Loans (Credit Quality Indicator At Amortized Cost By Origination Year) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	$ 7,843.0	$ 6,875.8
Loans originated, year two	3,122.0	3,905.4
Loans originated, year three	2,591.3	3,835.4
Loans originated, year four	2,759.6	3,176.8
Loans originated, year five	2,137.0	1,540.2
PRIOR	3,341.4	2,664.7
REVOLVING LOANS	19,439.0	20,656.1
REVOLVING LOANS CONVERTED TO TERM LOANS	715.0	736.2
TOTAL LOANS	41,948.3	43,390.6
Charge-offs, year one	(0.2)	0.0
Charge-offs, year two	0.0	(7.3)
Charge-offs, year three	0.0	(7.8)
Charge-offs, year four	(2.1)	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	(1.6)	(0.4)
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(3.9)	(15.5)	$ (7.5)
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	6,400.0	5,454.6
Loans originated, year two	1,999.8	2,764.1
Loans originated, year three	1,936.6	2,261.1
Loans originated, year four	1,459.7	1,624.2
Loans originated, year five	914.3	428.7
PRIOR	774.8	698.9
REVOLVING LOANS	6,819.3	6,948.9
REVOLVING LOANS CONVERTED TO TERM LOANS	126.5	98.3
TOTAL LOANS	20,431.0	20,278.8
Charge-offs, year one	0.0	0.0
Charge-offs, year two	0.0	(7.3)
Charge-offs, year three	0.0	(7.8)
Charge-offs, year four	(2.1)	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	(1.4)	0.0
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(3.5)	(15.1)	(5.7)
Commercial | Commercial and Institutional
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	957.4	1,205.2
Loans originated, year two	1,106.5	833.9
Loans originated, year three	492.4	826.2
Loans originated, year four	517.4	964.7
Loans originated, year five	352.7	166.8
PRIOR	268.8	423.7
REVOLVING LOANS	6,196.2	6,023.5
REVOLVING LOANS CONVERTED TO TERM LOANS	103.6	93.1
TOTAL LOANS	9,995.0	10,537.1
Charge-offs, year one	0.0	0.0
Charge-offs, year two	0.0	(7.3)
Charge-offs, year three	0.0	(5.4)
Charge-offs, year four	0.0	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	(1.4)	0.0
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(1.4)	(12.7)
Commercial | Commercial and Institutional | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	340.7	462.1
Loans originated, year two	425.1	238.2
Loans originated, year three	87.8	367.9
Loans originated, year four	220.3	466.2
Loans originated, year five	111.9	82.2
PRIOR	149.5	277.2
REVOLVING LOANS	4,294.6	4,364.8
REVOLVING LOANS CONVERTED TO TERM LOANS	57.6	26.5
TOTAL LOANS	5,687.5	6,285.1
Commercial | Commercial and Institutional | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	528.0	708.3
Loans originated, year two	661.5	506.4
Loans originated, year three	354.3	392.5
Loans originated, year four	263.7	428.3
Loans originated, year five	218.9	82.3
PRIOR	116.6	144.2
REVOLVING LOANS	1,844.1	1,585.1
REVOLVING LOANS CONVERTED TO TERM LOANS	35.7	59.7
TOTAL LOANS	4,022.8	3,906.8
Commercial | Commercial and Institutional | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	88.7	34.8
Loans originated, year two	19.9	89.3
Loans originated, year three	50.3	65.8
Loans originated, year four	33.4	70.2
Loans originated, year five	21.9	2.3
PRIOR	2.7	2.3
REVOLVING LOANS	57.5	73.6
REVOLVING LOANS CONVERTED TO TERM LOANS	10.3	6.9
TOTAL LOANS	284.7	345.2
Commercial | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1,137.1	747.3
Loans originated, year two	755.5	1,846.3
Loans originated, year three	1,412.7	1,420.5
Loans originated, year four	929.5	634.5
Loans originated, year five	561.6	191.3
PRIOR	219.9	218.5
REVOLVING LOANS	233.0	250.6
REVOLVING LOANS CONVERTED TO TERM LOANS	22.9	5.2
TOTAL LOANS	5,272.2	5,314.2
Charge-offs, year one	0.0	0.0
Charge-offs, year two	0.0	0.0
Charge-offs, year three	0.0	(2.4)
Charge-offs, year four	(2.1)	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	0.0	0.0
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(2.1)	(2.4)
Commercial | Commercial Real Estate | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	118.5	123.2
Loans originated, year two	98.7	256.3
Loans originated, year three	80.8	224.4
Loans originated, year four	52.6	203.7
Loans originated, year five	157.3	13.8
PRIOR	20.8	43.7
REVOLVING LOANS	37.9	52.6
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	566.6	917.7
Commercial | Commercial Real Estate | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	946.7	610.1
Loans originated, year two	654.8	1,574.2
