Reporting Segments and Related Information - Performance by Reporting Segment (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 155,508.4	$ 150,783.1	$ 155,036.7
TOTAL REVENUE	8,290.4	6,773.5	6,761.2
INCOME BEFORE INCOME TAXES	2,659.5	1,464.8	1,766.3
NET INCOME	$ 2,031.1	$ 1,107.3	$ 1,336.0
TOTAL ASSETS \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
TOTAL REVENUE \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
INCOME BEFORE INCOME TAXES \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
NET INCOME \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
Non-U.S.
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 43,173.2	$ 39,661.5	$ 35,991.3
TOTAL REVENUE	2,244.5	2,156.1	2,273.3
INCOME BEFORE INCOME TAXES	569.2	473.7	560.9
NET INCOME	$ 429.9	$ 354.0	$ 420.2
Non-U.S. \| TOTAL ASSETS \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	28.00%	26.00%	23.00%
Non-U.S. \| TOTAL REVENUE \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	27.00%	32.00%	34.00%
Non-U.S. \| INCOME BEFORE INCOME TAXES \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	21.00%	32.00%	32.00%
Non-U.S. \| NET INCOME \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	21.00%	32.00%	31.00%
U.S.
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 112,335.2	$ 111,121.6	$ 119,045.4
TOTAL REVENUE	6,045.9	4,617.4	4,487.9
INCOME BEFORE INCOME TAXES	2,090.3	991.1	1,205.4
NET INCOME	$ 1,601.2	$ 753.3	$ 915.8
U.S. \| TOTAL ASSETS \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	72.00%	74.00%	77.00%
U.S. \| TOTAL REVENUE \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	73.00%	68.00%	66.00%
U.S. \| INCOME BEFORE INCOME TAXES \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	79.00%	68.00%	68.00%
U.S. \| NET INCOME \| Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	79.00%	68.00%	69.00%

Amount of asset recognized for present right to economic benefit.

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