Common, Preferred and Treasury Stock (Common, Preferred, and Treasury Stock - Additional Information) (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 26, 2019	Jun. 30, 2018
Issuance of preferred stock		$ 242,000,000	$ 0	$ 0
Stock Repurchase Authorization Amount	$ 1,240,000,000	1,651,000,000	$ 1,810,000,000			$ 1,161,000,000
BHC stress test threshold	250,000,000,000	$ 250,000,000,000
Capital Distribution	$ 2,000,000,000
Stock Option, Exercise Price, Increase		$ 0.03
Preferred stock, Series J
Depositary shares		300,000
Preferred stock, issued		12,000
Issuance of preferred stock		$ 297,000,000
Preferred stock, liquidation preference		$ 25,000
Preferred Stock, Dividend Payment Terms		The preferred stock accrued dividends, on a non-cumulative semi-annual basis, at an annual rate of 4.90% through but excluding September 30, 2019, at which time it converted to a quarterly floating-rate dividend of three-month LIBOR plus 3.129%.
Preferred Stock, Redemption Terms		Subject to any required regulatory approval, the Bancorp may redeem the Series J preferred shares at its option, in whole or in part, at any time on or after September 30, 2019, or any time prior following a regulatory capital event.
Preferred stock, issued		12,000
Preferred stock, Series I
Depositary shares		18,000,000
Preferred stock, issued		18,000
Issuance of preferred stock		$ 441,000,000
Preferred stock, liquidation preference		$ 25,000
Preferred Stock, Dividend Payment Terms		The preferred stock accrues dividends, on a non-cumulative quarterly basis, at an annual rate of 6.625% through but excluding December 31, 2023, at which time it converts to a quarterly floating-rate dividend of three-month LIBOR plus 3.71%.
Preferred Stock, Redemption Terms		Subject to any required regulatory approval, the Bancorp may redeem the Series I preferred shares at its option in whole or in part, at any time on or after December 31, 2023 and may redeem in whole but not in part, following a regulatory capital event at any time prior to December 31, 2023.
Preferred stock, issued		18,000
Preferred stock, Series H
Depositary shares		600,000
Preferred stock, issued		24,000
Issuance of preferred stock		$ 593,000,000
Preferred stock, liquidation preference		$ 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 may redeem in whole but not in part, following a regulatory capital event at any time prior to June 30, 2023.
Preferred stock, issued		24,000
Preferred Stock Series K
Depositary shares		10,000,000
Preferred stock, issued		10,000
Issuance of preferred stock		$ 242,000,000
Preferred stock, liquidation preference		$ 25,000
Preferred stock, issued		10,000
Preferred Class B [Member]
Preferred stock, issued					200,000
Preferred stock, liquidation preference		$ 1,000
Preferred stock, issued					200,000
June 2019 Repurchase Program [Member]
Repurchase Shares Authorized		100,000,000