Credit Loss, Excluding Accrued Interest, Expense (Reversal)

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- Definition

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

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No definition available.

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- Definition

Held To Maturity Securities, Transferred From Available For Sale

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- Definition

Number of Securities, Unrealized Losses Position

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No definition available.

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- Definition

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

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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- Definition

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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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

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).

+ References

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- Definition

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).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

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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-Topic 320
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- Definition

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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- Definition

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.

+ References

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- Definition

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
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- Definition

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

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- Definition

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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No definition available.

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Securities (Narrative) (Details) $ in Millions	3 Months Ended		11 Months Ended	12 Months Ended
Securities (Narrative) (Details) $ in Millions	Dec. 31, 2023 USD ($) investment	Mar. 31, 2023 USD ($)	Nov. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) investment	Dec. 31, 2022 USD ($) investment	Dec. 31, 2021 USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Number of securities in an unrealized loss position \| investment	898			898	1,030
Debt securities, available-for-sale, unrealized loss position	$ 19,435.3			$ 19,435.3	$ 21,434.8
Debt securities, available-for-sale, unrealized loss position, accumulated loss	568.3			568.3	1,049.2
Debt securities, available-for-sale, accumulated gross unrealized loss	582.4			582.4	1,067.8
Available for sale	23,089.8			23,089.8	26,699.9
Debt securities, available-for-sale, realized loss			$ (176.4)	180.0	214.0	$ 1.7
Available for sale, amortized cost	23,659.0			23,659.0	27,760.0
Allowance for credit losses, available-for-sale securities	1.2			1.2	1.3
Credit loss, excluding accrued interest, expense (reversal)				24.6	10.7	(81.5)
Debt securities, held-to-maturity, amortized cost	26,221.7			26,221.7	25,036.1
Debt securities, held-to-maturity, accumulated unrecognized Loss	$ 1,755.6			$ 1,755.6	2,158.2
Transferred from available for sale to held to maturity					$ 6,600.0
Percentage of debt securities, held-to-maturity, portfolio	1			1	1
Investment security gains (losses), net	$ 176.4	$ (6.9)		$ 169.5	$ 214.0	0.3
Gross proceeds from sale of securities					$ 138.7	$ 116.7
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
Moodys And Standard Poors Not Rated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, amortized cost	$ 560.9			$ 560.9	$ 502.7
Percentage of debt securities, held-to-maturity, portfolio					0.02
Government Sponsored Agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale, unrealized loss position	9,817.6			9,817.6	$ 10,369.1
Debt securities, available-for-sale, unrealized loss position, accumulated loss	200.3			200.3	351.6
Debt securities, available-for-sale, accumulated gross unrealized loss	200.3			200.3	351.6
Available for sale	11,553.0			11,553.0	11,545.2
Available for sale, amortized cost	11,744.3			11,744.3	11,892.5
Debt securities, held-to-maturity, amortized cost	9,355.3			9,355.3	9,407.7
Debt securities, held-to-maturity, accumulated unrecognized Loss	1,012.4			1,012.4	1,076.0
Government Sponsored Agency \| Moodys And Standard Poors Not Rated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, amortized cost	0.0			0.0	0.0
Corporate Debt
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale, unrealized loss position	147.4			147.4	557.6
Debt securities, available-for-sale, unrealized loss position, accumulated loss	2.2			2.2	17.4
Debt securities, available-for-sale, accumulated gross unrealized loss	8.1			8.1	26.9
Available for sale	279.5			279.5	1,747.6
Available for sale, amortized cost	287.5			287.5	1,774.3
Credit loss, excluding accrued interest, expense (reversal)				(0.1)	1.3
Debt securities, held-to-maturity, amortized cost	646.1			646.1	713.3
Debt securities, held-to-maturity, accumulated unrecognized Loss	28.2			28.2	45.4
Gross proceeds from sale of securities				5,200.0
Corporate Debt \| Moodys And Standard Poors Not Rated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, amortized cost	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, available-for-sale, unrealized loss position	2,477.0			2,477.0	2,112.5
Debt securities, available-for-sale, unrealized loss position, accumulated loss	105.8			105.8	157.6
Debt securities, available-for-sale, accumulated gross unrealized loss	114.0			114.0	166.7
Available for sale	2,899.9			2,899.9	2,479.4
Available for sale, amortized cost	3,013.8			3,013.8	2,645.8
Debt securities, held-to-maturity, amortized cost	5,245.5			5,245.5	5,703.3
Debt securities, held-to-maturity, accumulated unrecognized Loss	294.9			294.9	436.1
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds \| Moodys And Standard Poors Not Rated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, amortized cost	0.0			0.0	0.0
Covered Bonds
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale, unrealized loss position	213.2			213.2	280.8
Debt securities, available-for-sale, unrealized loss position, accumulated loss	9.7			9.7	14.7
Debt securities, available-for-sale, accumulated gross unrealized loss	9.7			9.7	14.7
Available for sale	347.1			347.1	388.7
Available for sale, amortized cost	356.8			356.8	403.1
Debt securities, held-to-maturity, amortized cost	2,208.6			2,208.6	2,530.3
Debt securities, held-to-maturity, accumulated unrecognized Loss	108.3			108.3	158.7
Covered Bonds \| Moodys And Standard Poors Not Rated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, amortized cost	$ 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			3,000.0		2,100.0
Available for sale, amortized cost			$ 3,200.0
Investment security gains (losses), net					$ 213.0