Loans originated, year three	1,325.1	1,070.4
Loans originated, year four	831.4	424.8
Loans originated, year five	404.3	173.2
PRIOR	198.7	174.4
REVOLVING LOANS	195.1	198.0
REVOLVING LOANS CONVERTED TO TERM LOANS	22.9	5.2
TOTAL LOANS	4,579.0	4,230.3
Commercial | Commercial Real Estate | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	71.9	14.0
Loans originated, year two	2.0	15.8
Loans originated, year three	6.8	125.7
Loans originated, year four	45.5	6.0
Loans originated, year five	0.0	4.3
PRIOR	0.4	0.4
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	126.6	166.2
Commercial | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1,331.8	1,188.5
Loans originated, year two	137.8	83.9
Loans originated, year three	31.5	14.4
Loans originated, year four	12.8	25.0
Loans originated, year five	0.0	70.6
PRIOR	286.1	56.7
REVOLVING LOANS	390.1	674.8
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	2,190.1	2,113.9
Commercial | Non-U.S. | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	696.5	707.1
Loans originated, year two	119.2	0.0
Loans originated, year three	15.4	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	70.6
PRIOR	112.5	28.8
REVOLVING LOANS	258.6	614.9
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	1,202.2	1,421.4
Commercial | Non-U.S. | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	634.3	480.5
Loans originated, year two	18.6	83.9
Loans originated, year three	16.1	0.8
Loans originated, year four	0.0	25.0
Loans originated, year five	0.0	0.0
PRIOR	173.6	27.9
REVOLVING LOANS	131.5	59.9
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	974.1	678.0
Commercial | Non-U.S. | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1.0	0.9
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	13.6
Loans originated, year four	12.8	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	13.8	14.5
Commercial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	2,973.7	2,313.6
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	2,973.7	2,313.6
Commercial | Other | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1,730.0	1,142.4
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	1,730.0	1,142.4
Commercial | Other | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1,243.7	1,171.2
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	1,243.7	1,171.2
Personal
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1,443.0	1,421.2
Loans originated, year two	1,122.2	1,141.3
Loans originated, year three	654.7	1,574.3
Loans originated, year four	1,299.9	1,552.6
Loans originated, year five	1,222.7	1,111.5
PRIOR	2,566.6	1,965.8
REVOLVING LOANS	12,619.7	13,707.2
REVOLVING LOANS CONVERTED TO TERM LOANS	588.5	637.9
TOTAL LOANS	21,517.3	23,111.8
Charge-offs, year one	(0.2)	0.0
Charge-offs, year two	0.0	0.0
Charge-offs, year three	0.0	0.0
Charge-offs, year four	0.0	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	(0.2)	(0.4)
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(0.4)	(0.4)	$ (1.8)
Personal | Private Client
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	545.1	500.3
Loans originated, year two	697.0	710.2
Loans originated, year three	277.1	468.4
Loans originated, year four	372.2	428.4
Loans originated, year five	197.6	131.4
PRIOR	214.6	225.9
REVOLVING LOANS	11,667.6	12,755.6
REVOLVING LOANS CONVERTED TO TERM LOANS	579.2	628.6
TOTAL LOANS	14,550.4	15,848.8
Charge-offs, year one	0.0
Charge-offs, year two	0.0
Charge-offs, year three	0.0
Charge-offs, year four	0.0
Charge-offs, year five	0.0
Charge-offs, prior	(0.1)
Charge-offs, revolving loans	0.0
Charge-offs, revolving loans converted to term loans	0.0
Charge-offs	(0.1)
Personal | Private Client | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	144.9	251.3
Loans originated, year two	130.7	33.9
Loans originated, year three	133.0	84.4
Loans originated, year four	58.7	37.9
Loans originated, year five	46.6	7.9
PRIOR	33.3	44.6
REVOLVING LOANS	5,588.1	6,993.2
REVOLVING LOANS CONVERTED TO TERM LOANS	38.7	93.3
TOTAL LOANS	6,174.0	7,546.5
Personal | Private Client | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	400.2	249.0
Loans originated, year two	566.3	660.2
Loans originated, year three	128.9	384.0
Loans originated, year four	313.5	390.5
Loans originated, year five	151.0	123.5
PRIOR	181.3	181.3
REVOLVING LOANS	6,070.8	5,734.8
