AOCI Attributable To Parent, After Tax [Abstract]

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AOCI Attributable To Parent, Before Tax [Abstract]

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AOCI Attributable To Parent, Tax [Abstract]

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss).

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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.

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Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).

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Accumulated Other Comprehensive Income (Loss) (Details of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2026	Jun. 30, 2025
AOCI Attributable To Parent, Before Tax [Abstract]
Net Change	$ 122.6		$ (5.3)		$ 77.7	$ 66.9
AOCI Attributable To Parent, Tax [Abstract]
Net Change	(37.7)		45.6		(38.9)	47.9
AOCI Attributable To Parent, After Tax [Abstract]
Other Comprehensive Income (Loss)	84.9	$ (46.1)	40.3	$ 74.5	38.8	114.8
Available for Sale Debt Securities
AOCI Attributable To Parent, Before Tax [Abstract]
Gains (Losses)	5.4		37.9		(80.9)	109.1
Net Change	102.0		63.6		40.2	159.6
AOCI Attributable To Parent, Tax [Abstract]
Gains (Losses)	(3.3)		(11.4)		19.8	(30.3)
Net Change	(29.3)		(17.7)		(12.1)	(42.7)
AOCI Attributable To Parent, After Tax [Abstract]
Gains (Losses)	2.1		26.5		(61.1)	78.8
Other Comprehensive Income (Loss)	72.7		45.9		28.1	116.9
Interest Income on Debt Securities
AOCI Attributable To Parent, Before Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	22.7		25.7		47.2	50.5
AOCI Attributable To Parent, Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(5.7)		(6.3)		(11.6)	(12.4)
AOCI Attributable To Parent, After Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	17.0		19.4		35.6	38.1
Net Losses on Debt Securities
AOCI Attributable To Parent, Before Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	73.9		0.0		73.9	0.0
AOCI Attributable To Parent, Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(20.3)		0.0		(20.3)	0.0
AOCI Attributable To Parent, After Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	53.6		0.0			0.0
Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable To Parent, Before Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(8.5)		(3.4)		(21.9)	(13.9)
Net Change	(2.4)		(0.2)		(9.4)	(0.9)
AOCI Attributable To Parent, Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	2.8		0.8		6.9	3.4
Net Change	0.7		0.1		2.4	0.3
AOCI Attributable To Parent, After Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(5.7)		(2.6)		(15.0)	(10.5)
Other Comprehensive Income (Loss)	(1.7)		(0.1)		(7.0)	(0.6)
Unrealized Gains (Losses) on Cash Flow Hedges \| Foreign Exchange Contracts
AOCI Attributable To Parent, Before Tax [Abstract]
Gains (Losses)	6.1		3.2		12.5	13.0
AOCI Attributable To Parent, Tax [Abstract]
Gains (Losses)	(2.1)		(0.7)		(4.5)	(3.1)
AOCI Attributable To Parent, After Tax [Abstract]
Gains (Losses)	4.0		2.5		8.0	9.9
Foreign Currency Adjustments
AOCI Attributable To Parent, Before Tax [Abstract]
Net Change	16.6		(71.7)		39.0	(94.4)
AOCI Attributable To Parent, Tax [Abstract]
Net Change	(7.6)		64.0		(28.4)	91.4
AOCI Attributable To Parent, After Tax [Abstract]
Other Comprehensive Income (Loss)	9.0		(7.7)		10.6	(3.0)
Foreign Currency Translation Adjustments
AOCI Attributable To Parent, Before Tax [Abstract]
Net Change	(14.6)		206.0		(77.2)	297.4
AOCI Attributable To Parent, Tax [Abstract]
Net Change	0.0		(4.3)		0.0	(4.9)
AOCI Attributable To Parent, After Tax [Abstract]
Other Comprehensive Income (Loss)	(14.6)		201.7		(77.2)	292.5
Long-Term Intra-Entity Foreign Currency Transaction Gains (Losses)
AOCI Attributable To Parent, Before Tax [Abstract]
Net Change	0.5		0.4		0.9	0.6
AOCI Attributable To Parent, Tax [Abstract]
Net Change	0.0		0.0		0.0	0.0
AOCI Attributable To Parent, After Tax [Abstract]
Other Comprehensive Income (Loss)	0.5		0.4		0.9	0.6
Net Investment Hedge Gains (Losses)
AOCI Attributable To Parent, Before Tax [Abstract]
Net Change	30.7		(278.1)		115.3	(392.4)
AOCI Attributable To Parent, Tax [Abstract]
Net Change	(7.6)		68.3		(28.4)	96.3
AOCI Attributable To Parent, After Tax [Abstract]
Other Comprehensive Income (Loss)	23.1		(209.8)		86.9	(296.1)
Pension and Other Postretirement Benefit Adjustments
AOCI Attributable To Parent, Before Tax [Abstract]
Gains (Losses)	(0.3)		0.0		(5.7)	(3.4)
Net Change	6.4		3.0		7.9	2.6
AOCI Attributable To Parent, Tax [Abstract]
Gains (Losses)	0.1		(0.1)		2.5	0.3
Net Change	(1.5)		(0.8)		(0.8)	(1.1)
AOCI Attributable To Parent, After Tax [Abstract]
Gains (Losses)	(0.2)		(0.1)		(3.2)	(3.1)
Other Comprehensive Income (Loss)	4.9		2.2		7.1	1.5
Amortization of Net Actuarial Loss
AOCI Attributable To Parent, Before Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	6.4		3.0		12.8	6.0
AOCI Attributable To Parent, Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(1.5)		(0.7)		(3.1)	(1.4)
AOCI Attributable To Parent, After Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	4.9		2.3		9.7	4.6
Amortization of Prior Service Cost (Credit)
AOCI Attributable To Parent, Before Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	0.3		0.0		0.8	0.0
AOCI Attributable To Parent, Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	(0.1)		0.0		(0.2)	0.0
AOCI Attributable To Parent, After Tax [Abstract]
Reclassification Adjustments for (Gains) Losses Included in Net Income	$ 0.2		$ 0.0		$ 0.6	$ 0.0