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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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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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Amount of 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.

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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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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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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of realized gain (loss) on investment.

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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
Securities (Narrative) (Details) $ in Millions	Jan. 31, 2024 USD ($)	Nov. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) security	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) security	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) security
Debt and Equity Securities, FV-NI [Line Items]
Number of securities in an unrealized loss position \| security			693		693		898
Total fair value			$ 18,132.8		$ 18,132.8		$ 19,435.3
Debt securities, unrealized losses			243.9		243.9		568.3
Investment security gains (losses)	$ (189.4)	$ (176.4)	0.0	$ 0.0	(189.3)	$ 6.9
Provision for (release of) credit losses			8.4	14.6	8.5	14.1
Held to maturity securities			22,708.6		22,708.6		26,221.7
Debt securities, held-to-maturity, accumulated unrecognized loss			$ 1,347.2		$ 1,347.2		$ 1,755.6
Percentage of debt securities, held-to-maturity, portfolio			1		1		1
Proceeds from sale of investment securities			$ 0.0	17.1	$ 2,000.0	2,200.0
Realized investment gains (losses)			$ 0.0	0.0	$ (189.3)	6.9
Moodys And Standard Poors A Or Higher Rating
Debt and Equity Securities, FV-NI [Line Items]
Percentage of debt securities, held-to-maturity, portfolio			0.96		0.96		0.97
BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities			$ 337.1		$ 337.1		$ 334.0
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			$ 575.5		$ 575.5		$ 560.9
Percentage of debt securities, held-to-maturity, portfolio			0.03		0.03		0.02
Government Sponsored Agency
Debt and Equity Securities, FV-NI [Line Items]
Total fair value			$ 8,705.1		$ 8,705.1		$ 9,817.6
Debt securities, unrealized losses			114.3		114.3		200.3
Held to maturity securities			8,826.8		8,826.8		9,355.3
Debt securities, held-to-maturity, accumulated unrecognized loss			823.8		823.8		1,012.4
Realized investment gains (losses)			0.0	0.0	(23.0)	0.0
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
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds
Debt and Equity Securities, FV-NI [Line Items]
Total fair value			1,562.9		1,562.9		2,477.0
Debt securities, unrealized losses			45.6		45.6		105.8
Held to maturity securities			5,062.1		5,062.1		5,245.5
Debt securities, held-to-maturity, accumulated unrecognized loss			197.6		197.6		294.9
Realized investment gains (losses)			0.0	0.0	(48.2)	0.0
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
U.S. Government
Debt and Equity Securities, FV-NI [Line Items]
Total fair value			5,923.9		5,923.9		3,364.7
Debt securities, unrealized losses			19.1		19.1		61.5
Realized investment gains (losses)			0.0	0.0	(34.8)	0.0
Other Asset-Backed
Debt and Equity Securities, FV-NI [Line Items]
Total fair value			476.3		476.3		2,018.5
Debt securities, unrealized losses			14.2		14.2		100.0
Held to maturity securities			111.6		111.6		214.2
Debt securities, held-to-maturity, accumulated unrecognized loss			0.2		0.2		0.2
Realized investment gains (losses)			0.0	0.0	(56.5)	(0.8)
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
Corporate Debt
Debt and Equity Securities, FV-NI [Line Items]
Total fair value			104.5		104.5		147.4
Debt securities, unrealized losses			2.4		2.4		2.2
Provision for (release of) credit losses			(0.4)	(0.6)	(1.0)	(0.6)
Net amount of recognized liabilities for repurchase agreements			0.2		0.2		1.2
Held to maturity securities			491.1		491.1		646.1
Debt securities, held-to-maturity, accumulated unrecognized loss			14.7		14.7		28.2
Realized investment gains (losses)			0.0	$ 0.0	0.0	$ (1.2)
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
Other
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities			600.8		600.8		576.3
Debt securities, held-to-maturity, accumulated unrecognized loss			156.9		156.9		147.0
Other \| BBB
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities			0.0		0.0		0.0
Other \| NOT RATED
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity securities			$ 546.1		$ 546.1		$ 521.5