Regulatory Capital and Other Regulatory Matters (Common Share Repurchases) (Details)			3 Months Ended					12 Months Ended	81 Months Ended
		Apr. 14, 2023 $ / shares	Mar. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Sep. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2022 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2023 $ / shares shares	Feb. 28, 2023 USD ($)	Jan. 10, 2022 USD ($)	Dec. 31, 2021 $ / shares shares	Jun. 30, 2016 shares
Accelerated Share Repurchases [Line Items]
Dividends declared (in dollars per share) | $ / shares			$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30			$ 0.25
Stock repurchased during period, value			$ 27,000,000	$ 51,000,000	$ 415,000,000	$ 600,000,000	$ 584,000,000
Common stock, share reduction									38.00%
Common stock, shares outstanding (in shares) | shares			300,820,617	299,324,357	300,335,000	312,781,000	327,306,000	299,324,357	300,820,617			337,941,000	484,000,000
Minimum capital conservation buffer			0.025						0.025
Stock repurchased during period, number of shares (in share) | shares			836,000	1,731,000	12,468,000	15,031,000	12,548,000
Cash dividends declared per common share (in dollars per share) | $ / shares	[1]		$ 0.30				$ 0.30
Unsecured debt
Accelerated Share Repurchases [Line Items]
Proceeds from issuance of subordinated long-term debt										$ 500,000,000
Subsequent event
Accelerated Share Repurchases [Line Items]
Cash dividends declared per common share (in dollars per share) | $ / shares		$ 0.30
Common stock
Accelerated Share Repurchases [Line Items]
Stock repurchase program, authorized amount											$ 2,000,000,000
Stock repurchased during period, value								$ 1,650,000,000

[1] Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers.