Shareholders' Equity - Comprehensive Capital Plan (Details) - USD ($) $ / shares in Units, shares in Millions			3 Months Ended				12 Months Ended
		Sep. 10, 2021	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common shares repurchased, value							$ 559,000,000	$ 134,000,000	$ 835,000,000
Accelerated Share Repurchase Program, Common Stock Repurchased	[1]						(585,000,000)
Cash payment for ASR program							$ 559,000,000	$ 134,000,000	$ 835,000,000
Cash dividends declared per common share (in dollars per share)			$ 0.195	$ 0.185	$ 0.185	$ 0.185	$ 0.75	$ 0.74	$ 0.71
Treasury Stock, at Cost
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common shares repurchased, value							$ 559,000,000	$ 134,000,000	$ 835,000,000
Accelerated Share Repurchase Program, Common Stock Repurchased	[1]						(585,000,000)
2021 Repurchase Authorization
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Authorized amount of share repurchases			$ 1,500,000,000				1,500,000,000
Common shares repurchased, value							710,000,000
2020 Capital Plan Authorization
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common shares repurchased, value							$ 466,000,000
Open Market Share Repurchases
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common shares repurchased, value		$ 559,000,000
Employee Equity Compensation Programs
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common shares repurchased, value		32,000,000
ASR Share Repurchase Program
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash payment for ASR program		$ 585,000,000
Initial shares repurchased		23.6
Initial price per share (in dollars per share)		$ 19.87
Reduction to capital surplus balance				$ 117,000,000
Final shares repurchased		2.5
Average price per share (in dollars per share)		$ 22.48
Share purchased between up front delivery and final settlement		26.0

[1] See Note 24 (“Shareholders' Equity”) for additional detail regarding ASR program.