Commitments, Contingent Liabilities and Guarantees - Additional Information (Details) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2019	Jun. 30, 2018	Sep. 30, 2014	Sep. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2008
Loss Contingencies
Margin account balance held by the brokerage clearing agent	$ 27,000,000		$ 27,000,000		$ 14,000,000
Visa
Loss Contingencies
Fair value of liability	213,000,000		213,000,000		201,000,000
Visa IPO, shares of Visa's Class B common stock received														10.1
Visa Class B shares carryover basis														$ 0
Escrow deposit						$ 300,000,000	$ 600,000,000	$ 450,000,000	$ 150,000,000	$ 1,565,000,000	$ 400,000,000	$ 800,000,000	$ 500,000,000	$ 3,000,000,000
Residential mortgage loans
Loss Contingencies
Fair value of liability	11,000,000		11,000,000
Repurchased outstanding principal	9,000,000	$ 7,000,000	19,000,000	$ 13,000,000
Make-whole payments			1,000,000
Repurchase demand request	18,000,000	$ 9,000,000	28,000,000	$ 19,000,000
Outstanding repurchase demand inventory	11,000,000		11,000,000		5,000,000
Secured Debt
Loss Contingencies
Fully and unconditionally guaranteed certain long-term borrowing obligations issued by wholly-owned issuing trust entities	62,000,000		62,000,000		62,000,000
Standby Letters of Credit
Loss Contingencies
Reserve for unfunded commitments	$ 25,000,000		$ 25,000,000		$ 27,000,000
Standby letters of credit as a percentage of total letters of credit	99.00%		99.00%		99.00%
Standby Letters of Credit | Secured Debt
Loss Contingencies
Standby letters of credit as a percentage of total letters of credit	72.00%		72.00%		68.00%
Variable Rate Demand Note
Loss Contingencies
Total variable rate demand notes	$ 485,000,000		$ 485,000,000		$ 385,000,000
Fifth Third Securities, Inc. (FTS) acted as the remarketing agent to issuers of VRDNs	485,000,000		485,000,000		385,000,000
Letters of credit issued related to variable rate demand notes	138,000,000		138,000,000		142,000,000
Variable Rate Demand Note | Trading Securities
Loss Contingencies
Total variable rate demand notes	0		0		0
Other Liabilities
Loss Contingencies
Reserve for unfunded commitments	189,000,000		189,000,000		172,000,000
Other Liabilities | Residential mortgage loans
Loss Contingencies
Outstanding balances on residential mortgage loans sold with representation and warranty provisions	$ 9,000,000		$ 9,000,000		$ 8,000,000