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Debt Securities, Held-To-Maturity, Percent Of Portfolio

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Number of Securities, Unrealized Losses Position

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The cash inflow associated with the sales of investment securities (available for sale and held to maturity).

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Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Name Accounting Standards Codification
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-Publisher FASB
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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
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-Name Accounting Standards Codification
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-Paragraph 1
-Publisher FASB
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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Securities (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Securities (Narrative) (Details) $ in Millions	Jan. 31, 2023 USD ($)	Sep. 30, 2023 USD ($) investment	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) investment	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) investment
Debt and Equity Securities, FV-NI [Line Items]
Number of securities in an unrealized loss position \| investment		1,044		1,044		1,030
Debt securities, unrealized losses		$ 906.2		$ 906.2		$ 1,049.2
Debt securities, available-for-sale, realized loss						213.0
Available for Sale		24,342.1		24,342.1		26,699.9
Debt securities, available-for-sale, realized gain	$ 6.9
Provision for credit losses		14.6	$ 1.4	14.1	$ 6.2
Held to maturity securities		24,920.4		24,920.4		25,036.1
Debt securities, held-to-maturity, accumulated unrecognized loss		$ 2,473.6		$ 2,473.6		$ 2,158.2
Percentage of debt securities, held-to-maturity, portfolio		1		1		1
Investment Security Gains (Losses), net		$ 0.0	0.3	$ (6.9)	0.3
Moodys And Standard Poors A Or Higher Rating
Debt and Equity Securities, FV-NI [Line Items]
Percentage of debt securities, held-to-maturity, portfolio		0.97		0.97		0.97
BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		$ 320.1		$ 320.1		$ 323.4
Percentage of debt securities, held-to-maturity, portfolio		0.01		0.01		0.01
NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		$ 563.6		$ 563.6		$ 502.7
Percentage of debt securities, held-to-maturity, portfolio		0.02		0.02		0.02
Government Sponsored Agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		$ 338.1		$ 338.1		$ 351.6
Available for Sale		11,656.8		11,656.8		11,545.2
Held to maturity securities		9,159.9		9,159.9		9,407.7
Debt securities, held-to-maturity, accumulated unrecognized loss		1,405.6		1,405.6		1,076.0
Government Sponsored Agency \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Government Sponsored Agency \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Obligations of States and Political Subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		19.4		19.4		30.2
Available for Sale		282.1		282.1		787.6
Held to maturity securities		2,577.7		2,577.7		2,565.3
Debt securities, held-to-maturity, accumulated unrecognized loss		177.9		177.9		149.8
Obligations of States and Political Subdivisions \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Obligations of States and Political Subdivisions \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Corporate Debt
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		10.2		10.2		17.4
Available for Sale		380.9		380.9		1,747.6
Provision for credit losses		(0.6)	(0.9)	(0.6)	0.8
Net amount of recognized liabilities for repurchase agreements		0.7		0.7		1.3
Held to maturity securities		639.1		639.1		713.3
Debt securities, held-to-maturity, accumulated unrecognized loss		38.0		38.0		45.4
Proceeds from sale of investment securities		17.1	$ 100.2	2,200.0	$ 100.2
Corporate Debt \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Corporate Debt \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		140.4		140.4		157.6
Available for Sale		2,959.8		2,959.8		2,479.4
Held to maturity securities		5,443.8		5,443.8		5,703.3
Debt securities, held-to-maturity, accumulated unrecognized loss		400.3		400.3		436.1
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		1.1		1.1		1.1
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Available For Sale, Debt Securities, Portfolio For Sale
Debt and Equity Securities, FV-NI [Line Items]
Available for Sale						2,100.0
Commercial Mortgage-Backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		64.7		64.7		69.2
Available for Sale		884.3		884.3		1,387.8
Held to maturity securities		37.6		37.6
Debt securities, held-to-maturity, accumulated unrecognized loss		0.7		0.7
Commercial Mortgage-Backed \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0
Commercial Mortgage-Backed \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0
Other Asset-Backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, unrealized losses		195.6		195.6		288.1
Available for Sale		4,771.5		4,771.5		5,256.2
Held to maturity securities		246.6		246.6		263.7
Debt securities, held-to-maturity, accumulated unrecognized loss		0.2		0.2		1.0
Other Asset-Backed \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		0.0		0.0		0.0
Other Asset-Backed \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities		$ 0.0		$ 0.0		$ 0.0