preferred shares		593
Amount of preferred stock available for issuance		$ 450
Preferred stock, liquidation preference						$ 25,000	$ 25,000
Preferred Stock, Dividend Payment Terms		The preferred stock accrues dividends, on a non-cumulative, semi-annual basis, at an annual rate of 5.10% through but excluding June 30, 2023, at which time it converts to a quarterly floating rate dividend of three-month LIBOR plus 3.033%
Preferred Stock, Redemption Terms		Subject to any required regulatory approval, the Bancorp may redeem the Series H preferred shares at its option in whole or in part, at any time on or after June 30, 2023 and following a regulatory capital event at any time prior to June 30, 2023
Preferred Stock Conversion Date					Jul. 01, 2013
Preferred Stock Conversion				16,442
Preferred stock, outstanding						16,450	24,000
Depository Shares				4,110,500
Fifth Third Bank Common Stock Conversion Factor		2,159.8272
Common Stock Issued		35,511,740