REVOLVING LOANS CONVERTED TO TERM LOANS	540.5	535.3
TOTAL LOANS	8,352.5	8,258.6
Personal | Private Client | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	0.0	0.0
Loans originated, year two	0.0	16.1
Loans originated, year three	15.2	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	8.7	27.6
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	23.9	43.7
Personal | Residential Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	608.9	411.9
Loans originated, year two	403.0	414.1
Loans originated, year three	364.8	1,090.7
Loans originated, year four	918.9	1,085.1
Loans originated, year five	1,001.7	980.1
PRIOR	2,330.9	1,714.2
REVOLVING LOANS	447.2	411.7
REVOLVING LOANS CONVERTED TO TERM LOANS	1.9	2.1
TOTAL LOANS	6,077.3	6,109.9
Charge-offs, year one	0.0	0.0
Charge-offs, year two	0.0	0.0
Charge-offs, year three	0.0	0.0
Charge-offs, year four	0.0	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	(0.1)	(0.1)
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(0.1)	(0.1)
Personal | Residential Real Estate | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	357.1	197.5
Loans originated, year two	138.8	150.5
Loans originated, year three	131.9	436.7
Loans originated, year four	343.3	375.2
Loans originated, year five	334.6	325.7
PRIOR	993.1	743.6
REVOLVING LOANS	232.3	114.3
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	2,531.1	2,343.5
Personal | Residential Real Estate | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	250.8	212.7
Loans originated, year two	264.2	263.6
Loans originated, year three	232.0	647.2
Loans originated, year four	567.5	706.0
Loans originated, year five	635.8	652.1
PRIOR	1,306.3	938.1
REVOLVING LOANS	194.4	270.2
REVOLVING LOANS CONVERTED TO TERM LOANS	1.9	2.1
TOTAL LOANS	3,452.9	3,692.0
Personal | Residential Real Estate | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	1.0	1.7
Loans originated, year two	0.0	0.0
Loans originated, year three	0.9	6.8
Loans originated, year four	8.1	3.9
Loans originated, year five	31.3	2.3
PRIOR	31.5	32.5
REVOLVING LOANS	20.5	27.2
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	93.3	74.4
Personal | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	56.8	30.6
Loans originated, year two	22.2	17.0
Loans originated, year three	12.8	15.2
Loans originated, year four	8.8	39.1
Loans originated, year five	23.4	0.0
PRIOR	21.1	25.7
REVOLVING LOANS	504.9	539.9
REVOLVING LOANS CONVERTED TO TERM LOANS	7.4	7.2
TOTAL LOANS	657.4	674.7
Personal | Non-U.S. | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	5.1	3.3
Loans originated, year two	0.0	1.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.6	0.0
PRIOR	11.4	6.0
REVOLVING LOANS	224.7	369.6
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	241.8	379.9
Personal | Non-U.S. | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	29.1	19.5
Loans originated, year two	14.6	16.0
Loans originated, year three	12.8	15.2
Loans originated, year four	8.8	39.1
Loans originated, year five	22.8	0.0
PRIOR	9.6	19.6
REVOLVING LOANS	280.2	170.3
REVOLVING LOANS CONVERTED TO TERM LOANS	7.4	7.2
TOTAL LOANS	385.3	286.9
Personal | Non-U.S. | 6 to 9 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	22.6	7.8
Loans originated, year two	7.6	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.1	0.1
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	30.3	7.9
Personal | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	232.2	478.4
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	232.2	478.4
Charge-offs, year one	(0.2)	0.0
Charge-offs, year two	0.0	0.0
Charge-offs, year three	0.0	0.0
Charge-offs, year four	0.0	0.0
Charge-offs, year five	0.0	0.0
Charge-offs, prior	0.0	(0.3)
Charge-offs, revolving loans	0.0	0.0
Charge-offs, revolving loans converted to term loans	0.0	0.0
Charge-offs	(0.2)	(0.3)
Personal | Other | 1 to 3 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	86.0	168.5
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	86.0	168.5
Personal | Other | 4 to 5 Category
Financing Receivable, Credit Quality Indicator [Line Items]
Loans originated, year one	146.2	309.9
Loans originated, year two	0.0	0.0
Loans originated, year three	0.0	0.0
Loans originated, year four	0.0	0.0
Loans originated, year five	0.0	0.0
PRIOR	0.0	0.0
REVOLVING LOANS	0.0	0.0
REVOLVING LOANS CONVERTED TO TERM LOANS	0.0	0.0
TOTAL LOANS	$ 146.2	$ 309.9